[MC][ARM] Don't create multiple .ARM.exidx associated to one .text

Fixed an issue exposed by D74006.

In clang cc1as, MCContext::UseNamesOnTempLabels is true.
When parsing a .fnstart directive, FnSt

[MC][ARM] Don't create multiple .ARM.exidx associated to one .text

Fixed an issue exposed by D74006.

In clang cc1as, MCContext::UseNamesOnTempLabels is true.
When parsing a .fnstart directive, FnStart gets redefined to a temporary symbol of a different name (.Ltmp0, .Ltmp1, ...).
MCContext::getELFSection() called by SwitchToEHSection() will create a different .ARM.exidx each time.

llvm-mc uses `Ctx.setUseNamesOnTempLabels(false);` and FnStart is unnamed.
MCContext::getELFSection() called by SwitchToEHSection() will reuse the same .ARM.exidx .

Reviewed By: efriedma

Differential Revision: https://reviews.llvm.org/D75095

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[MC] Add MCSection::NonUniqueID and delete one MCContext::getELFSection overload

[MC][ELF] Make linked-to symbol name part of ELFSectionKey

https://bugs.llvm.org/show_bug.cgi?id=44775

This rule has been implemented by GNU as https://sourceware.org/ml/binutils/2020-02/msg00028.h

[MC][ELF] Make linked-to symbol name part of ELFSectionKey

https://bugs.llvm.org/show_bug.cgi?id=44775

This rule has been implemented by GNU as https://sourceware.org/ml/binutils/2020-02/msg00028.html (binutils >= 2.35)

It allows us to simplify

```
.section .foo,"o",foo,unique,0
.section .foo,"o",bar,unique,1 # different section
```

to

```
.section .foo,"o",foo
.section .foo,"o",bar # different section
```

We consider the two `.foo` different even if the linked-to symbols foo and bar
are defined in the same section. This is a deliberate choice so that we don't
need to know the section where foo and bar are defined beforehand.

Differential Revision: https://reviews.llvm.org/D74006

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[MC] De-capitalize some MCStreamer::Emit* functions

[MC][ELF] Rename MC related "Associated" to "LinkedToSym"

"linked-to section" is used by the ELF spec. By analogy, "linked-to
symbol" is a good name for the signature symbol. The word "linked-to"
i

[MC][ELF] Rename MC related "Associated" to "LinkedToSym"

"linked-to section" is used by the ELF spec. By analogy, "linked-to
symbol" is a good name for the signature symbol. The word "linked-to"
implies a directed edge and makes it clear its relation with "sh_link",
while one can argue that "associated" means an undirected edge.

Also, combine tests and add precise SMLoc to improve diagnostics.

Reviewed By: eugenis, grimar, jhenderson

Differential Revision: https://reviews.llvm.org/D74082

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Make llvm::StringRef to std::string conversions explicit.

This is how it should've been and brings it more in line with
std::string_view. There should be no functional change here.

This is mostly m

Make llvm::StringRef to std::string conversions explicit.

This is how it should've been and brings it more in line with
std::string_view. There should be no functional change here.

This is mostly mechanical from a custom clang-tidy check, with a lot of
manual fixups. It uncovers a lot of minor inefficiencies.

This doesn't actually modify StringRef yet, I'll do that in a follow-up.

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[XCOFF][AIX] Differentiate usage of label symbol and csect symbol

Summary:
We are using symbols to represent label and csect interchangeably before, and that could be a problem.
There are cases we

[XCOFF][AIX] Differentiate usage of label symbol and csect symbol

Summary:
We are using symbols to represent label and csect interchangeably before, and that could be a problem.
There are cases we would need to add storage mapping class to the symbol if that symbol is actually the name of a csect, but it's hard for us to figure out whether that symbol is a label or csect.

This patch intend to do the following:
1. Construct a QualName (A name include the storage mapping class)
MCSymbolXCOFF for every MCSectionXCOFF.
2. Keep a pointer to that QualName inside of MCSectionXCOFF.
3. Use that QualName whenever we need a symbol refers to that
MCSectionXCOFF.
4. Adapt the snowball effect from the above changes in
XCOFFObjectWriter.cpp.

Reviewers: xingxue, DiggerLin, sfertile, daltenty, hubert.reinterpretcast

Reviewed By: DiggerLin, daltenty

Subscribers: wuzish, nemanjai, mgorny, hiraditya, kbarton, jsji, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D69633

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Adds support for writing the .bss section for XCOFF object files.

Adds Wrapper classes for MCSymbol and MCSection into the XCOFF target
object writer. Also adds a class to represent the top-level se

Adds support for writing the .bss section for XCOFF object files.

