From 0c73bb07e6c88a40528f4fb088075a99ac9ec3a5 Mon Sep 17 00:00:00 2001
From: David Anderson <danderson@mozilla.com>
Date: Fri, 28 May 2010 00:30:35 -0700
Subject: [PATCH] [JAEGER] Jumps in-between the slow and fast paths now work.

---
 js/src/methodjit/Compiler.cpp     |  9 ++++---
 js/src/methodjit/StubCompiler.cpp | 39 +++++++++++++++++++++++--------
 js/src/methodjit/StubCompiler.h   | 10 +++++---
 3 files changed, 42 insertions(+), 16 deletions(-)

diff --git a/js/src/methodjit/Compiler.cpp b/js/src/methodjit/Compiler.cpp
index 6f1ccd20652..9acf069550a 100644
--- a/js/src/methodjit/Compiler.cpp
+++ b/js/src/methodjit/Compiler.cpp
@@ -195,7 +195,10 @@ mjit::Compiler::finishThisUp()
     memcpy(result, masm.buffer(), masm.size());
     memcpy(result + masm.size(), stubcc.buffer(), stubcc.size());
 
-    /* Patch up stub calls. */
+    /* Link fast and slow paths together. */
+    stubcc.fixCrossJumps(result, masm.size(), masm.size() + stubcc.size());
+
+    /* Patch all outgoing calls. */
     masm.finalize(result);
     stubcc.finalize(result + masm.size());
 
@@ -449,7 +452,7 @@ mjit::Compiler::emitReturn()
 void
 mjit::Compiler::prepareStubCall()
 {
-    JaegerSpew(JSpew_Insns, " ---- SLOW CALL, SYNCING FRAME ---- \n");
+    JaegerSpew(JSpew_Insns, " ---- STUB CALL, SYNCING FRAME ---- \n");
     frame.sync();
     JaegerSpew(JSpew_Insns, " ---- KILLING TEMP REGS ---- \n");
     frame.killSyncedRegs(Registers::TempRegs);
@@ -462,7 +465,7 @@ mjit::Compiler::stubCall(void *ptr, Uses uses, Defs defs)
     frame.forget(uses.nuses);
     JaegerSpew(JSpew_Insns, " ---- CALLING STUB ---- \n");
     Call cl = masm.stubCall(ptr, PC, frame.stackDepth() + script->nfixed);
-    JaegerSpew(JSpew_Insns, " ---- END SLOW CALL ---- \n");
+    JaegerSpew(JSpew_Insns, " ---- END STUB CALL ---- \n");
     return cl;
 }
 
diff --git a/js/src/methodjit/StubCompiler.cpp b/js/src/methodjit/StubCompiler.cpp
index 69e9323e956..494f5ea2b67 100644
--- a/js/src/methodjit/StubCompiler.cpp
+++ b/js/src/methodjit/StubCompiler.cpp
@@ -40,37 +40,43 @@
 
 #include "StubCompiler.h"
 #include "Compiler.h"
+#include "assembler/assembler/LinkBuffer.h"
 
 using namespace js;
 using namespace mjit;
 
 StubCompiler::StubCompiler(JSContext *cx, mjit::Compiler &cc, FrameState &frame, JSScript *script)
-  : cx(cx), cc(cc), frame(frame), script(script), exits(SystemAllocPolicy())
+  : cx(cx), cc(cc), frame(frame), script(script), exits(SystemAllocPolicy()),
+    joins(SystemAllocPolicy())
 {
 }
 
 void
 StubCompiler::linkExit(Jump j)
 {
-    /* :TODO: oom check */
-    exits.append(ExitPatch(j, masm.label()));
+    exits.append(CrossPatch(j, masm.label()));
 }
 
