Commit Graph

204 Commits

Author SHA1 Message Date
Rafael Espindola 8ca44f0b5c Implement unique sections with an unique ID.
This allows the compiler/assembly programmer to switch back to a
section. This in turn fixes the bootstrap failure on powerpc (tested
on gcc110) without changing the ppc codegen at all.

I will try to cleanup the various getELFSection overloads in a  followup patch.
Just using a default argument now would lead to ambiguities.

llvm-svn: 234099
2015-04-04 18:02:01 +00:00
David Majnemer 7db449a6e7 COFF: Let globals with private linkage reside in their own section
COFF COMDATs (for selection kinds other than 'select any') require at
least one non-section symbol in the symbol table.
Satisfy this by morally enhancing the linkage from private to internal.

Differential Revision: http://reviews.llvm.org/D8394

llvm-svn: 232570
2015-03-17 23:54:51 +00:00
David Majnemer 63b1d99943 Revert "COFF: Let globals with private linkage reside in their own section"
This reverts commit r232539.  This was committed accidently.

llvm-svn: 232543
2015-03-17 20:41:11 +00:00
David Majnemer 21fecf9441 Revert "Address review comments"
This reverts commit r232540.  This was committed accidently.

llvm-svn: 232541
2015-03-17 20:40:21 +00:00
David Majnemer 564404cc96 Address review comments
llvm-svn: 232540
2015-03-17 20:39:40 +00:00
David Majnemer 47e3842982 COFF: Let globals with private linkage reside in their own section
Summary:
COFF COMDATs (for selection kinds other than 'select any') require at
least one non-section symbol in the symbol table.
Satisfy this by morally enhancing the linkage from private to internal.

Reviewers: rafael

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D8374

llvm-svn: 232539
2015-03-17 20:39:25 +00:00
Rafael Espindola ab447e436d Put jump tables in unique sections on COFF.
If a function is going in an unique section (because of -ffunction-sections
for example), putting a jump table in .rodata will keep .rodata alive and
that will keep alive any other function that also has a jump table.

Instead, put the jump table in a unique section that is associated with the
function.

llvm-svn: 231961
2015-03-11 19:58:37 +00:00
Bruno Cardoso Lopes 618c67a018 [AsmPrinter][TLOF] 32-bit MachO support for replacing GOT equivalents
Add MachO 32-bit (i.e. arm and x86) support for replacing global GOT equivalent
symbol accesses. Unlike 64-bit targets, there's no GOTPCREL relocation, and
access through a non_lazy_symbol_pointers section is used instead.

-- before

    _extgotequiv:
       .long _extfoo

    _delta:
       .long _extgotequiv-_delta

-- after

    _delta:
       .long L_extfoo$non_lazy_ptr-_delta

       .section __IMPORT,__pointers,non_lazy_symbol_pointers
    L_extfoo$non_lazy_ptr:
       .indirect_symbol _extfoo
       .long 0

llvm-svn: 231475
2015-03-06 13:49:05 +00:00
Rafael Espindola 4491d0d337 Put jump tables in distinct sections if -ffunction-sections is used.
A small regression in r230411 was that we were basing the decision on
-fdata-sections.

llvm-svn: 230707
2015-02-26 23:55:11 +00:00
Rafael Espindola 8bc9ccc60a Support SHF_MERGE sections in COMDATs.
This patch unifies the comdat and non-comdat code paths. By doing this
it add missing features to the comdat side and removes the fixed
section assumptions from the non-comdat side.

In ELF there is no one true section for "4 byte mergeable" constants.
We are better off computing the required properties of the section
and asking the context for it.

llvm-svn: 230411
2015-02-25 00:52:15 +00:00
Rafael Espindola 9075f77064 Use short names for jumptable sections.
Also refactor code to remove some duplication.

llvm-svn: 230087
2015-02-20 23:28:28 +00:00
Rafael Espindola df19519800 Add r228939 back with a fix.
The problem in the original patch was not switching back to .text after printing
an eh table.

Original message:

On ELF, put PIC jump tables in a non executable section.

Fixes PR22558.

llvm-svn: 229586
2015-02-17 23:34:51 +00:00
Rafael Espindola 68fa249cb5 Add r228980 back.
Add support for having multiple sections with the same name and comdat.

Using this in combination with -ffunction-sections allows LLVM to output a .o
file with mulitple sections named .text. This saves space by avoiding long
unique names of the form .text.<C++ mangled name>.

llvm-svn: 229541
2015-02-17 20:48:01 +00:00
Michael Kuperstein fc3e626752 Fix quoting of #pragma comment for MS compat, LLVM part.
For #pragma comment(linker, ...) MSVC expects the comment string to be quoted, but for #pragma comment(lib, ...) the compiler itself quotes the library name.
Since this distinction disappears by the time the directive reaches the backend, move quoting for the "lib" version to the frontend.

Differential Revision: http://reviews.llvm.org/D7652

llvm-svn: 229375
2015-02-16 11:57:17 +00:00
Matthias Braun 33cc10724d Revert "On ELF, put PIC jump tables in a non executable section."
This reverts commit r228939.

The commit broke something in the output of exception handling tables on
darwin x86-64.

llvm-svn: 229203
2015-02-14 01:16:54 +00:00
Chandler Carruth d99f427e31 Revert a series of commits starting at r228886 which is triggering some
regressions for LLDB on Linux. Rafael indicated on lldb-dev that we
should just go ahead and revert these but that he wasn't at a computer.
The patches backed out are as follows:

r228980: Add support for having multiple sections with the name and ...
r228889: Invert the section relocation map.
r228888: Use the existing SymbolTableIndex intsead of doing a lookup.
r228886: Create the Section -> Rel Section map when it is first needed.

These patches look pretty nice to me, so hoping its not too hard to get
them re-instated. =D

llvm-svn: 229080
2015-02-13 07:52:39 +00:00
Rafael Espindola b6a812ebb1 Add support for having multiple sections with the same name and comdat.
Using this in combination with -ffunction-sections allows LLVM to output a .o
file with mulitple sections named .text. This saves space by avoiding long
unique names of the form .text.<C++ mangled name>.

llvm-svn: 228980
2015-02-12 23:29:51 +00:00
Rafael Espindola 203c5b9f39 On ELF, put PIC jump tables in a non executable section.
Fixes PR22558.

llvm-svn: 228939
2015-02-12 17:46:49 +00:00
Rafael Espindola 29786d4c16 Put each jump table in an independent section if the function is too.
This allows the linker to GC both, fixing pr22557.

llvm-svn: 228937
2015-02-12 17:16:46 +00:00
Rafael Espindola 25d2c20c0c Don't repeat name in comment and clang-format a function.
llvm-svn: 228831
2015-02-11 14:44:17 +00:00
Rafael Espindola f8d662aa4b Add a FIXME.
Thanks to Eric for the suggestion.

llvm-svn: 228300
2015-02-05 14:57:47 +00:00
Rafael Espindola a092f17580 Don' try to make sections in comdats SHF_MERGE.
Parts of llvm were not expecting it and we wouldn't print
the entity size of the section.

Given what comdats are used for, having SHF_MERGE sections would be
just a small improvement, so just disable it for now.

Fixes pr22463.

llvm-svn: 228196
2015-02-04 21:27:24 +00:00
Rafael Espindola ba31e27f0a Compute the ELF SectionKind from the flags.
Any code creating an MCSectionELF knows ELF and already provides the flags.

SectionKind is an abstraction used by common code that uses a plain
MCSection.

Use the flags to compute the SectionKind. This removes a lot of
guessing and boilerplate from the MCSectionELF construction.

llvm-svn: 227476
2015-01-29 17:33:21 +00:00
Rafael Espindola 093dcc43f7 Use isMergeableConst now that it is sane.
llvm-svn: 227441
2015-01-29 14:23:28 +00:00
Rafael Espindola fad3901095 Don't create multiple mergeable sections with -fdata-sections.
ELF has support for sections that can be split into fixed size or
null terminated entities.

Since these sections can be split by the linker, it is not necessary
to split them in codegen.

This reduces the combined .o size in a llvm+clang build from
202,394,570 to 173,819,098 bytes.

The time for linking clang with gold (on a VM, on a laptop) goes
from 2.250089985 to 1.383001792 seconds.

The flip side is the size of rodata in clang goes from 10,926,785
to 10,929,345 bytes.

The increase seems to be because of http://sourceware.org/bugzilla/show_bug.cgi?id=17902.

llvm-svn: 227431
2015-01-29 12:43:28 +00:00