Revert "Disable the fix for pr20793 because of a gnu ld bug."

This reverts commit r217211.

Both the bfd ld and gold outputs were valid. They were using a Rela relocation,
so the value present in th

Revert "Disable the fix for pr20793 because of a gnu ld bug."

This reverts commit r217211.

Both the bfd ld and gold outputs were valid. They were using a Rela relocation,
so the value present in the relocated location was not used, which caused me
to misread the output.

llvm-svn: 217264

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Disable the fix for pr20793 because of a gnu ld bug.

llvm-svn: 217211

Refactor to avoid code duplication. NFC.

llvm-svn: 217207

Fix pr20793.

With this patch the third field of llvm.global_ctors is also used on ELF.

llvm-svn: 217202

MC Win64: Put unwind info for COMDAT code into the same COMDAT group

Summary:
This fixes a long standing issue where we would emit many little .text
sections and only one .pdata and .xdata section.

MC Win64: Put unwind info for COMDAT code into the same COMDAT group

Summary:
This fixes a long standing issue where we would emit many little .text
sections and only one .pdata and .xdata section. Now we generate one
.pdata / .xdata pair per .text section and associate them correctly.

Fixes PR19667.

Reviewers: majnemer

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D5181

llvm-svn: 217176

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On MachO, don't put non-private constants in mergeable sections.

On MachO, putting a symbol that doesn't start with a 'L' or 'l' in one of the
__TEXT,__literal* sections prevents the linker from mer

On MachO, don't put non-private constants in mergeable sections.

On MachO, putting a symbol that doesn't start with a 'L' or 'l' in one of the
__TEXT,__literal* sections prevents the linker from merging the context of the
section.

Since private GVs are the ones the get mangled to start with 'L' or 'l', we now
only put those on the __TEXT,__literal* sections.

llvm-svn: 216682

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Remove the TargetMachine forwards for TargetSubtargetInfo based
information and update all callers. No functional change.

llvm-svn: 214781

CodeGen: Stick constant pool entries in COMDAT sections for WinCOFF

COFF lacks a feature that other object file formats support: mergeable
sections.

To work around this, MSVC sticks constant pool e

CodeGen: Stick constant pool entries in COMDAT sections for WinCOFF

COFF lacks a feature that other object file formats support: mergeable
sections.

To work around this, MSVC sticks constant pool entries in special COMDAT
sections so that each constant is in it's own section. This permits
unused constants to be dropped and it also allows duplicate constants in
different translation units to get merged together.

This fixes PR20262.

Differential Revision: http://reviews.llvm.org/D4482

llvm-svn: 213006

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Make helper functions static.

llvm-svn: 212460

IR: Add COMDATs to the IR

This new IR facility allows us to represent the object-file semantic of
a COMDAT group.

COMDATs allow us to tie together sections and make the inclusion of one
dependent o

IR: Add COMDATs to the IR

This new IR facility allows us to represent the object-file semantic of
a COMDAT group.

COMDATs allow us to tie together sections and make the inclusion of one
dependent on another. This is required to implement features like MS
ABI VFTables and optimizing away certain kinds of initialization in C++.

This functionality is only representable in COFF and ELF, Mach-O has no
similar mechanism.

Differential Revision: http://reviews.llvm.org/D4178

llvm-svn: 211920

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CodeGen: Avoid multiple strlen calls

Use a StringRef to hold our section prefix. This avoids multiple calls
to strlen.

llvm-svn: 211602

Fix a few issues with comdat handling on COFF.

* Section association cannot use just the section name as many
sections can have the same name. With this patch, the comdat symbol in
an assoc section

Fix a few issues with comdat handling on COFF.

* Section association cannot use just the section name as many
sections can have the same name. With this patch, the comdat symbol in
an assoc section is interpreted to mean a symbol in the associated
section and the mapping is discovered from it.

* Comdat symbols were not being set correctly. Instead we were getting
whatever was output first for that section.

A consequence is that associative sections now must use .section to
set the association. Using .linkonce would not work since it is not
possible to change a sections comdat symbol (it is used to decide if
we should create a new section or reuse an existing one).

This includes r210298, which was reverted because it was asserting
on an associated section having the same comdat as the associated
section.

llvm-svn: 210367

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Fix MIPS exception personality encoding.

For MIPS, we have to encode the personality routine with
an indirect pointer to absptr; otherwise, some link warning
warning will be raised, and the program

Fix MIPS exception personality encoding.

For MIPS, we have to encode the personality routine with
an indirect pointer to absptr; otherwise, some link warning
warning will be raised, and the program might crash in some
early MIPS Android device.

llvm-svn: 209907

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Add comdat key field to llvm.global_ctors and llvm.global_dtors

This allows us to put dynamic initializers for weak data into the same
comdat group as the data being initialized. This is necessary

Add comdat key field to llvm.global_ctors and llvm.global_dtors

This allows us to put dynamic initializers for weak data into the same
comdat group as the data being initialized. This is necessary for MSVC
ABI compatibility. Once we have comdats for guard variables, we can use
the combination to help GlobalOpt fire more often for weak data with
guarded initialization on other platforms.