 void
 StubCompiler::leave()
 {
-    JaegerSpew(JSpew_Insns, " ---- BEGIN STUB SPILL CODE ---- \n");
+    JaegerSpew(JSpew_Insns, " ---- BEGIN SLOW SPILL CODE ---- \n");
     frame.sync(masm, snapshot);
-    JaegerSpew(JSpew_Insns, " ---- END STUB SPILL CODE ---- \n");
-    JaegerSpew(JSpew_Insns, " ---- BEGIN STUB CALL CODE ---- \n");
+    JaegerSpew(JSpew_Insns, " ---- END SLOW SPILL CODE ---- \n");
+    JaegerSpew(JSpew_Insns, " ---- BEGIN SLOW CALL CODE ---- \n");
 }
 
 void
 StubCompiler::rejoin(uint32 invalidationDepth)
 {
-    JaegerSpew(JSpew_Insns, " ---- BEGIN STUB RESTORE CODE ---- \n");
+    JaegerSpew(JSpew_Insns, " ---- BEGIN SLOW RESTORE CODE ---- \n");
+
     frame.merge(masm, snapshot, invalidationDepth);
-    JaegerSpew(JSpew_Insns, " ---- END STUB RESTORE CODE ---- \n");
+
+    Jump j = masm.jump();
+    joins.append(CrossPatch(j, cc.getLabel()));
+
+    JaegerSpew(JSpew_Insns, " ---- END SLOW RESTORE CODE ---- \n");
 }
 
 typedef JSC::MacroAssembler::RegisterID RegisterID;
@@ -81,12 +87,25 @@ JSC::MacroAssembler::Call
 StubCompiler::stubCall(void *ptr)
 {
     Call cl = masm.stubCall(ptr, cc.getPC(), frame.stackDepth() + script->nfixed);
-    JaegerSpew(JSpew_Insns, " ---- END STUB CALL CODE ---- \n");
+    JaegerSpew(JSpew_Insns, " ---- END SLOW CALL CODE ---- \n");
     return cl;
 }
 
 void
-StubCompiler::finalize(uint8* ncode)
+StubCompiler::fixCrossJumps(uint8 *ncode, size_t offset, size_t total)
+{
+    JSC::LinkBuffer fast(ncode, total);
+    JSC::LinkBuffer slow(ncode + offset, total - offset);
+
+    for (size_t i = 0; i < exits.length(); i++)
+        fast.link(exits[i].from, slow.locationOf(exits[i].to));
+
+    for (size_t i = 0; i < joins.length(); i++)
+        slow.link(joins[i].from, fast.locationOf(joins[i].to));
+}
+
+void
+StubCompiler::finalize(uint8 *ncode)
 {
     masm.finalize(ncode);
 }
diff --git a/js/src/methodjit/StubCompiler.h b/js/src/methodjit/StubCompiler.h
index 083f55055f9..4f7a622c880 100644
--- a/js/src/methodjit/StubCompiler.h
+++ b/js/src/methodjit/StubCompiler.h
@@ -58,8 +58,8 @@ class StubCompiler
     typedef JSC::MacroAssembler::Jump Jump;
     typedef JSC::MacroAssembler::Label Label;
 
-    struct ExitPatch {
-        ExitPatch(Jump from, Label to)
+    struct CrossPatch {
+        CrossPatch(Jump from, Label to)
           : from(from), to(to)
         { }
 
@@ -72,9 +72,12 @@ class StubCompiler
     FrameState &frame;
     JSScript *script;
     Assembler masm;
-    Vector<ExitPatch, 64, SystemAllocPolicy> exits;
     RegSnapshot snapshot;
 
+    /* :TODO: oom check */
+    Vector<CrossPatch, 64, SystemAllocPolicy> exits;
+    Vector<CrossPatch, 64, SystemAllocPolicy> joins;
+
   public:
     StubCompiler(JSContext *cx, mjit::Compiler &cc, FrameState &frame, JSScript *script);
 
@@ -112,6 +115,7 @@ class StubCompiler
     void rejoin(uint32 invalidationDepth);
 
     /* Finish all native code patching. */
+    void fixCrossJumps(uint8 *ncode, size_t offset, size_t total);
     void finalize(uint8 *ncode);
 
   private: