Jo Shields 3c1f479b9d Imported Upstream version 4.0.0~alpha1
Former-commit-id: 806294f5ded97629b74c85c09952f2a74fe182d9
2015-04-07 09:35:12 +01:00

2626 lines
75 KiB
C

/*
* mini-gc.c: GC interface for the mono JIT
*
* Author:
* Zoltan Varga (vargaz@gmail.com)
*
* Copyright 2009 Novell, Inc (http://www.novell.com)
* Copyright 2011 Xamarin, Inc (http://www.xamarin.com)
*/
#include "config.h"
#include "mini-gc.h"
#include <mono/metadata/gc-internal.h>
#if 0
//#if defined(MONO_ARCH_GC_MAPS_SUPPORTED)
#include <mono/metadata/sgen-conf.h>
#include <mono/metadata/gc-internal.h>
#include <mono/utils/mono-counters.h>
#define SIZEOF_SLOT ((int)sizeof (mgreg_t))
#define GC_BITS_PER_WORD (sizeof (mword) * 8)
/* Contains state needed by the GC Map construction code */
typedef struct {
/*
* This contains information about stack slots initialized in the prolog, encoded using
* (slot_index << 16) | slot_type. The slot_index is relative to the CFA, i.e. 0
* means cfa+0, 1 means cfa-4/8, etc.
*/
GSList *stack_slots_from_cfa;
/* Same for stack slots relative to the frame pointer */
GSList *stack_slots_from_fp;
/* Number of slots in the map */
int nslots;
/* The number of registers in the map */
int nregs;
/* Min and Max offsets of the stack frame relative to fp */
int min_offset, max_offset;
/* Same for the locals area */
int locals_min_offset, locals_max_offset;
/* The call sites where this frame can be stopped during GC */
GCCallSite **callsites;
/* The number of call sites */
int ncallsites;
/*
* The width of the stack bitmaps in bytes. This is not equal to the bitmap width at
* runtime, since it includes columns which are 0.
*/
int stack_bitmap_width;
/*
* A bitmap whose width equals nslots, and whose height equals ncallsites.
* The bitmap contains a 1 if the corresponding stack slot has type SLOT_REF at the
* given callsite.
*/
guint8 *stack_ref_bitmap;
/* Same for SLOT_PIN */
guint8 *stack_pin_bitmap;
/*
* Similar bitmaps for registers. These have width MONO_MAX_IREGS in bits.
*/
int reg_bitmap_width;
guint8 *reg_ref_bitmap;
guint8 *reg_pin_bitmap;
} MonoCompileGC;
#define ALIGN_TO(val,align) ((((mgreg_t)val) + ((align) - 1)) & ~((align) - 1))
#undef DEBUG
#if 0
/* We don't support debug levels, its all-or-nothing */
#define DEBUG(s) do { s; fflush (logfile); } while (0)
#define DEBUG_ENABLED 1
#else
#define DEBUG(s)
#endif
#ifdef DEBUG_ENABLED
//#if 1
#define DEBUG_PRECISE(s) do { s; } while (0)
#define DEBUG_PRECISE_ENABLED
#else
#define DEBUG_PRECISE(s)
#endif
/*
* Contains information collected during the conservative stack marking pass,
* used during the precise pass. This helps to avoid doing a stack walk twice, which
* is expensive.
*/
typedef struct {
guint8 *bitmap;
int nslots;
int frame_start_offset;
int nreg_locations;
/* Relative to stack_start */
int reg_locations [MONO_MAX_IREGS];
#ifdef DEBUG_PRECISE_ENABLED
MonoJitInfo *ji;
gpointer fp;
int regs [MONO_MAX_IREGS];
#endif
} FrameInfo;
/* Max number of frames stored in the TLS data */
#define MAX_FRAMES 50
/*
* Per-thread data kept by this module. This is stored in the GC and passed to us as
* parameters, instead of being stored in a TLS variable, since during a collection,
* only the collection thread is active.
*/
typedef struct {
MonoThreadUnwindState unwind_state;
MonoThreadInfo *info;
/* For debugging */
mgreg_t tid;
gpointer ref_to_track;
/* Number of frames collected during the !precise pass */
int nframes;
FrameInfo frames [MAX_FRAMES];
} TlsData;
/* These are constant so don't store them in the GC Maps */
/* Number of registers stored in gc maps */
#define NREGS MONO_MAX_IREGS
/*
* The GC Map itself.
* Contains information needed to mark a stack frame.
* This is a transient structure, created from a compressed representation on-demand.
*/
typedef struct {
/*
* The offsets of the GC tracked area inside the stack frame relative to the frame pointer.
* This includes memory which is NOREF thus doesn't need GC maps.
*/
int start_offset;
int end_offset;
/*
* The offset relative to frame_offset where the the memory described by the GC maps
* begins.
*/
int map_offset;
/* The number of stack slots in the map */
int nslots;
/* The frame pointer register */
guint8 frame_reg;
/* The size of each callsite table entry */
guint8 callsite_entry_size;
guint has_pin_slots : 1;
guint has_ref_slots : 1;
guint has_ref_regs : 1;
guint has_pin_regs : 1;
/* The offsets below are into an external bitmaps array */
/*
* A bitmap whose width is equal to bitmap_width, and whose height is equal to ncallsites.
* The bitmap contains a 1 if the corresponding stack slot has type SLOT_REF at the
* given callsite.
*/
guint32 stack_ref_bitmap_offset;
/*
* Same for SLOT_PIN. It is possible that the same bit is set in both bitmaps at
* different callsites, if the slot starts out as PIN, and later changes to REF.
*/
guint32 stack_pin_bitmap_offset;
/*
* Corresponding bitmaps for registers
* These have width equal to the number of bits set in reg_ref_mask/reg_pin_mask.
* FIXME: Merge these with the normal bitmaps, i.e. reserve the first x slots for them ?
*/
guint32 reg_pin_bitmap_offset;
guint32 reg_ref_bitmap_offset;
guint32 used_int_regs, reg_ref_mask, reg_pin_mask;
/* The number of bits set in the two masks above */
guint8 nref_regs, npin_regs;
/*
* A bit array marking slots which contain refs.
* This is used only for debugging.
*/
//guint8 *ref_slots;
/* Callsite offsets */
/* These can take up a lot of space, so encode them compactly */
union {
guint8 *offsets8;
guint16 *offsets16;
guint32 *offsets32;
} callsites;
int ncallsites;
} GCMap;
/*
* A compressed version of GCMap. This is what gets stored in MonoJitInfo.
*/
typedef struct {
//guint8 *ref_slots;
//guint8 encoded_size;
/*
* The arrays below are embedded after the struct.
* Their address needs to be computed.
*/
/* The fixed fields of the GCMap encoded using LEB128 */
guint8 encoded [MONO_ZERO_LEN_ARRAY];
/* An array of ncallsites entries, each entry is callsite_entry_size bytes long */
guint8 callsites [MONO_ZERO_LEN_ARRAY];
/* The GC bitmaps */
guint8 bitmaps [MONO_ZERO_LEN_ARRAY];
} GCEncodedMap;
static int precise_frame_count [2], precise_frame_limit = -1;
static gboolean precise_frame_limit_inited;
/* Stats */
typedef struct {
int scanned_stacks;
int scanned;
int scanned_precisely;
int scanned_conservatively;
int scanned_registers;
int scanned_native;
int scanned_other;
int all_slots;
int noref_slots;
int ref_slots;
int pin_slots;
int gc_maps_size;
int gc_callsites_size;
int gc_callsites8_size;
int gc_callsites16_size;
int gc_callsites32_size;
int gc_bitmaps_size;
int gc_map_struct_size;
int tlsdata_size;
} JITGCStats;
static JITGCStats stats;
static FILE *logfile;
static gboolean enable_gc_maps_for_aot;
void
mini_gc_enable_gc_maps_for_aot (void)
{
enable_gc_maps_for_aot = TRUE;
}
// FIXME: Move these to a shared place
static inline void
encode_uleb128 (guint32 value, guint8 *buf, guint8 **endbuf)
{
guint8 *p = buf;
do {
guint8 b = value & 0x7f;
value >>= 7;
if (value != 0) /* more bytes to come */
b |= 0x80;
*p ++ = b;
} while (value);
*endbuf = p;
}
static G_GNUC_UNUSED void
encode_sleb128 (gint32 value, guint8 *buf, guint8 **endbuf)
{
gboolean more = 1;
gboolean negative = (value < 0);
guint32 size = 32;
guint8 byte;
guint8 *p = buf;
while (more) {
byte = value & 0x7f;
value >>= 7;
/* the following is unnecessary if the
* implementation of >>= uses an arithmetic rather
* than logical shift for a signed left operand
*/
if (negative)
/* sign extend */
value |= - (1 <<(size - 7));
/* sign bit of byte is second high order bit (0x40) */
if ((value == 0 && !(byte & 0x40)) ||
(value == -1 && (byte & 0x40)))
more = 0;
else
byte |= 0x80;
*p ++= byte;
}
*endbuf = p;
}
static inline guint32
decode_uleb128 (guint8 *buf, guint8 **endbuf)
{
guint8 *p = buf;
guint32 res = 0;
int shift = 0;
while (TRUE) {
guint8 b = *p;
p ++;
res = res | (((int)(b & 0x7f)) << shift);
if (!(b & 0x80))
break;
shift += 7;
}
*endbuf = p;
return res;
}
static inline gint32
decode_sleb128 (guint8 *buf, guint8 **endbuf)
{
guint8 *p = buf;
gint32 res = 0;
int shift = 0;
while (TRUE) {
guint8 b = *p;
p ++;
res = res | (((int)(b & 0x7f)) << shift);
shift += 7;
if (!(b & 0x80)) {
if (shift < 32 && (b & 0x40))
res |= - (1 << shift);
break;
}
}
*endbuf = p;
return res;
}
static int
encode_frame_reg (int frame_reg)
{
#ifdef TARGET_AMD64
if (frame_reg == AMD64_RSP)
return 0;
else if (frame_reg == AMD64_RBP)
return 1;
#elif defined(TARGET_X86)
if (frame_reg == X86_EBP)
return 0;
else if (frame_reg == X86_ESP)
return 1;
#elif defined(TARGET_ARM)
if (frame_reg == ARMREG_SP)
return 0;
else if (frame_reg == ARMREG_FP)
return 1;
#elif defined(TARGET_S390X)
if (frame_reg == S390_SP)
return 0;
else if (frame_reg == S390_FP)
return 1;
#else
NOT_IMPLEMENTED;
#endif
g_assert_not_reached ();
return -1;
}
static int
decode_frame_reg (int encoded)
{
#ifdef TARGET_AMD64
if (encoded == 0)
return AMD64_RSP;
else if (encoded == 1)
return AMD64_RBP;
#elif defined(TARGET_X86)
if (encoded == 0)
return X86_EBP;
else if (encoded == 1)
return X86_ESP;
#elif defined(TARGET_ARM)
if (encoded == 0)
return ARMREG_SP;
else if (encoded == 1)
return ARMREG_FP;
#elif defined(TARGET_S390X)
if (encoded == 0)
return S390_SP;
else if (encoded == 1)
return S390_FP;
#else
NOT_IMPLEMENTED;
#endif
g_assert_not_reached ();
return -1;
}
#ifdef TARGET_AMD64
#ifdef HOST_WIN32
static int callee_saved_regs [] = { AMD64_RBP, AMD64_RBX, AMD64_R12, AMD64_R13, AMD64_R14, AMD64_R15, AMD64_RDI, AMD64_RSI };
#else
static int callee_saved_regs [] = { AMD64_RBP, AMD64_RBX, AMD64_R12, AMD64_R13, AMD64_R14, AMD64_R15 };
#endif
#elif defined(TARGET_X86)
static int callee_saved_regs [] = { X86_EBX, X86_ESI, X86_EDI };
#elif defined(TARGET_ARM)
static int callee_saved_regs [] = { ARMREG_V1, ARMREG_V2, ARMREG_V3, ARMREG_V4, ARMREG_V5, ARMREG_V7, ARMREG_FP };
#elif defined(TARGET_ARM64)
// FIXME:
static int callee_saved_regs [] = { };
#elif defined(TARGET_S390X)
static int callee_saved_regs [] = { s390_r6, s390_r7, s390_r8, s390_r9, s390_r10, s390_r11, s390_r12, s390_r13, s390_r14 };
#elif defined(TARGET_POWERPC64) && _CALL_ELF == 2
static int callee_saved_regs [] = {
ppc_r13, ppc_r14, ppc_r15, ppc_r16,
ppc_r17, ppc_r18, ppc_r19, ppc_r20,
ppc_r21, ppc_r22, ppc_r23, ppc_r24,
ppc_r25, ppc_r26, ppc_r27, ppc_r28,
ppc_r29, ppc_r30, ppc_r31 };
#elif defined(TARGET_POWERPC)
static int callee_saved_regs [] = { ppc_r6, ppc_r7, ppc_r8, ppc_r9, ppc_r10, ppc_r11, ppc_r12, ppc_r13, ppc_r14 };
#endif
static guint32
encode_regmask (guint32 regmask)
{
int i;
guint32 res;
res = 0;
for (i = 0; i < sizeof (callee_saved_regs) / sizeof (int); ++i) {
if (regmask & (1 << callee_saved_regs [i])) {
res |= (1 << i);
regmask -= (1 << callee_saved_regs [i]);
}
}
g_assert (regmask == 0);
return res;
}
static guint32
decode_regmask (guint32 regmask)
{
int i;
guint32 res;
res = 0;
for (i = 0; i < sizeof (callee_saved_regs) / sizeof (int); ++i)
if (regmask & (1 << i))
res |= (1 << callee_saved_regs [i]);
return res;
}
/*
* encode_gc_map:
*
* Encode the fixed fields of MAP into a buffer pointed to by BUF.
