Use isPositionIndependent(). NFC.

llvm-svn: 274005

Simplify. NFC.

Also delete out of date comment. This code was always returning .data
since r253436.

llvm-svn: 273739

IR: Introduce local_unnamed_addr attribute.

If a local_unnamed_addr attribute is attached to a global, the address
is known to be insignificant within the module. It is distinct from the
existing un

IR: Introduce local_unnamed_addr attribute.

If a local_unnamed_addr attribute is attached to a global, the address
is known to be insignificant within the module. It is distinct from the
existing unnamed_addr attribute in that it only describes a local property
of the module rather than a global property of the symbol.

This attribute is intended to be used by the code generator and LTO to allow
the linker to decide whether the global needs to be in the symbol table. It is
possible to exclude a global from the symbol table if three things are true:
- This attribute is present on every instance of the global (which means that
the normal rule that the global must have a unique address can be broken without
being observable by the program by performing comparisons against the global's
address)
- The global has linkonce_odr linkage (which means that each linkage unit must have
its own copy of the global if it requires one, and the copy in each linkage unit
must be the same)
- It is a constant or a function (which means that the program cannot observe that
the unique-address rule has been broken by writing to the global)

Although this attribute could in principle be computed from the module
contents, LTO clients (i.e. linkers) will normally need to be able to compute
this property as part of symbol resolution, and it would be inefficient to
materialize every module just to compute it.

See:
http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20160509/356401.html
http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20160516/356738.html
for earlier discussion.

Part of the fix for PR27553.

Differential Revision: http://reviews.llvm.org/D20348

llvm-svn: 272709

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Don't pass a Reloc::Model to MC.

MC only needs to know if the output is PIC or not. It never has to
decide about creating GOTs and PLTs for example. The only thing that
MC itself uses this informati

Don't pass a Reloc::Model to MC.

MC only needs to know if the output is PIC or not. It never has to
decide about creating GOTs and PLTs for example. The only thing that
MC itself uses this information for is expanding "macros" in sparc and
mips. The rest I am pretty sure could be moved to CodeGen.

This is a cleanup and isolates the code from future changes to
Reloc::Model.

llvm-svn: 269909

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[X86] Create mergeable constant pool entries for AVX

We supported creating mergeable constant pool entries for smaller
constants but not for 32-byte AVX constants.

llvm-svn: 261584

[X86] Use the correct alignment for COMDAT constant pool entries

COFF doesn't have sections with mergeable contents. Instead, each
constant pool entry ends up in a COMDAT section. The linker, when

[X86] Use the correct alignment for COMDAT constant pool entries

COFF doesn't have sections with mergeable contents. Instead, each
constant pool entry ends up in a COMDAT section. The linker, when
choosing between COMDAT sections, doesn't choose the max alignment of
the two sections. You just get whatever alignment was on the section.

If one constant needed a higher alignment in one object file from
another one, then we will get into trouble if the linker chooses the
lower alignment one.

Instead, lets promote the alignment of the constant pool entry to make
sure we don't use an under aligned constant with an instruction which
assumed otherwise.

This fixes PR26680.

llvm-svn: 261462

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Stop producing .data.rel sections.

If a section is rw, it is irrelevant if the dynamic linker will write to
it or not.

It looks like llvm implemented this because gcc was doing it. It looks
like gc

Stop producing .data.rel sections.

If a section is rw, it is irrelevant if the dynamic linker will write to
it or not.

It looks like llvm implemented this because gcc was doing it. It looks
like gcc implemented this in the hope that it would put all the
relocated items close together and speed up the dynamic linker.

There are two problem with this:
* It doesn't work. Both bfd and gold will map .data.rel to .data and
concatenate the input sections in the order they are seen.
* If we want a feature like that, it can be implemented directly in the
linker since it knowns where the dynamic relocations are.

llvm-svn: 253436

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Drop prelink support.

The way prelink used to work was

* The compiler decides if a given section only has relocations that
are know to point to the same DSO. If so, it names it
.data.rel.ro.local<s

Drop prelink support.

The way prelink used to work was

* The compiler decides if a given section only has relocations that
are know to point to the same DSO. If so, it names it
.data.rel.ro.local<something>.
* The static linker puts all of these together.
* The prelinker program assigns addresses to each library and resolves
the local relocations.

There are many problems with this:
* It is incompatible with address space randomization.
* The information passed by the compiler is redundant. The linker
knows if a given relocation is in the same DSO or not. If could sort
by that if so desired.
* There are newer ways of speeding up DSO (gnu hash for example).
* Even if we want to implement this again in the compiler, the previous
implementation is pretty broken. It talks about relocations that are
"resolved by the static linker". If they are resolved, there are none
left for the prelinker. What one needs to track is if an expression
will require only dynamic relocations that point to the same DSO.

At this point it looks like the prelinker is an historical curiosity.
For example, fedora has retired it because it failed to build for two
releases
(http://pkgs.fedoraproject.org/cgit/prelink.git/commit/?id=eb43100a8331d91c801ee3dcdb0a0bb9babfdc1f)

This patch removes support for it. That is, it stops printing the
".local" sections.

llvm-svn: 253280

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CodeGen, Target: Move Mach-O-specific symbol name logic to Mach-O lowering.