Adds Wrapper classes for MCSymbol and MCSection into the XCOFF target
object writer. Also adds a class to represent the top-level sections, which we
materialize in the ObjectWriter.

executePostLayoutBinding will map all csects into the appropriate
container depending on its storage mapping class, and map all symbols
into their containing csect. Once all symbols have been processed we
- Assign addresses and symbol table indices.
- Calaculte section sizes.
- Build the section header table.
- Assign the sections raw-pointer value for non-virtual sections.

Since the .bss section is virtual, writing the header table is enough to
add support. Writing of a sections raw data, or of any relocations is
not included in this patch.

Testing is done by dumping the section header table, but it needs to be
extended to include dumping the symbol table once readobj support for
dumping auxiallary entries lands.

Differential Revision: https://reviews.llvm.org/D65159

llvm-svn: 369454

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[MC] Don't recreate a label if it's already used

Summary:
This patch keeps track of MCSymbols created for blocks that were
referenced in inline asm. It prevents creating a new symbol which
doesn't r

[MC] Don't recreate a label if it's already used

Summary:
This patch keeps track of MCSymbols created for blocks that were
referenced in inline asm. It prevents creating a new symbol which
doesn't refer to the block.

Inline asm may have a reference to a label. The asm parser however
doesn't recognize it as a label and tries to create a new symbol. The
result being that instead of the original symbol (e.g. ".Ltmp0") the
parser replaces it in the inline asm with the new one (e.g. ".Ltmp00")
without updating it in the symbol table. So the machine basic block
retains the "old" symbol (".Ltmp0"), but the inline asm uses the new one
(".Ltmp00").

Reviewers: nickdesaulniers, craig.topper

Subscribers: nathanchance, javed.absar, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D65304

llvm-svn: 368477

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[llvm-mc] Add reportWarning() to MCContext

Adding reportWarning() to MCContext, so that it can be used from
the Hexagon assembler backend.

llvm-svn: 368327

Stubs out TLOF for AIX and add support for common vars in assembly output.

Stubs out a TargetLoweringObjectFileXCOFF class, implementing only
SelectSectionForGlobal for common symbols. Also adds an

Stubs out TLOF for AIX and add support for common vars in assembly output.

Stubs out a TargetLoweringObjectFileXCOFF class, implementing only
SelectSectionForGlobal for common symbols. Also adds an override of
EmitGlobalVariable in PPCAIXAsmPrinter which adds a number of defensive errors
and adds support for emitting common globals.

llvm-svn: 366727

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Boilerplate for producing XCOFF object files from the PowerPC backend.

Stubs out a number of the classes needed to produce a new object file format
(XCOFF) for the powerpc-aix target. For testing in

Boilerplate for producing XCOFF object files from the PowerPC backend.

Stubs out a number of the classes needed to produce a new object file format
(XCOFF) for the powerpc-aix target. For testing input is an empty module which
produces an object file with just a file header.

Differential Revision: https://reviews.llvm.org/D61694

llvm-svn: 365541

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MCContext: Delete unused functions

llvm-svn: 363674

[AIX] Implement function descriptor on SDAG

Summary:
(1) Function descriptor on AIX
On AIX, a called routine may have 2 distinct symbols associated with it:
* A function descriptor (Name)
* A func

[AIX] Implement function descriptor on SDAG

Summary:
(1) Function descriptor on AIX
On AIX, a called routine may have 2 distinct symbols associated with it:
* A function descriptor (Name)
* A function entry point (.Name)

The descriptor structure on AIX is the same as those in the ELF V1 ABI:
* The address of the entry point of the function.
* The TOC base address for the function.
* The environment pointer.

The descriptor symbol uses the same name as the source level function in C.
The function entry point is analogous to the symbol we would generate for a
function in a non-descriptor-based ABI, except that it is renamed by
prepending a ".".

Which symbol gets referenced depends on the context:
* Taking the address of the function references the descriptor symbol.
* Calling the function references the entry point symbol.

(2) Speaking of implementation on AIX, for direct function call target, we
create proper MCSymbol SDNode(e.g . ".foo") while constructing SDAG to
replace original TargetGlobalAddress SDNode. Then down the path, we can
take advantage of this MCSymbol.

Patch by: Xiangling_L

Reviewed by: sfertile, hubert.reinterpretcast, jasonliu, syzaara

Differential Revision: https://reviews.llvm.org/D62532

llvm-svn: 362735

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[DebugInfo] Handle -main-file-name correctly for asm source.
This option provides only the base filename, not a full relative path.

Part of the fix for PR41839.

Differential Revision: https://revie

[DebugInfo] Handle -main-file-name correctly for asm source.
This option provides only the base filename, not a full relative path.

Part of the fix for PR41839.