*/
static void
encode_gc_map (GCMap *map, guint8 *buf, guint8 **endbuf)
{
guint32 flags, freg;
encode_sleb128 (map->start_offset / SIZEOF_SLOT, buf, &buf);
encode_sleb128 (map->end_offset / SIZEOF_SLOT, buf, &buf);
encode_sleb128 (map->map_offset / SIZEOF_SLOT, buf, &buf);
encode_uleb128 (map->nslots, buf, &buf);
g_assert (map->callsite_entry_size <= 4);
freg = encode_frame_reg (map->frame_reg);
g_assert (freg < 2);
flags = (map->has_ref_slots ? 1 : 0) | (map->has_pin_slots ? 2 : 0) | (map->has_ref_regs ? 4 : 0) | (map->has_pin_regs ? 8 : 0) | ((map->callsite_entry_size - 1) << 4) | (freg << 6);
encode_uleb128 (flags, buf, &buf);
encode_uleb128 (encode_regmask (map->used_int_regs), buf, &buf);
if (map->has_ref_regs)
encode_uleb128 (encode_regmask (map->reg_ref_mask), buf, &buf);
if (map->has_pin_regs)
encode_uleb128 (encode_regmask (map->reg_pin_mask), buf, &buf);
encode_uleb128 (map->ncallsites, buf, &buf);
*endbuf = buf;
}
/*
* decode_gc_map:
*
* Decode the encoded GC map representation in BUF and store the result into MAP.
*/
static void
decode_gc_map (guint8 *buf, GCMap *map, guint8 **endbuf)
{
guint32 flags;
int stack_bitmap_size, reg_ref_bitmap_size, reg_pin_bitmap_size, offset, freg;
int i, n;
map->start_offset = decode_sleb128 (buf, &buf) * SIZEOF_SLOT;
map->end_offset = decode_sleb128 (buf, &buf) * SIZEOF_SLOT;
map->map_offset = decode_sleb128 (buf, &buf) * SIZEOF_SLOT;
map->nslots = decode_uleb128 (buf, &buf);
flags = decode_uleb128 (buf, &buf);
map->has_ref_slots = (flags & 1) ? 1 : 0;
map->has_pin_slots = (flags & 2) ? 1 : 0;
map->has_ref_regs = (flags & 4) ? 1 : 0;
map->has_pin_regs = (flags & 8) ? 1 : 0;
map->callsite_entry_size = ((flags >> 4) & 0x3) + 1;
freg = flags >> 6;
map->frame_reg = decode_frame_reg (freg);
map->used_int_regs = decode_regmask (decode_uleb128 (buf, &buf));
if (map->has_ref_regs) {
map->reg_ref_mask = decode_regmask (decode_uleb128 (buf, &buf));
n = 0;
for (i = 0; i < NREGS; ++i)
if (map->reg_ref_mask & (1 << i))
n ++;
map->nref_regs = n;
}
if (map->has_pin_regs) {
map->reg_pin_mask = decode_regmask (decode_uleb128 (buf, &buf));
n = 0;
for (i = 0; i < NREGS; ++i)
if (map->reg_pin_mask & (1 << i))
n ++;
map->npin_regs = n;
}
map->ncallsites = decode_uleb128 (buf, &buf);
stack_bitmap_size = (ALIGN_TO (map->nslots, 8) / 8) * map->ncallsites;
reg_ref_bitmap_size = (ALIGN_TO (map->nref_regs, 8) / 8) * map->ncallsites;
reg_pin_bitmap_size = (ALIGN_TO (map->npin_regs, 8) / 8) * map->ncallsites;
offset = 0;
map->stack_ref_bitmap_offset = offset;
if (map->has_ref_slots)
offset += stack_bitmap_size;
map->stack_pin_bitmap_offset = offset;
if (map->has_pin_slots)
offset += stack_bitmap_size;
map->reg_ref_bitmap_offset = offset;
if (map->has_ref_regs)
offset += reg_ref_bitmap_size;
map->reg_pin_bitmap_offset = offset;
if (map->has_pin_regs)
offset += reg_pin_bitmap_size;
*endbuf = buf;
}
static gpointer
thread_attach_func (void)
{
TlsData *tls;
tls = g_new0 (TlsData, 1);
tls->tid = GetCurrentThreadId ();
tls->info = mono_thread_info_current ();
stats.tlsdata_size += sizeof (TlsData);
return tls;
}
static void
thread_detach_func (gpointer user_data)
{
TlsData *tls = user_data;
g_free (tls);
}
static void
thread_suspend_func (gpointer user_data, void *sigctx, MonoContext *ctx)
{
TlsData *tls = user_data;
if (!tls) {
/* Happens during startup */
return;
}
if (tls->tid != GetCurrentThreadId ()) {
/* Happens on osx because threads are not suspended using signals */
#ifndef TARGET_WIN32
gboolean res;
#endif
g_assert (tls->info);
#ifdef TARGET_WIN32
return;
#else
res = mono_thread_state_init_from_handle (&tls->unwind_state, tls->info);
#endif
} else {
tls->unwind_state.unwind_data [MONO_UNWIND_DATA_LMF] = mono_get_lmf ();
if (sigctx) {
#ifdef MONO_ARCH_HAVE_SIGCTX_TO_MONOCTX
mono_sigctx_to_monoctx (sigctx, &tls->unwind_state.ctx);
tls->unwind_state.valid = TRUE;
#else
tls->unwind_state.valid = FALSE;
#endif
} else if (ctx) {
memcpy (&tls->unwind_state.ctx, ctx, sizeof (MonoContext));
tls->unwind_state.valid = TRUE;
} else {
tls->unwind_state.valid = FALSE;
}
tls->unwind_state.unwind_data [MONO_UNWIND_DATA_JIT_TLS] = mono_native_tls_get_value (mono_jit_tls_id);
tls->unwind_state.unwind_data [MONO_UNWIND_DATA_DOMAIN] = mono_domain_get ();
}
if (!tls->unwind_state.unwind_data [MONO_UNWIND_DATA_DOMAIN]) {
/* Happens during startup */
tls->unwind_state.valid = FALSE;
return;
}
}
#define DEAD_REF ((gpointer)(gssize)0x2a2a2a2a2a2a2a2aULL)
static inline void
set_bit (guint8 *bitmap, int width, int y, int x)
{
bitmap [(width * y) + (x / 8)] |= (1 << (x % 8));
}
static inline void
clear_bit (guint8 *bitmap, int width, int y, int x)
{
bitmap [(width * y) + (x / 8)] &= ~(1 << (x % 8));
}
static inline int
get_bit (guint8 *bitmap, int width, int y, int x)
{
return bitmap [(width * y) + (x / 8)] & (1 << (x % 8));
}
static const char*
slot_type_to_string (GCSlotType type)
{
switch (type) {
case SLOT_REF:
return "ref";
case SLOT_NOREF:
return "noref";
case SLOT_PIN:
return "pin";
default:
g_assert_not_reached ();
return NULL;
}
}
static inline mgreg_t
get_frame_pointer (MonoContext *ctx, int frame_reg)
{
#if defined(TARGET_AMD64)
if (frame_reg == AMD64_RSP)
return ctx->rsp;
else if (frame_reg == AMD64_RBP)
return ctx->rbp;
#elif defined(TARGET_X86)
if (frame_reg == X86_ESP)
return ctx->esp;
else if (frame_reg == X86_EBP)
return ctx->ebp;
#elif defined(TARGET_ARM)
if (frame_reg == ARMREG_SP)
return (mgreg_t)MONO_CONTEXT_GET_SP (ctx);
else if (frame_reg == ARMREG_FP)
return (mgreg_t)MONO_CONTEXT_GET_BP (ctx);
#elif defined(TARGET_S390X)
if (frame_reg == S390_SP)
return (mgreg_t)MONO_CONTEXT_GET_SP (ctx);
else if (frame_reg == S390_FP)
return (mgreg_t)MONO_CONTEXT_GET_BP (ctx);
#endif
g_assert_not_reached ();
return 0;
}
/*
* conservatively_pass:
*
* Mark a thread stack conservatively and collect information needed by the precise pass.
*/
static void
conservative_pass (TlsData *tls, guint8 *stack_start, guint8 *stack_end)
{
MonoJitInfo *ji;
MonoMethod *method;
MonoContext ctx, new_ctx;
MonoLMF *lmf;
guint8 *stack_limit;
gboolean last = TRUE;
GCMap *map;
GCMap map_tmp;
GCEncodedMap *emap;
guint8* fp, *p, *real_frame_start, *frame_start, *frame_end;
int i, pc_offset, cindex, bitmap_width;
int scanned = 0, scanned_precisely, scanned_conservatively, scanned_registers;
gboolean res;
StackFrameInfo frame;
mgreg_t *reg_locations [MONO_MAX_IREGS];
mgreg_t *new_reg_locations [MONO_MAX_IREGS];
guint8 *bitmaps;
FrameInfo *fi;
guint32 precise_regmask;
if (tls) {
tls->nframes = 0;
tls->ref_to_track = NULL;
}
/* tls == NULL can happen during startup */
if (mono_thread_internal_current () == NULL || !tls) {
mono_gc_conservatively_scan_area (stack_start, stack_end);
stats.scanned_stacks += stack_end - stack_start;
return;
}
lmf = tls->unwind_state.unwind_data [MONO_UNWIND_DATA_LMF];
frame.domain = NULL;
/* Number of bytes scanned based on GC map data */
scanned = 0;
/* Number of bytes scanned precisely based on GC map data */
scanned_precisely = 0;
/* Number of bytes scanned conservatively based on GC map data */
scanned_conservatively = 0;
/* Number of bytes scanned conservatively in register save areas */
scanned_registers = 0;
/* This is one past the last address which we have scanned */
stack_limit = stack_start;
if (!tls->unwind_state.valid)
memset (&new_ctx, 0, sizeof (ctx));
else
memcpy (&new_ctx, &tls->unwind_state.ctx, sizeof (MonoContext));
memset (reg_locations, 0, sizeof (reg_locations));
memset (new_reg_locations, 0, sizeof (new_reg_locations));
while (TRUE) {
if (!tls->unwind_state.valid)
break;
memcpy (&ctx, &new_ctx, sizeof (ctx));
for (i = 0; i < MONO_MAX_IREGS; ++i) {
if (new_reg_locations [i]) {
/*
* If the current frame saves the register, it means it might modify its
* value, thus the old location might not contain the same value, so
* we have to mark it conservatively.