A profile of an LTO link of Chrome revealed that we were spending some
~30-50% of execution time in the function Constant:

CodeGen, Target: Move Mach-O-specific symbol name logic to Mach-O lowering.

A profile of an LTO link of Chrome revealed that we were spending some
~30-50% of execution time in the function Constant::getRelocationInfo(),
which is called from TargetLoweringObjectFile::getKindForGlobal() and in turn
from TargetMachine::getNameWithPrefix().

It turns out that we only need the result of getKindForGlobal() when
targeting Mach-O, so this change moves the relevant part of the logic to
TargetLoweringObjectFileMachO.

NFCI.

Differential Revision: http://reviews.llvm.org/D14168

llvm-svn: 252014

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Remove DataLayout from TargetLoweringObjectFile, redirect to Module

Summary:
This change is part of a series of commits dedicated to have a single
DataLayout during compilation by using always the o

Remove DataLayout from TargetLoweringObjectFile, redirect to Module

Summary:
This change is part of a series of commits dedicated to have a single
DataLayout during compilation by using always the one owned by the
module.

Reviewers: echristo

Subscribers: yaron.keren, rafael, llvm-commits, jholewinski

Differential Revision: http://reviews.llvm.org/D11079

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 242385

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Clean up redundant copies of Triple objects. NFC

Summary:

Reviewers: rengolin

Reviewed By: rengolin

Subscribers: llvm-commits, rengolin, jholewinski

Differential Revision: http://reviews.llvm.or

Clean up redundant copies of Triple objects. NFC

Summary:

Reviewers: rengolin

Reviewed By: rengolin

Subscribers: llvm-commits, rengolin, jholewinski

Differential Revision: http://reviews.llvm.org/D10382

llvm-svn: 239823

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Recommit r239721: Replace string GNU Triples with llvm::Triple in InitMCObjectFileInfo. NFC.

Summary:
This affects other tools so the previous C++ API has been retained as a
deprecated function for

Recommit r239721: Replace string GNU Triples with llvm::Triple in InitMCObjectFileInfo. NFC.

Summary:
This affects other tools so the previous C++ API has been retained as a
deprecated function for the moment. Clang has been updated with a trivial
patch (not covered by the pre-commit review) to avoid breaking -Werror builds.
Other in-tree tools will be fixed with similar patches.

This continues the patch series to eliminate StringRef forms of GNU triples
from the internals of LLVM that began in r239036.

The first time this was committed it accidentally fixed an inconsistency in
triples in llvm-mc and this caused a failure. This inconsistency was fixed in
r239808.

Reviewers: rengolin

Reviewed By: rengolin

Subscribers: llvm-commits, rengolin

Differential Revision: http://reviews.llvm.org/D10366

llvm-svn: 239812

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Revert r239721 - Replace string GNU Triples with llvm::Triple in InitMCObjectFileInfo. NFC.

It appears to cause sparc-little-endian.s to assert on Windows and Darwin.

llvm-svn: 239724

Replace string GNU Triples with llvm::Triple in InitMCObjectFileInfo. NFC.

Summary:
This affects other tools so the previous C++ API has been retained as a
deprecated function for the moment. Clang

Replace string GNU Triples with llvm::Triple in InitMCObjectFileInfo. NFC.

Summary:
This affects other tools so the previous C++ API has been retained as a
deprecated function for the moment. Clang has been updated with a trivial
patch (not covered by the pre-commit review) to avoid breaking -Werror builds.
Other in-tree tools will be fixed with similar trivial patches.

This continues the patch series to eliminate StringRef forms of GNU triples
from the internals of LLVM that began in r239036.

Reviewers: rengolin

Reviewed By: rengolin

Subscribers: llvm-commits, rengolin

Differential Revision: http://reviews.llvm.org/D10366

llvm-svn: 239721

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MC: Clean up MCExpr naming. NFC.

llvm-svn: 238634

Move alignment from MCSectionData to MCSection.

This starts merging MCSection and MCSectionData.

There are a few issues with the current split between MCSection and
MCSectionData.

* It optimizes t

Move alignment from MCSectionData to MCSection.

This starts merging MCSection and MCSectionData.

There are a few issues with the current split between MCSection and
MCSectionData.

* It optimizes the the not as important case. We want the production
of .o files to be really fast, but the split puts the information used
for .o emission in a separate data structure.

* The ELF/COFF/MachO hierarchy is not represented in MCSectionData,
leading to some ad-hoc ways to represent the various flags.

* It makes it harder to remember where each item is.

The attached patch starts merging the two by moving the alignment from
MCSectionData to MCSection.

Most of the patch is actually just dropping 'const', since
MCSectionData is mutable, but MCSection was not.

llvm-svn: 237936

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MC: Clean up method names in MCContext.

The naming was a mish-mash of old and new style. Update to be consistent
with the new. NFC.

llvm-svn: 237594

Remove superfluous .str() and replace std::string concatenation with Twine.

llvm-svn: 233392

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 thi

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

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Revert "COFF: Let globals with private linkage reside in their own section"

This reverts commit r232539. This was committed accidently.

llvm-svn: 232543

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.
Sa

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

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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

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

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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: 229

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

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

Fixes PR22558.

llvm-svn: 228939

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