Reviewers: nlewycky

Differential Revision: http://reviews.llvm.org/D3499

llvm-svn: 209015

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[C++11] More 'nullptr' conversion. In some cases just using a boolean check instead of comparing to nullptr.

llvm-svn: 206142

WinCOFF: Emit common symbols as specified in the COFF spec

Summary:
Local common symbols were properly inserted into the .bss section.
However, putting external common symbols in the .bss section wo

WinCOFF: Emit common symbols as specified in the COFF spec

Summary:
Local common symbols were properly inserted into the .bss section.
However, putting external common symbols in the .bss section would give
them a strong definition.

Instead, encode them as undefined, external symbols who's symbol value
is equivalent to their size.

Reviewers: Bigcheese, rafael, rnk

CC: llvm-commits

Differential Revision: http://reviews.llvm.org/D3324

llvm-svn: 205811

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WinCOFF: Add support for -fdata-sections

This is a pretty straight forward translation for COFF, we just need to
stick the data in a COMDAT section marked as
IMAGE_COMDAT_SELECT_NODUPLICATES.

N.B.

WinCOFF: Add support for -fdata-sections

This is a pretty straight forward translation for COFF, we just need to
stick the data in a COMDAT section marked as
IMAGE_COMDAT_SELECT_NODUPLICATES.

N.B. We must be careful to avoid sticking entities with private linkage
in COMDAT groups. COFF is pretty hostile to the renaming of entities so
we must be careful to disallow GlobalVariables with unstable names.

llvm-svn: 204703

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WinCOFF: Add support for -ffunction-sections

This is a pretty straight forward translation for COFF, we just need to
stick the function in a COMDAT section marked as
IMAGE_COMDAT_SELECT_NODUPLICATES

WinCOFF: Add support for -ffunction-sections

This is a pretty straight forward translation for COFF, we just need to
stick the function in a COMDAT section marked as
IMAGE_COMDAT_SELECT_NODUPLICATES.

llvm-svn: 204565

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MC: Remove superfluous section attribute flag definitions

Summary:
llvm/MC/MCSectionMachO.h and llvm/Support/MachO.h both had the same
definitions for the section flags. Instead, grab the definitio

MC: Remove superfluous section attribute flag definitions

Summary:
llvm/MC/MCSectionMachO.h and llvm/Support/MachO.h both had the same
definitions for the section flags. Instead, grab the definitions out of
support.

No functionality change.

Reviewers: grosbach, Bigcheese, rafael

Reviewed By: rafael

CC: llvm-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D2998

llvm-svn: 203211

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Remove shouldEmitUsedDirectiveFor.

Clang now uses llvm.compiler.used for these cases.

llvm-svn: 203174

[cleanup] Re-sort all the includes with utils/sort_includes.py.

llvm-svn: 202811

move getNameWithPrefix and getSymbol to TargetMachine.

TargetLoweringBase is implemented in CodeGen, so before this patch we had
a dependency fom Target to CodeGen. This would show up as a link fail

move getNameWithPrefix and getSymbol to TargetMachine.

TargetLoweringBase is implemented in CodeGen, so before this patch we had
a dependency fom Target to CodeGen. This would show up as a link failure of
llvm-stress when building with -DBUILD_SHARED_LIBS=ON.

This fixes pr18900.

llvm-svn: 201711

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Add back r201608, r201622, r201624 and r201625

r201608 made llvm corretly handle private globals with MachO. r201622 fixed
a bug in it and r201624 and r201625 were changes for using private linkage,

Add back r201608, r201622, r201624 and r201625

r201608 made llvm corretly handle private globals with MachO. r201622 fixed
a bug in it and r201624 and r201625 were changes for using private linkage,
assuming that llvm would do the right thing.

They all got reverted because r201608 introduced a crash in LTO. This patch
includes a fix for that. The issue was that TargetLoweringObjectFile now has
to be initialized before we can mangle names of private globals. This is
trivially true during the normal codegen pipeline (the asm printer does it),
but LTO has to do it manually.

llvm-svn: 201700

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Revert r201622 and r201608.

This causes the LLVMgold plugin to segfault. More information on the
replies to r201608.

llvm-svn: 201669

Avoid an infinite cycle with private linkage and -f{data|function}-sections.

When outputting an object we check its section to find its name, but when
looking for the section with -ffunction-section

Avoid an infinite cycle with private linkage and -f{data|function}-sections.

When outputting an object we check its section to find its name, but when
looking for the section with -ffunction-section we look for the symbol name.

Break the loop by requesting a name with the private prefix when constructing
the section name. This matches the behavior before r201608.

llvm-svn: 201622

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