*/
if (reg_locations [i]) {
DEBUG (fprintf (logfile, "\tscan saved reg %s location %p.\n", mono_arch_regname (i), reg_locations [i]));
mono_gc_conservatively_scan_area (reg_locations [i], (char*)reg_locations [i] + SIZEOF_SLOT);
scanned_registers += SIZEOF_SLOT;
}
reg_locations [i] = new_reg_locations [i];
DEBUG (fprintf (logfile, "\treg %s is now at location %p.\n", mono_arch_regname (i), reg_locations [i]));
}
}
g_assert ((mgreg_t)stack_limit % SIZEOF_SLOT == 0);
res = mono_find_jit_info_ext (frame.domain ? frame.domain : tls->unwind_state.unwind_data [MONO_UNWIND_DATA_DOMAIN], tls->unwind_state.unwind_data [MONO_UNWIND_DATA_JIT_TLS], NULL, &ctx, &new_ctx, NULL, &lmf, new_reg_locations, &frame);
if (!res)
break;
ji = frame.ji;
// FIXME: For skipped frames, scan the param area of the parent frame conservatively ?
if (frame.type == FRAME_TYPE_MANAGED_TO_NATIVE) {
/*
* These frames are problematic for several reasons:
* - they are unwound through an LMF, and we have no precise register tracking for those.
* - the LMF might not contain a precise ip, so we can't compute the call site.
* - the LMF only unwinds to the wrapper frame, so we get these methods twice.
*/
DEBUG (fprintf (logfile, "Mark(0): <Managed-to-native transition>\n"));
for (i = 0; i < MONO_MAX_IREGS; ++i) {
if (reg_locations [i]) {
DEBUG (fprintf (logfile, "\tscan saved reg %s location %p.\n", mono_arch_regname (i), reg_locations [i]));
mono_gc_conservatively_scan_area (reg_locations [i], (char*)reg_locations [i] + SIZEOF_SLOT);
scanned_registers += SIZEOF_SLOT;
}
reg_locations [i] = NULL;
new_reg_locations [i] = NULL;
}
ctx = new_ctx;
continue;
}
if (ji)
method = jinfo_get_method (ji);
else
method = NULL;
/* The last frame can be in any state so mark conservatively */
if (last) {
if (ji) {
DEBUG (char *fname = mono_method_full_name (method, TRUE); fprintf (logfile, "Mark(0): %s+0x%x (%p)\n", fname, pc_offset, (gpointer)MONO_CONTEXT_GET_IP (&ctx)); g_free (fname));
}
DEBUG (fprintf (logfile, "\t <Last frame>\n"));
last = FALSE;
/*
* new_reg_locations is not precise when a method is interrupted during its epilog, so clear it.
*/
for (i = 0; i < MONO_MAX_IREGS; ++i) {
if (reg_locations [i]) {
DEBUG (fprintf (logfile, "\tscan saved reg %s location %p.\n", mono_arch_regname (i), reg_locations [i]));
mono_gc_conservatively_scan_area (reg_locations [i], (char*)reg_locations [i] + SIZEOF_SLOT);
scanned_registers += SIZEOF_SLOT;
}
if (new_reg_locations [i]) {
DEBUG (fprintf (logfile, "\tscan saved reg %s location %p.\n", mono_arch_regname (i), new_reg_locations [i]));
mono_gc_conservatively_scan_area (new_reg_locations [i], (char*)new_reg_locations [i] + SIZEOF_SLOT);
scanned_registers += SIZEOF_SLOT;
}
reg_locations [i] = NULL;
new_reg_locations [i] = NULL;
}
continue;
}
pc_offset = (guint8*)MONO_CONTEXT_GET_IP (&ctx) - (guint8*)ji->code_start;
/* These frames are very problematic */
if (method->wrapper_type == MONO_WRAPPER_MANAGED_TO_NATIVE) {
DEBUG (char *fname = mono_method_full_name (method, TRUE); fprintf (logfile, "Mark(0): %s+0x%x (%p)\n", fname, pc_offset, (gpointer)MONO_CONTEXT_GET_IP (&ctx)); g_free (fname));
DEBUG (fprintf (logfile, "\tSkip.\n"));
continue;
}
/* All the other frames are at a call site */
if (tls->nframes == MAX_FRAMES) {
/*
* Can't save information since the array is full. So scan the rest of the
* stack conservatively.
*/
DEBUG (fprintf (logfile, "Mark (0): Frame stack full.\n"));
break;
}
/* Scan the frame of this method */
/*
* A frame contains the following:
* - saved registers
* - saved args
* - locals
* - spill area
* - localloc-ed memory
*/
g_assert (pc_offset >= 0);
emap = ji->gc_info;
if (!emap) {
DEBUG (char *fname = mono_method_full_name (jinfo_get_method (ji), TRUE); fprintf (logfile, "Mark(0): %s+0x%x (%p)\n", fname, pc_offset, (gpointer)MONO_CONTEXT_GET_IP (&ctx)); g_free (fname));
DEBUG (fprintf (logfile, "\tNo GC Map.\n"));
continue;
}
/* The embedded callsite table requires this */
g_assert (((mgreg_t)emap % 4) == 0);
/*
* Debugging aid to control the number of frames scanned precisely
*/
if (!precise_frame_limit_inited) {
if (g_getenv ("MONO_PRECISE_COUNT"))
precise_frame_limit = atoi (g_getenv ("MONO_PRECISE_COUNT"));
precise_frame_limit_inited = TRUE;
}
if (precise_frame_limit != -1) {
if (precise_frame_count [FALSE] == precise_frame_limit)
printf ("LAST PRECISE FRAME: %s\n", mono_method_full_name (method, TRUE));
if (precise_frame_count [FALSE] > precise_frame_limit)
continue;
}
precise_frame_count [FALSE] ++;
/* Decode the encoded GC map */
map = &map_tmp;
memset (map, 0, sizeof (GCMap));
decode_gc_map (&emap->encoded [0], map, &p);
p = (guint8*)ALIGN_TO (p, map->callsite_entry_size);
map->callsites.offsets8 = p;
p += map->callsite_entry_size * map->ncallsites;
bitmaps = p;
fp = (guint8*)get_frame_pointer (&ctx, map->frame_reg);
real_frame_start = fp + map->start_offset;
frame_start = fp + map->start_offset + map->map_offset;
frame_end = fp + map->end_offset;
DEBUG (char *fname = mono_method_full_name (jinfo_get_method (ji), TRUE); fprintf (logfile, "Mark(0): %s+0x%x (%p) limit=%p fp=%p frame=%p-%p (%d)\n", fname, pc_offset, (gpointer)MONO_CONTEXT_GET_IP (&ctx), stack_limit, fp, frame_start, frame_end, (int)(frame_end - frame_start)); g_free (fname));
/* Find the callsite index */
if (map->callsite_entry_size == 1) {
for (i = 0; i < map->ncallsites; ++i)
/* ip points inside the call instruction */
if (map->callsites.offsets8 [i] == pc_offset + 1)
break;
} else if (map->callsite_entry_size == 2) {
// FIXME: Use a binary search
for (i = 0; i < map->ncallsites; ++i)
/* ip points inside the call instruction */
if (map->callsites.offsets16 [i] == pc_offset + 1)
break;
} else {
// FIXME: Use a binary search
for (i = 0; i < map->ncallsites; ++i)
/* ip points inside the call instruction */
if (map->callsites.offsets32 [i] == pc_offset + 1)
break;
}
if (i == map->ncallsites) {
printf ("Unable to find ip offset 0x%x in callsite list of %s.\n", pc_offset + 1, mono_method_full_name (method, TRUE));
g_assert_not_reached ();
}
cindex = i;
/*
* This is not neccessary true on x86 because frames have a different size at each
* call site.
*/
//g_assert (real_frame_start >= stack_limit);
if (real_frame_start > stack_limit) {
/* This scans the previously skipped frames as well */
DEBUG (fprintf (logfile, "\tscan area %p-%p (%d).\n", stack_limit, real_frame_start, (int)(real_frame_start - stack_limit)));
mono_gc_conservatively_scan_area (stack_limit, real_frame_start);
stats.scanned_other += real_frame_start - stack_limit;
}
/* Mark stack slots */
if (map->has_pin_slots) {
int bitmap_width = ALIGN_TO (map->nslots, 8) / 8;
guint8 *pin_bitmap = &bitmaps [map->stack_pin_bitmap_offset + (bitmap_width * cindex)];
guint8 *p;
gboolean pinned;
p = frame_start;
for (i = 0; i < map->nslots; ++i) {
pinned = pin_bitmap [i / 8] & (1 << (i % 8));
if (pinned) {
DEBUG (fprintf (logfile, "\tscan slot %s0x%x(fp)=%p.\n", (guint8*)p > (guint8*)fp ? "" : "-", ABS ((int)((gssize)p - (gssize)fp)), p));
mono_gc_conservatively_scan_area (p, p + SIZEOF_SLOT);
scanned_conservatively += SIZEOF_SLOT;
} else {
scanned_precisely += SIZEOF_SLOT;
}
p += SIZEOF_SLOT;
}
} else {
scanned_precisely += (map->nslots * SIZEOF_SLOT);
}
/* The area outside of start-end is NOREF */
scanned_precisely += (map->end_offset - map->start_offset) - (map->nslots * SIZEOF_SLOT);
/* Mark registers */
precise_regmask = map->used_int_regs | (1 << map->frame_reg);
if (map->has_pin_regs) {
int bitmap_width = ALIGN_TO (map->npin_regs, 8) / 8;
guint8 *pin_bitmap = &bitmaps [map->reg_pin_bitmap_offset + (bitmap_width * cindex)];
int bindex = 0;
for (i = 0; i < NREGS; ++i) {
if (!(map->used_int_regs & (1 << i)))
continue;
if (!(map->reg_pin_mask & (1 << i)))
continue;
if (pin_bitmap [bindex / 8] & (1 << (bindex % 8))) {
DEBUG (fprintf (logfile, "\treg %s saved at 0x%p is pinning.\n", mono_arch_regname (i), reg_locations [i]));
precise_regmask &= ~(1 << i);
}
bindex ++;
}
}
scanned += map->end_offset - map->start_offset;
g_assert (scanned == scanned_precisely + scanned_conservatively);
stack_limit = frame_end;
/* Save information for the precise pass */
fi = &tls->frames [tls->nframes];
fi->nslots = map->nslots;
bitmap_width = ALIGN_TO (map->nslots, 8) / 8;
if (map->has_ref_slots)
fi->bitmap = &bitmaps [map->stack_ref_bitmap_offset + (bitmap_width * cindex)];
else
fi->bitmap = NULL;
fi->frame_start_offset = frame_start - stack_start;
fi->nreg_locations = 0;
DEBUG_PRECISE (fi->ji = ji);
DEBUG_PRECISE (fi->fp = fp);
if (map->has_ref_regs) {
int bitmap_width = ALIGN_TO (map->nref_regs, 8) / 8;
guint8 *ref_bitmap = &bitmaps [map->reg_ref_bitmap_offset + (bitmap_width * cindex)];
int bindex = 0;
for (i = 0; i < NREGS; ++i) {
if (!(map->reg_ref_mask & (1 << i)))
continue;
if (reg_locations [i] && (ref_bitmap [bindex / 8] & (1 << (bindex % 8)))) {
DEBUG_PRECISE (fi->regs [fi->nreg_locations] = i);
DEBUG (fprintf (logfile, "\treg %s saved at 0x%p is ref.\n", mono_arch_regname (i), reg_locations [i]));
fi->reg_locations [fi->nreg_locations] = (guint8*)reg_locations [i] - stack_start;
fi->nreg_locations ++;
}
bindex ++;
}
}
/*
* Clear locations of precisely tracked registers.
*/
if (precise_regmask) {
for (i = 0; i < NREGS; ++i) {
if (precise_regmask & (1 << i)) {
/*
* The method uses this register, and we have precise info for it.
* This means the location will be scanned precisely.
* Tell the code at the beginning of the loop that this location is
* processed.
*/
if (reg_locations [i])
DEBUG (fprintf (logfile, "\treg %s at location %p (==%p) is precise.\n", mono_arch_regname (i), reg_locations [i], (gpointer)*reg_locations [i]));
reg_locations [i] = NULL;
}
}
}
tls->nframes ++;
}
/* Scan the remaining register save locations */
for (i = 0; i < MONO_MAX_IREGS; ++i) {
if (reg_locations [i]) {
DEBUG (fprintf (logfile, "\tscan saved reg location %p.\n", reg_locations [i]));
mono_gc_conservatively_scan_area (reg_locations [i], (char*)reg_locations [i] + SIZEOF_SLOT);
scanned_registers += SIZEOF_SLOT;
}
if (new_reg_locations [i]) {
DEBUG (fprintf (logfile, "\tscan saved reg location %p.\n", new_reg_locations [i]));
mono_gc_conservatively_scan_area (new_reg_locations [i], (char*)new_reg_locations [i] + SIZEOF_SLOT);
scanned_registers += SIZEOF_SLOT;
}
}
if (stack_limit < stack_end) {
DEBUG (fprintf (logfile, "\tscan remaining stack %p-%p (%d).\n", stack_limit, stack_end, (int)(stack_end - stack_limit)));
mono_gc_conservatively_scan_area (stack_limit, stack_end);
stats.scanned_native += stack_end - stack_limit;
}
DEBUG (fprintf (logfile, "Marked %d bytes, p=%d,c=%d out of %d.\n", scanned, scanned_precisely, scanned_conservatively, (int)(stack_end - stack_start)));
stats.scanned_stacks += stack_end - stack_start;
stats.scanned += scanned;
stats.scanned_precisely += scanned_precisely;
stats.scanned_conservatively += scanned_conservatively;
stats.scanned_registers += scanned_registers;
//mono_gc_conservatively_scan_area (stack_start, stack_end);
}
/*
* precise_pass:
*
* Mark a thread stack precisely based on information saved during the conservative
* pass.
*/
static void
precise_pass (TlsData *tls, guint8 *stack_start, guint8 *stack_end, void *gc_data)
{
int findex, i;
FrameInfo *fi;
guint8 *frame_start;
if (!tls)
return;
if (!tls->unwind_state.valid)
return;
for (findex = 0; findex < tls->nframes; findex ++) {
/* Load information saved by the !precise pass */
fi = &tls->frames [findex];
frame_start = stack_start + fi->frame_start_offset;
DEBUG (char *fname = mono_method_full_name (jinfo_get_method (fi->ji), TRUE); fprintf (logfile, "Mark(1): %s\n", fname); g_free (fname));
/*
* FIXME: Add a function to mark using a bitmap, to avoid doing a
* call for each object.
*/
/* Mark stack slots */
if (fi->bitmap) {
guint8 *ref_bitmap = fi->bitmap;
gboolean live;
for (i = 0; i < fi->nslots; ++i) {
MonoObject **ptr = (MonoObject**)(frame_start + (i * SIZEOF_SLOT));
live = ref_bitmap [i / 8] & (1 << (i % 8));
if (live) {
MonoObject *obj = *ptr;
if (obj) {
DEBUG (fprintf (logfile, "\tref %s0x%x(fp)=%p: %p ->", (guint8*)ptr >= (guint8*)fi->fp ? "" : "-", ABS ((int)((gssize)ptr - (gssize)fi->fp)), ptr, obj));
*ptr = mono_gc_scan_object (obj, gc_data);
DEBUG (fprintf (logfile, " %p.\n", *ptr));
} else {
DEBUG (fprintf (logfile, "\tref %s0x%x(fp)=%p: %p.\n", (guint8*)ptr >= (guint8*)fi->fp ? "" : "-", ABS ((int)((gssize)ptr - (gssize)fi->fp)), ptr, obj));
}
} else {
#if 0
/*
* This is disabled because the pointer takes up a lot of space.
* Stack slots might be shared between ref and non-ref variables ?
*/
if (map->ref_slots [i / 8] & (1 << (i % 8))) {
DEBUG (fprintf (logfile, "\tref %s0x%x(fp)=%p: dead (%p)\n", (guint8*)ptr >= (guint8*)fi->fp ? "" : "-", ABS ((int)((gssize)ptr - (gssize)fi->fp)), ptr, *ptr));
/*
* Fail fast if the live range is incorrect, and
* the JITted code tries to access this object
*/
*ptr = DEAD_REF;
}
#endif
}
}
}
/* Mark registers */
/*
* Registers are different from stack slots, they have no address where they
* are stored. Instead, some frame below this frame in the stack saves them
* in its prolog to the stack. We can mark this location precisely.
*/
for (i = 0; i < fi->nreg_locations; ++i) {
/*
* reg_locations [i] contains the address of the stack slot where
* a reg was last saved, so mark that slot.
*/
MonoObject **ptr = (MonoObject**)((guint8*)stack_start + fi->reg_locations [i]);
MonoObject *obj = *ptr;
if (obj) {
DEBUG (fprintf (logfile, "\treg %s saved at %p: %p ->", mono_arch_regname (fi->regs [i]), ptr, obj));
*ptr = mono_gc_scan_object (obj, gc_data);
DEBUG (fprintf (logfile, " %p.\n", *ptr));
} else {
DEBUG (fprintf (logfile, "\treg %s saved at %p: %p\n", mono_arch_regname (fi->regs [i]), ptr, obj));
}
}
}
/*
* Debugging aid to check for missed refs.
*/
if (tls->ref_to_track) {
mgreg_t *p;
for (p = (mgreg_t*)stack_start; p < (mgreg_t*)stack_end; ++p)
if (*p == (mgreg_t)tls->ref_to_track)
printf ("REF AT %p.\n", p);
}
}
/*
* thread_mark_func:
*
* This is called by the GC twice to mark a thread stack. PRECISE is FALSE at the first
* call, and TRUE at the second. USER_DATA points to a TlsData
* structure filled up by thread_suspend_func.
*/
static void
thread_mark_func (gpointer user_data, guint8 *stack_start, guint8 *stack_end, gboolean precise, void *gc_data)
{
TlsData *tls = user_data;
DEBUG (fprintf (logfile, "****************************************\n"));
DEBUG (fprintf (logfile, "*** %s stack marking for thread %p (%p-%p) ***\n", precise ? "Precise" : "Conservative", tls ? GUINT_TO_POINTER (tls->tid) : NULL, stack_start, stack_end));
DEBUG (fprintf (logfile, "****************************************\n"));
if (!precise)
conservative_pass (tls, stack_start, stack_end);
else
precise_pass (tls, stack_start, stack_end, gc_data);
}
#ifndef DISABLE_JIT
static void
mini_gc_init_gc_map (MonoCompile *cfg)
{
if (COMPILE_LLVM (cfg))
return;
if (!mono_gc_is_moving ())
return;
if (cfg->compile_aot) {
if (!enable_gc_maps_for_aot)
return;
} else if (!mono_gc_precise_stack_mark_enabled ())
return;
#if 1
/* Debugging support */
{
static int precise_count;
precise_count ++;
if (g_getenv ("MONO_GCMAP_COUNT")) {
if (precise_count == atoi (g_getenv ("MONO_GCMAP_COUNT")))
printf ("LAST: %s\n", mono_method_full_name (cfg->method, TRUE));
if (precise_count > atoi (g_getenv ("MONO_GCMAP_COUNT")))
return;
}
}
#endif
cfg->compute_gc_maps = TRUE;
cfg->gc_info = mono_mempool_alloc0 (cfg->mempool, sizeof (MonoCompileGC));
}
/*
* mini_gc_set_slot_type_from_fp:
*
* Set the GC slot type of the stack slot identified by SLOT_OFFSET, which should be
* relative to the frame pointer. By default, all stack slots are type PIN, so there is no
* need to call this function for those slots.
*/
void
mini_gc_set_slot_type_from_fp (MonoCompile *cfg, int slot_offset, GCSlotType type)
{
MonoCompileGC *gcfg = (MonoCompileGC*)cfg->gc_info;
if (!cfg->compute_gc_maps)
return;
g_assert (slot_offset % SIZEOF_SLOT == 0);
gcfg->stack_slots_from_fp = g_slist_prepend_mempool (cfg->mempool, gcfg->stack_slots_from_fp, GINT_TO_POINTER (((slot_offset) << 16) | type));
}
/*
* mini_gc_set_slot_type_from_cfa:
*
* Set the GC slot type of the stack slot identified by SLOT_OFFSET, which should be
* relative to the DWARF CFA value. This should be called from mono_arch_emit_prolog ().
* If type is STACK_REF, the slot is assumed to be live from the end of the prolog until
* the end of the method. By default, all stack slots are type PIN, so there is no need to
* call this function for those slots.
*/
void
mini_gc_set_slot_type_from_cfa (MonoCompile *cfg, int slot_offset, GCSlotType type)
{
MonoCompileGC *gcfg = (MonoCompileGC*)cfg->gc_info;
int slot = - (slot_offset / SIZEOF_SLOT);
if (!cfg->compute_gc_maps)
return;
g_assert (slot_offset <= 0);
g_assert (slot_offset % SIZEOF_SLOT == 0);
gcfg->stack_slots_from_cfa = g_slist_prepend_mempool (cfg->mempool, gcfg->stack_slots_from_cfa, GUINT_TO_POINTER (((slot) << 16) | type));
}
static inline int
fp_offset_to_slot (MonoCompile *cfg, int offset)
{
MonoCompileGC *gcfg = cfg->gc_info;
return (offset - gcfg->min_offset) / SIZEOF_SLOT;
}
static inline int
slot_to_fp_offset (MonoCompile *cfg, int slot)
{
MonoCompileGC *gcfg = cfg->gc_info;
return (slot * SIZEOF_SLOT) + gcfg->min_offset;
}
static inline MONO_ALWAYS_INLINE void
set_slot (MonoCompileGC *gcfg, int slot, int callsite_index, GCSlotType type)
{
g_assert (slot >= 0 && slot < gcfg->nslots);
if (type == SLOT_PIN) {
clear_bit (gcfg->stack_ref_bitmap, gcfg->stack_bitmap_width, slot, callsite_index);
set_bit (gcfg->stack_pin_bitmap, gcfg->stack_bitmap_width, slot, callsite_index);
} else if (type == SLOT_REF) {
set_bit (gcfg->stack_ref_bitmap, gcfg->stack_bitmap_width, slot, callsite_index);
clear_bit (gcfg->stack_pin_bitmap, gcfg->stack_bitmap_width, slot, callsite_index);
} else if (type == SLOT_NOREF) {
clear_bit (gcfg->stack_ref_bitmap, gcfg->stack_bitmap_width, slot, callsite_index);
clear_bit (gcfg->stack_pin_bitmap, gcfg->stack_bitmap_width, slot, callsite_index);
}
}
static inline void
set_slot_everywhere (MonoCompileGC *gcfg, int slot, GCSlotType type)
{
int width, pos;
guint8 *ref_bitmap, *pin_bitmap;
/*
int cindex;
for (cindex = 0; cindex < gcfg->ncallsites; ++cindex)
set_slot (gcfg, slot, cindex, type);
*/
ref_bitmap = gcfg->stack_ref_bitmap;
pin_bitmap = gcfg->stack_pin_bitmap;
width = gcfg->stack_bitmap_width;
pos = width * slot;
if (type == SLOT_PIN) {
memset (ref_bitmap + pos, 0, width);
memset (pin_bitmap + pos, 0xff, width);
} else if (type == SLOT_REF) {
memset (ref_bitmap + pos, 0xff, width);
memset (pin_bitmap + pos, 0, width);
} else if (type == SLOT_NOREF) {
memset (ref_bitmap + pos, 0, width);
memset (pin_bitmap + pos, 0, width);
}
}
static inline void
set_slot_in_range (MonoCompileGC *gcfg, int slot, int from, int to, GCSlotType type)
{
int cindex;
for (cindex = 0; cindex < gcfg->ncallsites; ++cindex) {
int callsite_offset = gcfg->callsites [cindex]->pc_offset;
if (callsite_offset >= from && callsite_offset < to)
set_slot (gcfg, slot, cindex, type);
}
}
static inline void
set_reg_slot (MonoCompileGC *gcfg, int slot, int callsite_index, GCSlotType type)
{
g_assert (slot >= 0 && slot < gcfg->nregs);
if (type == SLOT_PIN) {
clear_bit (gcfg->reg_ref_bitmap, gcfg->reg_bitmap_width, slot, callsite_index);
set_bit (gcfg->reg_pin_bitmap, gcfg->reg_bitmap_width, slot, callsite_index);
} else if (type == SLOT_REF) {
set_bit (gcfg->reg_ref_bitmap, gcfg->reg_bitmap_width, slot, callsite_index);
clear_bit (gcfg->reg_pin_bitmap, gcfg->reg_bitmap_width, slot, callsite_index);
} else if (type == SLOT_NOREF) {
clear_bit (gcfg->reg_ref_bitmap, gcfg->reg_bitmap_width, slot, callsite_index);
clear_bit (gcfg->reg_pin_bitmap, gcfg->reg_bitmap_width, slot, callsite_index);
}
}
static inline void
set_reg_slot_everywhere (MonoCompileGC *gcfg, int slot, GCSlotType type)
{
int cindex;
for (cindex = 0; cindex < gcfg->ncallsites; ++cindex)
set_reg_slot (gcfg, slot, cindex, type);
}
static inline void
set_reg_slot_in_range (MonoCompileGC *gcfg, int slot, int from, int to, GCSlotType type)
{
int cindex;
for (cindex = 0; cindex < gcfg->ncallsites; ++cindex) {
int callsite_offset = gcfg->callsites [cindex]->pc_offset;
if (callsite_offset >= from && callsite_offset < to)
set_reg_slot (gcfg, slot, cindex, type);
}
}
static void
process_spill_slots (MonoCompile *cfg)
{
MonoCompileGC *gcfg = cfg->gc_info;
MonoBasicBlock *bb;
GSList *l;
int i;
/* Mark all ref/pin spill slots as NOREF by default outside of their live range */
for (bb = cfg->bb_entry; bb; bb = bb->next_bb) {
for (l = bb->spill_slot_defs; l; l = l->next) {
MonoInst *def = l->data;
int spill_slot = def->inst_c0;
int bank = def->inst_c1;
int offset = cfg->spill_info [bank][spill_slot].offset;
int slot = fp_offset_to_slot (cfg, offset);
if (bank == MONO_REG_INT_MP || bank == MONO_REG_INT_REF)
set_slot_everywhere (gcfg, slot, SLOT_NOREF);
}
}
for (bb = cfg->bb_entry; bb; bb = bb->next_bb) {
for (l = bb->spill_slot_defs; l; l = l->next) {
MonoInst *def = l->data;
int spill_slot = def->inst_c0;
int bank = def->inst_c1;
int offset = cfg->spill_info [bank][spill_slot].offset;
int slot = fp_offset_to_slot (cfg, offset);
GCSlotType type;
if (bank == MONO_REG_INT_MP)
type = SLOT_PIN;
else
type = SLOT_REF;
/*
* Extend the live interval for the GC tracked spill slots
* defined in this bblock.
* FIXME: This is not needed.
*/
set_slot_in_range (gcfg, slot, def->backend.pc_offset, bb->native_offset + bb->native_length, type);
if (cfg->verbose_level > 1)
printf ("\t%s spill slot at %s0x%x(fp) (slot = %d)\n", slot_type_to_string (type), offset >= 0 ? "" : "-", ABS (offset), slot);
}
}
/* Set fp spill slots to NOREF */
for (i = 0; i < cfg->spill_info_len [MONO_REG_DOUBLE]; ++i) {
int offset = cfg->spill_info [MONO_REG_DOUBLE][i].offset;
int slot;
if (offset == -1)
continue;
slot = fp_offset_to_slot (cfg, offset);
set_slot_everywhere (gcfg, slot, SLOT_NOREF);
/* FIXME: 32 bit */
if (cfg->verbose_level > 1)
printf ("\tfp spill slot at %s0x%x(fp) (slot = %d)\n", offset >= 0 ? "" : "-", ABS (offset), slot);
}
/* Set int spill slots to NOREF */
for (i = 0; i < cfg->spill_info_len [MONO_REG_INT]; ++i) {
int offset = cfg->spill_info [MONO_REG_INT][i].offset;
int slot;
if (offset == -1)
continue;
slot = fp_offset_to_slot (cfg, offset);
set_slot_everywhere (gcfg, slot, SLOT_NOREF);
if (cfg->verbose_level > 1)
printf ("\tint spill slot at %s0x%x(fp) (slot = %d)\n", offset >= 0 ? "" : "-", ABS (offset), slot);
}
}
/*
* process_other_slots:
*
* Process stack slots registered using mini_gc_set_slot_type_... ().
*/
static void
process_other_slots (MonoCompile *cfg)
{
MonoCompileGC *gcfg = cfg->gc_info;
GSList *l;
/* Relative to the CFA */
for (l = gcfg->stack_slots_from_cfa; l; l = l->next) {
guint data = GPOINTER_TO_UINT (l->data);
int cfa_slot = data >> 16;
GCSlotType type = data & 0xff;
int slot;
/*
* Map the cfa relative slot to an fp relative slot.
* slot_addr == cfa - <cfa_slot>*4/8
* fp + cfa_offset == cfa
* -> slot_addr == fp + (cfa_offset - <cfa_slot>*4/8)
*/
slot = (cfg->cfa_offset / SIZEOF_SLOT) - cfa_slot - (gcfg->min_offset / SIZEOF_SLOT);
set_slot_everywhere (gcfg, slot, type);
if (cfg->verbose_level > 1) {
int fp_offset = slot_to_fp_offset (cfg, slot);
if (type == SLOT_NOREF)
printf ("\tnoref slot at %s0x%x(fp) (slot = %d) (cfa - 0x%x)\n", fp_offset >= 0 ? "" : "-", ABS (fp_offset), slot, (int)(cfa_slot * SIZEOF_SLOT));
}
}
/* Relative to the FP */
for (l = gcfg->stack_slots_from_fp; l; l = l->next) {
gint data = GPOINTER_TO_INT (l->data);
int offset = data >> 16;
GCSlotType type = data & 0xff;
int slot;
slot = fp_offset_to_slot (cfg, offset);
set_slot_everywhere (gcfg, slot, type);
/* Liveness for these slots is handled by process_spill_slots () */
if (cfg->verbose_level > 1) {
if (type == SLOT_REF)
printf ("\tref slot at fp+0x%x (slot = %d)\n", offset, slot);
else if (type == SLOT_NOREF)
printf ("\tnoref slot at 0x%x(fp) (slot = %d)\n", offset, slot);
}
}
}
static gsize*
get_vtype_bitmap (MonoType *t, int *numbits)
{
MonoClass *klass = mono_class_from_mono_type (t);
if (klass->generic_container || mono_class_is_open_constructed_type (t)) {
/* FIXME: Generic sharing */
return NULL;
} else {
mono_class_compute_gc_descriptor (klass);
return mono_gc_get_bitmap_for_descr (klass->gc_descr, numbits);
}
}
static inline const char*
get_offset_sign (int offset)
{
return offset < 0 ? "-" : "+";
}
static inline int
get_offset_val (int offset)
{
return offset < 0 ? (- offset) : offset;
}
static void
process_variables (MonoCompile *cfg)
{
MonoCompileGC *gcfg = cfg->gc_info;
MonoMethodSignature *sig = mono_method_signature (cfg->method);
int i, locals_min_slot, locals_max_slot, cindex;
MonoBasicBlock *bb;
MonoInst *tmp;
int *pc_offsets;
int locals_min_offset = gcfg->locals_min_offset;
int locals_max_offset = gcfg->locals_max_offset;
/* Slots for locals are NOREF by default */
locals_min_slot = (locals_min_offset - gcfg->min_offset) / SIZEOF_SLOT;
locals_max_slot = (locals_max_offset - gcfg->min_offset) / SIZEOF_SLOT;
for (i = locals_min_slot; i < locals_max_slot; ++i) {
set_slot_everywhere (gcfg, i, SLOT_NOREF);
}
/*
* Compute the offset where variables are initialized in the first bblock, if any.
*/
pc_offsets = g_new0 (int, cfg->next_vreg);
bb = cfg->bb_entry->next_bb;
MONO_BB_FOR_EACH_INS (bb, tmp) {
if (tmp->opcode == OP_GC_LIVENESS_DEF) {
int vreg = tmp->inst_c1;
if (pc_offsets [vreg] == 0) {
g_assert (tmp->backend.pc_offset > 0);
pc_offsets [vreg] = tmp->backend.pc_offset;
}
}
}
/*
* Stack slots holding arguments are initialized in the prolog.
* This means we can treat them alive for the whole method.
*/
for (i = 0; i < cfg->num_varinfo; i++) {
MonoInst *ins = cfg->varinfo [i];
MonoType *t = ins->inst_vtype;
MonoMethodVar *vmv;
guint32 pos;
gboolean byref, is_this = FALSE;
gboolean is_arg = i < cfg->locals_start;
if (ins == cfg->ret) {
if (!(ins->opcode == OP_REGOFFSET && MONO_TYPE_ISSTRUCT (t)))
continue;
}
vmv = MONO_VARINFO (cfg, i);
/* For some reason, 'this' is byref */
if (sig->hasthis && ins == cfg->args [0] && !cfg->method->klass->valuetype) {
t = &cfg->method->klass->byval_arg;
is_this = TRUE;
}
byref = t->byref;
if (ins->opcode == OP_REGVAR) {
int hreg;
GCSlotType slot_type;
t = mini_type_get_underlying_type (NULL, t);
hreg = ins->dreg;
g_assert (hreg < MONO_MAX_IREGS);
if (byref)
slot_type = SLOT_PIN;
else
slot_type = mini_type_is_reference (cfg, t) ? SLOT_REF : SLOT_NOREF;
if (slot_type == SLOT_PIN) {
/* These have no live interval, be conservative */
set_reg_slot_everywhere (gcfg, hreg, slot_type);
} else {
/*
* Unlike variables allocated to the stack, we generate liveness info
* for noref vars in registers in mono_spill_global_vars (), because
* knowing that a register doesn't contain a ref allows us to mark its save
* locations precisely.
*/
for (cindex = 0; cindex < gcfg->ncallsites; ++cindex)
if (gcfg->callsites [cindex]->liveness [i / 8] & (1 << (i % 8)))
set_reg_slot (gcfg, hreg, cindex, slot_type);
}
if (cfg->verbose_level > 1) {
printf ("\t%s %sreg %s(R%d)\n", slot_type_to_string (slot_type), is_arg ? "arg " : "", mono_arch_regname (hreg), vmv->vreg);
}
continue;
}
if (ins->opcode != OP_REGOFFSET)
continue;
if (ins->inst_offset % SIZEOF_SLOT != 0)
continue;
pos = fp_offset_to_slot (cfg, ins->inst_offset);
if (is_arg && ins->flags & MONO_INST_IS_DEAD) {
/* These do not get stored in the prolog */
set_slot_everywhere (gcfg, pos, SLOT_NOREF);
if (cfg->verbose_level > 1) {
printf ("\tdead arg at fp%s0x%x (slot = %d): %s\n", get_offset_sign (ins->inst_offset), get_offset_val (ins->inst_offset), pos, mono_type_full_name (ins->inst_vtype));
}
continue;
}
if (MONO_TYPE_ISSTRUCT (t)) {
int numbits = 0, j;
gsize *bitmap = NULL;
gboolean pin = FALSE;
int size;
int size_in_slots;
if (ins->backend.is_pinvoke)
size = mono_class_native_size (ins->klass, NULL);
else
size = mono_class_value_size (ins->klass, NULL);
size_in_slots = ALIGN_TO (size, SIZEOF_SLOT) / SIZEOF_SLOT;
if (cfg->verbose_level > 1)
printf ("\tvtype R%d at %s0x%x(fp)-%s0x%x(fp) (slot %d-%d): %s\n", vmv->vreg, get_offset_sign (ins->inst_offset), get_offset_val (ins->inst_offset), get_offset_sign (ins->inst_offset), get_offset_val (ins->inst_offset + (size_in_slots * SIZEOF_SLOT)), pos, pos + size_in_slots, mono_type_full_name (ins->inst_vtype));
if (!ins->klass->has_references) {
if (is_arg) {
for (j = 0; j < size_in_slots; ++j)
set_slot_everywhere (gcfg, pos + j, SLOT_NOREF);
}
continue;
}
bitmap = get_vtype_bitmap (t, &numbits);
if (!bitmap)
pin = TRUE;
/*
* Most vtypes are marked volatile because of the LDADDR instructions,
* and they have no liveness information since they are decomposed
* before the liveness pass. We emit OP_GC_LIVENESS_DEF instructions for
* them during VZERO decomposition.
*/
if (!is_arg) {
if (!pc_offsets [vmv->vreg])
pin = TRUE;
if (ins->backend.is_pinvoke)
pin = TRUE;
}
if (bitmap) {
for (cindex = 0; cindex < gcfg->ncallsites; ++cindex) {
if (gcfg->callsites [cindex]->pc_offset > pc_offsets [vmv->vreg]) {
for (j = 0; j < numbits; ++j) {
if (bitmap [j / GC_BITS_PER_WORD] & ((gsize)1 << (j % GC_BITS_PER_WORD))) {
/* The descriptor is for the boxed object */
set_slot (gcfg, (pos + j - (sizeof (MonoObject) / SIZEOF_SLOT)), cindex, pin ? SLOT_PIN : SLOT_REF);
}
}
}
}
if (cfg->verbose_level > 1) {
for (j = 0; j < numbits; ++j) {
if (bitmap [j / GC_BITS_PER_WORD] & ((gsize)1 << (j % GC_BITS_PER_WORD)))
printf ("\t\t%s slot at 0x%x(fp) (slot = %d)\n", pin ? "pin" : "ref", (int)(ins->inst_offset + (j * SIZEOF_SLOT)), (int)(pos + j - (sizeof (MonoObject) / SIZEOF_SLOT)));
}
}
} else {
if (cfg->verbose_level > 1)
printf ("\t\tpinned\n");
for (j = 0; j < size_in_slots; ++j) {
set_slot_everywhere (gcfg, pos + j, SLOT_PIN);
}
}
g_free (bitmap);
continue;
}
if (!is_arg && (ins->inst_offset < gcfg->min_offset || ins->inst_offset >= gcfg->max_offset))
/* Vret addr etc. */
continue;
if (t->byref) {
if (is_arg) {
set_slot_everywhere (gcfg, pos, SLOT_PIN);
} else {
for (cindex = 0; cindex < gcfg->ncallsites; ++cindex)
if (gcfg->callsites [cindex]->liveness [i / 8] & (1 << (i % 8)))
set_slot (gcfg, pos, cindex, SLOT_PIN);
}
if (cfg->verbose_level > 1)
printf ("\tbyref at %s0x%x(fp) (R%d, slot = %d): %s\n", ins->inst_offset < 0 ? "-" : "", (ins->inst_offset < 0) ? -(int)ins->inst_offset : (int)ins->inst_offset, vmv->vreg, pos, mono_type_full_name (ins->inst_vtype));
continue;
}
/*
* This is currently disabled, but could be enabled to debug crashes.
*/
#if 0
if (t->type == MONO_TYPE_I) {
/*
* Variables created in mono_handle_global_vregs have type I, but they
* could hold GC refs since the vregs they were created from might not been
* marked as holding a GC ref. So be conservative.
*/
set_slot_everywhere (gcfg, pos, SLOT_PIN);
continue;
}
#endif
t = mini_type_get_underlying_type (NULL, t);
if (!mini_type_is_reference (cfg, t)) {
set_slot_everywhere (gcfg, pos, SLOT_NOREF);
if (cfg->verbose_level > 1)
printf ("\tnoref%s at %s0x%x(fp) (R%d, slot = %d): %s\n", (is_arg ? " arg" : ""), ins->inst_offset < 0 ? "-" : "", (ins->inst_offset < 0) ? -(int)ins->inst_offset : (int)ins->inst_offset, vmv->vreg, pos, mono_type_full_name (ins->inst_vtype));
if (!t->byref && sizeof (mgreg_t) == 4 && (t->type == MONO_TYPE_I8 || t->type == MONO_TYPE_U8 || t->type == MONO_TYPE_R8)) {
set_slot_everywhere (gcfg, pos + 1, SLOT_NOREF);
if (cfg->verbose_level > 1)
printf ("\tnoref at %s0x%x(fp) (R%d, slot = %d): %s\n", ins->inst_offset < 0 ? "-" : "", (ins->inst_offset < 0) ? -(int)(ins->inst_offset + 4) : (int)ins->inst_offset + 4, vmv->vreg, pos + 1, mono_type_full_name (ins->inst_vtype));
}
continue;
}
/* 'this' is marked INDIRECT for gshared methods */
if (ins->flags & (MONO_INST_VOLATILE | MONO_INST_INDIRECT) && !is_this) {
/*
* For volatile variables, treat them alive from the point they are
* initialized in the first bblock until the end of the method.
*/
if (is_arg) {
set_slot_everywhere (gcfg, pos, SLOT_REF);
} else if (pc_offsets [vmv->vreg]) {
set_slot_in_range (gcfg, pos, 0, pc_offsets [vmv->vreg], SLOT_PIN);
set_slot_in_range (gcfg, pos, pc_offsets [vmv->vreg], cfg->code_size, SLOT_REF);
} else {
set_slot_everywhere (gcfg, pos, SLOT_PIN);
}
if (cfg->verbose_level > 1)
printf ("\tvolatile ref at %s0x%x(fp) (R%d, slot = %d): %s\n", ins->inst_offset < 0 ? "-" : "", (ins->inst_offset < 0) ? -(int)ins->inst_offset : (int)ins->inst_offset, vmv->vreg, pos, mono_type_full_name (ins->inst_vtype));
continue;
}
if (is_arg) {
/* Live for the whole method */
set_slot_everywhere (gcfg, pos, SLOT_REF);
} else {
for (cindex = 0; cindex < gcfg->ncallsites; ++cindex)
if (gcfg->callsites [cindex]->liveness [i / 8] & (1 << (i % 8)))
set_slot (gcfg, pos, cindex, SLOT_REF);
}
if (cfg->verbose_level > 1) {
printf ("\tref%s at %s0x%x(fp) (R%d, slot = %d): %s\n", (is_arg ? " arg" : ""), ins->inst_offset < 0 ? "-" : "", (ins->inst_offset < 0) ? -(int)ins->inst_offset : (int)ins->inst_offset, vmv->vreg, pos, mono_type_full_name (ins->inst_vtype));
}
}
g_free (pc_offsets);
}
static int
sp_offset_to_fp_offset (MonoCompile *cfg, int sp_offset)
{
/*
* Convert a sp relative offset to a slot index. This is
* platform specific.
*/
#ifdef TARGET_AMD64
/* fp = sp + offset */
g_assert (cfg->frame_reg == AMD64_RBP);
return (- cfg->arch.sp_fp_offset + sp_offset);
#elif defined(TARGET_X86)
/* The offset is computed from the sp at the start of the call sequence */
g_assert (cfg->frame_reg == X86_EBP);
#ifdef MONO_X86_NO_PUSHES
return (- cfg->arch.sp_fp_offset + sp_offset);
#else
return (- cfg->arch.sp_fp_offset - sp_offset);
#endif
#else
NOT_IMPLEMENTED;
return -1;
#endif
}
static void
process_param_area_slots (MonoCompile *cfg)
{
MonoCompileGC *gcfg = cfg->gc_info;
int cindex, i;
gboolean *is_param;
/*
* These slots are used for passing parameters during calls. They are sp relative, not
* fp relative, so they are harder to handle.
*/
if (cfg->flags & MONO_CFG_HAS_ALLOCA)
/* The distance between fp and sp is not constant */
return;
is_param = mono_mempool_alloc0 (cfg->mempool, gcfg->nslots * sizeof (gboolean));
for (cindex = 0; cindex < gcfg->ncallsites; ++cindex) {
GCCallSite *callsite = gcfg->callsites [cindex];
GSList *l;
for (l = callsite->param_slots; l; l = l->next) {
MonoInst *def = l->data;
MonoType *t = def->inst_vtype;
int sp_offset = def->inst_offset;
int fp_offset = sp_offset_to_fp_offset (cfg, sp_offset);
int slot = fp_offset_to_slot (cfg, fp_offset);
guint32 align;
guint32 size;
if (MONO_TYPE_ISSTRUCT (t)) {
size = mini_type_stack_size_full (cfg->generic_sharing_context, t, &align, FALSE);
} else {
size = sizeof (mgreg_t);
}
for (i = 0; i < size / sizeof (mgreg_t); ++i) {
g_assert (slot + i >= 0 && slot + i < gcfg->nslots);
is_param [slot + i] = TRUE;
}
}
}
/* All param area slots are noref by default */
for (i = 0; i < gcfg->nslots; ++i) {
if (is_param [i])
set_slot_everywhere (gcfg, i, SLOT_NOREF);
}
/*
* We treat param area slots as being part of the callee's frame, to be able to handle tail calls which overwrite
* the argument area of the caller.
*/
}
static void
process_finally_clauses (MonoCompile *cfg)
{
MonoCompileGC *gcfg = cfg->gc_info;
GCCallSite **callsites;
int ncallsites;
gboolean has_finally;
int i, j, nslots, nregs;
ncallsites = gcfg->ncallsites;
nslots = gcfg->nslots;
nregs = gcfg->nregs;
callsites = gcfg->callsites;
/*
* The calls to the finally clauses don't show up in the cfg. See
* test_0_liveness_8 ().
* Variables accessed inside the finally clause are already marked VOLATILE by
* mono_liveness_handle_exception_clauses (). Variables not accessed inside the finally clause have
* correct liveness outside the finally clause. So mark them PIN inside the finally clauses.
*/
has_finally = FALSE;
for (i = 0; i < cfg->header->num_clauses; ++i) {
MonoExceptionClause *clause = &cfg->header->clauses [i];
if (clause->flags == MONO_EXCEPTION_CLAUSE_FINALLY) {
has_finally = TRUE;
}
}
if (has_finally) {
if (cfg->verbose_level > 1)
printf ("\tMethod has finally clauses, pessimizing live ranges.\n");
for (j = 0; j < ncallsites; ++j) {
MonoBasicBlock *bb = callsites [j]->bb;
MonoExceptionClause *clause;
gboolean is_in_finally = FALSE;
for (i = 0; i < cfg->header->num_clauses; ++i) {
clause = &cfg->header->clauses [i];
if (MONO_OFFSET_IN_HANDLER (clause, bb->real_offset)) {
if (clause->flags == MONO_EXCEPTION_CLAUSE_FINALLY) {
is_in_finally = TRUE;
break;
}
}
}
if (is_in_finally) {
for (i = 0; i < nslots; ++i)
set_slot (gcfg, i, j, SLOT_PIN);
for (i = 0; i < nregs; ++i)
set_reg_slot (gcfg, i, j, SLOT_PIN);
}
}
}
}
static void
compute_frame_size (MonoCompile *cfg)
{
int i, locals_min_offset, locals_max_offset, cfa_min_offset, cfa_max_offset;
int min_offset, max_offset;
MonoCompileGC *gcfg = cfg->gc_info;
MonoMethodSignature *sig = mono_method_signature (cfg->method);
GSList *l;
/* Compute min/max offsets from the fp */
/* Locals */
#if defined(TARGET_AMD64) || defined(TARGET_X86) || defined(TARGET_ARM) || defined(TARGET_S390X)
locals_min_offset = ALIGN_TO (cfg->locals_min_stack_offset, SIZEOF_SLOT);
locals_max_offset = cfg->locals_max_stack_offset;
#else
/* min/max stack offset needs to be computed in mono_arch_allocate_vars () */
NOT_IMPLEMENTED;
#endif
locals_min_offset = ALIGN_TO (locals_min_offset, SIZEOF_SLOT);
locals_max_offset = ALIGN_TO (locals_max_offset, SIZEOF_SLOT);
min_offset = locals_min_offset;
max_offset = locals_max_offset;
/* Arguments */
for (i = 0; i < sig->param_count + sig->hasthis; ++i) {
MonoInst *ins = cfg->args [i];
if (ins->opcode == OP_REGOFFSET) {
int size, size_in_slots;
size = mini_type_stack_size_full (cfg->generic_sharing_context, ins->inst_vtype, NULL, ins->backend.is_pinvoke);
size_in_slots = ALIGN_TO (size, SIZEOF_SLOT) / SIZEOF_SLOT;
min_offset = MIN (min_offset, ins->inst_offset);
max_offset = MAX ((int)max_offset, (int)(ins->inst_offset + (size_in_slots * SIZEOF_SLOT)));
}
}
/* Cfa slots */
g_assert (cfg->frame_reg == cfg->cfa_reg);
g_assert (cfg->cfa_offset > 0);
cfa_min_offset = 0;
cfa_max_offset = cfg->cfa_offset;
min_offset = MIN (min_offset, cfa_min_offset);
max_offset = MAX (max_offset, cfa_max_offset);
/* Fp relative slots */
for (l = gcfg->stack_slots_from_fp; l; l = l->next) {
gint data = GPOINTER_TO_INT (l->data);
int offset = data >> 16;
min_offset = MIN (min_offset, offset);
}
/* Spill slots */
if (!(cfg->flags & MONO_CFG_HAS_SPILLUP)) {
int stack_offset = ALIGN_TO (cfg->stack_offset, SIZEOF_SLOT);
min_offset = MIN (min_offset, (-stack_offset));
}
/* Param area slots */
#ifdef TARGET_AMD64
min_offset = MIN (min_offset, -cfg->arch.sp_fp_offset);
#elif defined(TARGET_X86)
#ifdef MONO_X86_NO_PUSHES
min_offset = MIN (min_offset, -cfg->arch.sp_fp_offset);
#else
min_offset = MIN (min_offset, - (cfg->arch.sp_fp_offset + cfg->arch.param_area_size));
#endif
#elif defined(TARGET_ARM)
// FIXME:
#elif defined(TARGET_s390X)
// FIXME:
#else
NOT_IMPLEMENTED;
#endif
gcfg->min_offset = min_offset;
gcfg->max_offset = max_offset;
gcfg->locals_min_offset = locals_min_offset;
gcfg->locals_max_offset = locals_max_offset;
}
static void
init_gcfg (MonoCompile *cfg)
{
int i, nregs, nslots;
MonoCompileGC *gcfg = cfg->gc_info;
GCCallSite **callsites;
int ncallsites;
MonoBasicBlock *bb;
GSList *l;
/*
* Collect callsites
*/
ncallsites = 0;
for (bb = cfg->bb_entry; bb; bb = bb->next_bb) {
ncallsites += g_slist_length (bb->gc_callsites);
}
callsites = mono_mempool_alloc0 (cfg->mempool, ncallsites * sizeof (GCCallSite*));
i = 0;
for (bb = cfg->bb_entry; bb; bb = bb->next_bb) {
for (l = bb->gc_callsites; l; l = l->next)
callsites [i++] = l->data;
}
/* The callsites should already be ordered by pc offset */
for (i = 1; i < ncallsites; ++i)
g_assert (callsites [i - 1]->pc_offset < callsites [i]->pc_offset);
/*
* The stack frame looks like this:
*
* <fp + max_offset> == cfa -> <end of previous frame>
* <other stack slots>
* <locals>
* <other stack slots>
* fp + min_offset ->
* ...
* fp ->
*/
if (cfg->verbose_level > 1)
printf ("GC Map for %s: 0x%x-0x%x\n", mono_method_full_name (cfg->method, TRUE), gcfg->min_offset, gcfg->max_offset);
nslots = (gcfg->max_offset - gcfg->min_offset) / SIZEOF_SLOT;
nregs = NREGS;
gcfg->nslots = nslots;
gcfg->nregs = nregs;
gcfg->callsites = callsites;
gcfg->ncallsites = ncallsites;
gcfg->stack_bitmap_width = ALIGN_TO (ncallsites, 8) / 8;
gcfg->reg_bitmap_width = ALIGN_TO (ncallsites, 8) / 8;
gcfg->stack_ref_bitmap = mono_mempool_alloc0 (cfg->mempool, gcfg->stack_bitmap_width * nslots);
gcfg->stack_pin_bitmap = mono_mempool_alloc0 (cfg->mempool, gcfg->stack_bitmap_width * nslots);
gcfg->reg_ref_bitmap = mono_mempool_alloc0 (cfg->mempool, gcfg->reg_bitmap_width * nregs);
gcfg->reg_pin_bitmap = mono_mempool_alloc0 (cfg->mempool, gcfg->reg_bitmap_width * nregs);
/* All slots start out as PIN */
memset (gcfg->stack_pin_bitmap, 0xff, gcfg->stack_bitmap_width * nregs);
for (i = 0; i < nregs; ++i) {
/*
* By default, registers are NOREF.
* It is possible for a callee to save them before being defined in this method,
* but the saved value is dead too, so it doesn't need to be marked.
*/
if ((cfg->used_int_regs & (1 << i)))
set_reg_slot_everywhere (gcfg, i, SLOT_NOREF);
}
}
static inline gboolean
has_bit_set (guint8 *bitmap, int width, int slot)
{
int i;
int pos = width * slot;
for (i = 0; i < width; ++i) {
if (bitmap [pos + i])
break;
}
return i < width;
}
static void
create_map (MonoCompile *cfg)
{
GCMap *map;
int i, j, nregs, nslots, nref_regs, npin_regs, alloc_size, bitmaps_size, bitmaps_offset;
int ntypes [16];
int stack_bitmap_width, stack_bitmap_size, reg_ref_bitmap_width, reg_ref_bitmap_size;
int reg_pin_bitmap_width, reg_pin_bitmap_size, bindex;
int start, end;
gboolean has_ref_slots, has_pin_slots, has_ref_regs, has_pin_regs;
MonoCompileGC *gcfg = cfg->gc_info;
GCCallSite **callsites;
int ncallsites;
guint8 *bitmap, *bitmaps;
guint32 reg_ref_mask, reg_pin_mask;
ncallsites = gcfg->ncallsites;
nslots = gcfg->nslots;
nregs = gcfg->nregs;
callsites = gcfg->callsites;
/*
* Compute the real size of the bitmap i.e. ignore NOREF columns at the beginning and at
* the end. Also, compute whenever the map needs ref/pin bitmaps, and collect stats.
*/
has_ref_slots = FALSE;
has_pin_slots = FALSE;
start = -1;
end = -1;
memset (ntypes, 0, sizeof (ntypes));
for (i = 0; i < nslots; ++i) {
gboolean has_ref = FALSE;
gboolean has_pin = FALSE;
if (has_bit_set (gcfg->stack_pin_bitmap, gcfg->stack_bitmap_width, i))
has_pin = TRUE;
if (has_bit_set (gcfg->stack_ref_bitmap, gcfg->stack_bitmap_width, i))
has_ref = TRUE;
if (has_ref)
has_ref_slots = TRUE;
if (has_pin)
has_pin_slots = TRUE;
if (has_ref)
ntypes [SLOT_REF] ++;
else if (has_pin)
ntypes [SLOT_PIN] ++;
else
ntypes [SLOT_NOREF] ++;
if (has_ref || has_pin) {
if (start == -1)
start = i;
end = i + 1;
}
}
if (start == -1) {
start = end = nslots;
} else {
g_assert (start != -1);
g_assert (start < end);
}
has_ref_regs = FALSE;
has_pin_regs = FALSE;
reg_ref_mask = 0;
reg_pin_mask = 0;
nref_regs = 0;
npin_regs = 0;
for (i = 0; i < nregs; ++i) {
gboolean has_ref = FALSE;
gboolean has_pin = FALSE;
if (!(cfg->used_int_regs & (1 << i)))
continue;
if (has_bit_set (gcfg->reg_pin_bitmap, gcfg->reg_bitmap_width, i))
has_pin = TRUE;
if (has_bit_set (gcfg->reg_ref_bitmap, gcfg->reg_bitmap_width, i))
has_ref = TRUE;
if (has_ref) {
reg_ref_mask |= (1 << i);
has_ref_regs = TRUE;
nref_regs ++;
}
if (has_pin) {
reg_pin_mask |= (1 << i);
has_pin_regs = TRUE;
npin_regs ++;
}
}
if (cfg->verbose_level > 1)
printf ("Slots: %d Start: %d End: %d Refs: %d NoRefs: %d Pin: %d Callsites: %d\n", nslots, start, end, ntypes [SLOT_REF], ntypes [SLOT_NOREF], ntypes [SLOT_PIN], ncallsites);
/* Create the GC Map */
/* The work bitmaps have one row for each slot, since this is how we access them during construction */
stack_bitmap_width = ALIGN_TO (end - start, 8) / 8;
stack_bitmap_size = stack_bitmap_width * ncallsites;
reg_ref_bitmap_width = ALIGN_TO (nref_regs, 8) / 8;
reg_ref_bitmap_size = reg_ref_bitmap_width * ncallsites;
reg_pin_bitmap_width = ALIGN_TO (npin_regs, 8) / 8;
reg_pin_bitmap_size = reg_pin_bitmap_width * ncallsites;
bitmaps_size = (has_ref_slots ? stack_bitmap_size : 0) + (has_pin_slots ? stack_bitmap_size : 0) + (has_ref_regs ? reg_ref_bitmap_size : 0) + (has_pin_regs ? reg_pin_bitmap_size : 0);
map = mono_mempool_alloc0 (cfg->mempool, sizeof (GCMap));
map->frame_reg = cfg->frame_reg;
map->start_offset = gcfg->min_offset;
map->end_offset = gcfg->min_offset + (nslots * SIZEOF_SLOT);
map->map_offset = start * SIZEOF_SLOT;
map->nslots = end - start;
map->has_ref_slots = has_ref_slots;
map->has_pin_slots = has_pin_slots;
map->has_ref_regs = has_ref_regs;
map->has_pin_regs = has_pin_regs;
g_assert (nregs < 32);
map->used_int_regs = cfg->used_int_regs;
map->reg_ref_mask = reg_ref_mask;
map->reg_pin_mask = reg_pin_mask;
map->nref_regs = nref_regs;
map->npin_regs = npin_regs;
bitmaps = mono_mempool_alloc0 (cfg->mempool, bitmaps_size);
bitmaps_offset = 0;
if (has_ref_slots) {
map->stack_ref_bitmap_offset = bitmaps_offset;
bitmaps_offset += stack_bitmap_size;
bitmap = &bitmaps [map->stack_ref_bitmap_offset];
for (i = 0; i < nslots; ++i) {
for (j = 0; j < ncallsites; ++j) {
if (get_bit (gcfg->stack_ref_bitmap, gcfg->stack_bitmap_width, i, j))
set_bit (bitmap, stack_bitmap_width, j, i - start);
}
}
}
if (has_pin_slots) {
map->stack_pin_bitmap_offset = bitmaps_offset;
bitmaps_offset += stack_bitmap_size;
bitmap = &bitmaps [map->stack_pin_bitmap_offset];
for (i = 0; i < nslots; ++i) {
for (j = 0; j < ncallsites; ++j) {
if (get_bit (gcfg->stack_pin_bitmap, gcfg->stack_bitmap_width, i, j))
set_bit (bitmap, stack_bitmap_width, j, i - start);
}
}
}
if (has_ref_regs) {
map->reg_ref_bitmap_offset = bitmaps_offset;
bitmaps_offset += reg_ref_bitmap_size;
bitmap = &bitmaps [map->reg_ref_bitmap_offset];
bindex = 0;
for (i = 0; i < nregs; ++i) {
if (reg_ref_mask & (1 << i)) {
for (j = 0; j < ncallsites; ++j) {
if (get_bit (gcfg->reg_ref_bitmap, gcfg->reg_bitmap_width, i, j))
set_bit (bitmap, reg_ref_bitmap_width, j, bindex);
}
bindex ++;
}
}
}
if (has_pin_regs) {
map->reg_pin_bitmap_offset = bitmaps_offset;
bitmaps_offset += reg_pin_bitmap_size;
bitmap = &bitmaps [map->reg_pin_bitmap_offset];
bindex = 0;
for (i = 0; i < nregs; ++i) {
if (reg_pin_mask & (1 << i)) {
for (j = 0; j < ncallsites; ++j) {
if (get_bit (gcfg->reg_pin_bitmap, gcfg->reg_bitmap_width, i, j))
set_bit (bitmap, reg_pin_bitmap_width, j, bindex);
}
bindex ++;
}
}
}
/* Call sites */
map->ncallsites = ncallsites;
if (cfg->code_len < 256)
map->callsite_entry_size = 1;
else if (cfg->code_len < 65536)
map->callsite_entry_size = 2;
else
map->callsite_entry_size = 4;
/* Encode the GC Map */
{
guint8 buf [256];
guint8 *endbuf;
GCEncodedMap *emap;
int encoded_size;
guint8 *p;
encode_gc_map (map, buf, &endbuf);
g_assert (endbuf - buf < 256);
encoded_size = endbuf - buf;
alloc_size = sizeof (GCEncodedMap) + ALIGN_TO (encoded_size, map->callsite_entry_size) + (map->callsite_entry_size * map->ncallsites) + bitmaps_size;
emap = mono_domain_alloc0 (cfg->domain, alloc_size);
//emap->ref_slots = map->ref_slots;
/* Encoded fixed fields */
p = &emap->encoded [0];
//emap->encoded_size = encoded_size;
memcpy (p, buf, encoded_size);
p += encoded_size;
/* Callsite table */
p = (guint8*)ALIGN_TO ((mgreg_t)p, map->callsite_entry_size);
if (map->callsite_entry_size == 1) {
guint8 *offsets = p;
for (i = 0; i < ncallsites; ++i)
offsets [i] = callsites [i]->pc_offset;
stats.gc_callsites8_size += ncallsites * sizeof (guint8);
} else if (map->callsite_entry_size == 2) {
guint16 *offsets = (guint16*)p;
for (i = 0; i < ncallsites; ++i)
offsets [i] = callsites [i]->pc_offset;
stats.gc_callsites16_size += ncallsites * sizeof (guint16);
} else {
guint32 *offsets = (guint32*)p;
for (i = 0; i < ncallsites; ++i)
offsets [i] = callsites [i]->pc_offset;
stats.gc_callsites32_size += ncallsites * sizeof (guint32);
}
p += ncallsites * map->callsite_entry_size;
/* Bitmaps */
memcpy (p, bitmaps, bitmaps_size);
p += bitmaps_size;
g_assert ((guint8*)p - (guint8*)emap <= alloc_size);
stats.gc_maps_size += alloc_size;
stats.gc_callsites_size += ncallsites * map->callsite_entry_size;
stats.gc_bitmaps_size += bitmaps_size;
stats.gc_map_struct_size += sizeof (GCEncodedMap) + encoded_size;
cfg->jit_info->gc_info = emap;
cfg->gc_map = (guint8*)emap;
cfg->gc_map_size = alloc_size;
}
stats.all_slots += nslots;
stats.ref_slots += ntypes [SLOT_REF];
stats.noref_slots += ntypes [SLOT_NOREF];
stats.pin_slots += ntypes [SLOT_PIN];
}
void
mini_gc_create_gc_map (MonoCompile *cfg)
{
if (!cfg->compute_gc_maps)
return;
/*
* During marking, all frames except the top frame are at a call site, and we mark the
* top frame conservatively. This means that we only need to compute and record
* GC maps for call sites.
*/
if (!(cfg->comp_done & MONO_COMP_LIVENESS))
/* Without liveness info, the live ranges are not precise enough */
return;
mono_analyze_liveness_gc (cfg);
compute_frame_size (cfg);
init_gcfg (cfg);
process_spill_slots (cfg);
process_other_slots (cfg);
process_param_area_slots (cfg);
process_variables (cfg);
process_finally_clauses (cfg);
create_map (cfg);
}
#endif /* DISABLE_JIT */
static void
parse_debug_options (void)
{
char **opts, **ptr;
const char *env;
env = g_getenv ("MONO_GCMAP_DEBUG");
if (!env)
return;
opts = g_strsplit (env, ",", -1);
for (ptr = opts; ptr && *ptr; ptr ++) {
/* No options yet */
fprintf (stderr, "Invalid format for the MONO_GCMAP_DEBUG env variable: '%s'\n", env);
exit (1);
}
g_strfreev (opts);
}
void
mini_gc_init (void)
{
MonoGCCallbacks cb;
memset (&cb, 0, sizeof (cb));
cb.thread_attach_func = thread_attach_func;
cb.thread_detach_func = thread_detach_func;
cb.thread_suspend_func = thread_suspend_func;
/* Comment this out to disable precise stack marking */
cb.thread_mark_func = thread_mark_func;
mono_gc_set_gc_callbacks (&cb);
logfile = mono_gc_get_logfile ();
parse_debug_options ();
mono_counters_register ("GC Maps size",
MONO_COUNTER_GC | MONO_COUNTER_INT, &stats.gc_maps_size);
mono_counters_register ("GC Call Sites size",
MONO_COUNTER_GC | MONO_COUNTER_INT, &stats.gc_callsites_size);
mono_counters_register ("GC Bitmaps size",
MONO_COUNTER_GC | MONO_COUNTER_INT, &stats.gc_bitmaps_size);
mono_counters_register ("GC Map struct size",
MONO_COUNTER_GC | MONO_COUNTER_INT, &stats.gc_map_struct_size);
mono_counters_register ("GC Call Sites encoded using 8 bits",
MONO_COUNTER_GC | MONO_COUNTER_INT, &stats.gc_callsites8_size);
mono_counters_register ("GC Call Sites encoded using 16 bits",
MONO_COUNTER_GC | MONO_COUNTER_INT, &stats.gc_callsites16_size);
mono_counters_register ("GC Call Sites encoded using 32 bits",
MONO_COUNTER_GC | MONO_COUNTER_INT, &stats.gc_callsites32_size);
mono_counters_register ("GC Map slots (all)",
MONO_COUNTER_GC | MONO_COUNTER_INT, &stats.all_slots);
mono_counters_register ("GC Map slots (ref)",
MONO_COUNTER_GC | MONO_COUNTER_INT, &stats.ref_slots);
mono_counters_register ("GC Map slots (noref)",
MONO_COUNTER_GC | MONO_COUNTER_INT, &stats.noref_slots);
mono_counters_register ("GC Map slots (pin)",
MONO_COUNTER_GC | MONO_COUNTER_INT, &stats.pin_slots);
mono_counters_register ("GC TLS Data size",
MONO_COUNTER_GC | MONO_COUNTER_INT, &stats.tlsdata_size);
mono_counters_register ("Stack space scanned (all)",
MONO_COUNTER_GC | MONO_COUNTER_INT, &stats.scanned_stacks);
mono_counters_register ("Stack space scanned (native)",
MONO_COUNTER_GC | MONO_COUNTER_INT, &stats.scanned_native);
mono_counters_register ("Stack space scanned (other)",
MONO_COUNTER_GC | MONO_COUNTER_INT, &stats.scanned_other);
mono_counters_register ("Stack space scanned (using GC Maps)",
MONO_COUNTER_GC | MONO_COUNTER_INT, &stats.scanned);
mono_counters_register ("Stack space scanned (precise)",
MONO_COUNTER_GC | MONO_COUNTER_INT, &stats.scanned_precisely);
mono_counters_register ("Stack space scanned (pin)",
MONO_COUNTER_GC | MONO_COUNTER_INT, &stats.scanned_conservatively);
mono_counters_register ("Stack space scanned (pin registers)",
MONO_COUNTER_GC | MONO_COUNTER_INT, &stats.scanned_registers);
}
#else
void
mini_gc_enable_gc_maps_for_aot (void)
{
}
void
mini_gc_init (void)
{
}
#ifndef DISABLE_JIT
static void
mini_gc_init_gc_map (MonoCompile *cfg)
{
}
void
mini_gc_create_gc_map (MonoCompile *cfg)
{
}
void
mini_gc_set_slot_type_from_fp (MonoCompile *cfg, int slot_offset, GCSlotType type)
{
}
void
mini_gc_set_slot_type_from_cfa (MonoCompile *cfg, int slot_offset, GCSlotType type)
{
}
#endif /* DISABLE_JIT */
#endif
#ifndef DISABLE_JIT
/*
* mini_gc_init_cfg:
*
* Set GC specific options in CFG.
*/
void
mini_gc_init_cfg (MonoCompile *cfg)
{
if (mono_gc_is_moving ()) {
cfg->disable_ref_noref_stack_slot_share = TRUE;
cfg->gen_write_barriers = TRUE;
}
mini_gc_init_gc_map (cfg);
}
#endif /* DISABLE_JIT */
/*
* Problems with the current code:
* - the stack walk is slow
* - vtypes/refs used in EH regions are treated conservatively
* - if the code is finished, less pinning will be done, causing problems because
* we promote all surviving objects to old-gen.
* - the unwind code can't handle a method stopped inside a finally region, it thinks the caller is
* another method, but in reality it is either the exception handling code or the CALL_HANDLER opcode.
* This manifests in "Unable to find ip offset x in callsite list" assertions.
* - the unwind code also can't handle frames which are in the epilog, since the unwind info is not
* precise there.
*/
/*
* Ideas for creating smaller GC maps:
* - remove empty columns from the bitmaps. This requires adding a mask bit array for
* each bitmap.
* - merge reg and stack slot bitmaps, so the unused bits at the end of the reg bitmap are
* not wasted.
* - if the bitmap width is not a multiple of 8, the remaining bits are wasted.
* - group ref and non-ref stack slots together in mono_allocate_stack_slots ().
* - add an index for the callsite table so that each entry can be encoded as a 1 byte difference
* from an index entry.
*/