Differential Revision: https://reviews.llvm.org/D62071

llvm-svn: 361245

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[llvm] Prevent duplicate files in debug line header in dwarf 5: another attempt

Another attempt to land the changes in debug line header to prevent duplicate
files in Dwarf 5. I rolled back my previ

[llvm] Prevent duplicate files in debug line header in dwarf 5: another attempt

Another attempt to land the changes in debug line header to prevent duplicate
files in Dwarf 5. I rolled back my previous commit because of a mistake in
generating the object file in a test. Meanwhile, I addressed some offline
comments and changed the implementation; the largest difference is that
MCDwarfLineTableHeader does not keep DwarfVersion but gets it as a parameter. I
also merged the patch to fix two lld tests that will strt to fail into this
patch.

Original Commit:

https://reviews.llvm.org/D59515

Original Message:
Motivation: In previous dwarf versions, file name indexes started from 1, and
the primary source file was not explicit. Dwarf 5 standard (6.2.4) prescribes
the primary source file to be explicitly given an entry with an index number 0.

The current implementation honors the specification by just duplicating the
main source file, once with index number 0, and later maybe with another
index number. While this is compliant with the letter of the standard, the
duplication causes problems for consumers of this information such as lldb.
(Some files are duplicated, where only some of them have a line table although
all refer to the same file)

With this change, dwarf 5 debug line section files always start from 0, and
the zeroth entry is not duplicated whenever possible. This requires different
handling of dwarf 4 and dwarf 5 during generation (e.g. when a function returns
an index zero for a file name, it signals an error in dwarf 4, but not in dwarf
5) However, I think the minor complication is worth it, because it enables all
consumers (lldb, gdb, dwarfdump, objdump, and so on) to treat all files in the
file name list homogenously.

llvm-svn: 358732

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NFC: Move API uses of MD5::MD5Result to Optional rather than a pointer.

Differential Revision: https://reviews.llvm.org/D60290

llvm-svn: 357736

Revert "[llvm] Reapply "Prevent duplicate files in debug line header in dwarf 5.""

This reverts commit rL357020.

The commit broke the test llvm/test/tools/llvm-objdump/embedded-source.test
on some

Revert "[llvm] Reapply "Prevent duplicate files in debug line header in dwarf 5.""

This reverts commit rL357020.

The commit broke the test llvm/test/tools/llvm-objdump/embedded-source.test
on some builds including clang-ppc64be-linux-multistage,
clang-s390x-linux, clang-with-lto-ubuntu, clang-x64-windows-msvc,
llvm-clang-lld-x86_64-scei-ps4-windows10pro-fast (and others).

llvm-svn: 357026

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[llvm] Reapply "Prevent duplicate files in debug line header in dwarf 5."

Reapply rL356941 after regenerating the object file in the failing test
llvm/test/tools/llvm-objdump/embedded-source.test fr

[llvm] Reapply "Prevent duplicate files in debug line header in dwarf 5."

Reapply rL356941 after regenerating the object file in the failing test
llvm/test/tools/llvm-objdump/embedded-source.test from source.

Original commit message:

[llvm] Prevent duplicate files in debug line header in dwarf 5.

Motivation: In previous dwarf versions, file name indexes started from 1, and
the primary source file was not explicit. Dwarf 5 standard (6.2.4) prescribes
the primary source file to be explicitly given an entry with an index number 0.

The current implementation honors the specification by just duplicating the
main source file, once with index number 0, and later maybe with another
index number. While this is compliant with the letter of the standard, the
duplication causes problems for consumers of this information such as lldb.
(Some files are duplicated, where only some of them have a line table although
all refer to the same file)

With this change, dwarf 5 debug line section files always start from 0, and
the zeroth entry is not duplicated whenever possible. This requires different
handling of dwarf 4 and dwarf 5 during generation (e.g. when a function returns
an index zero for a file name, it signals an error in dwarf 4, but not in dwarf 5)
However, I think the minor complication is worth it, because it enables all
consumers (lldb, gdb, dwarfdump, objdump, and so on) to treat all files in the
file name list homogenously.

Tags: #llvm, #debug-info

Differential Revision: https://reviews.llvm.org/D59515

llvm-svn: 357018

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Revert "[llvm] Prevent duplicate files in debug line header in dwarf 5."

This reverts commit 312ab05887d0e2caa29aaf843cefe39379a98d36.

My commit broke the build; I will revert and find out what hap

Revert "[llvm] Prevent duplicate files in debug line header in dwarf 5."

This reverts commit 312ab05887d0e2caa29aaf843cefe39379a98d36.

My commit broke the build; I will revert and find out what happened.

llvm-svn: 356951

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[llvm] Prevent duplicate files in debug line header in dwarf 5.

Summary:

Motivation: In previous dwarf versions, file name indexes started from 1, and
the primary source file was not explicit. Dwar

[llvm] Prevent duplicate files in debug line header in dwarf 5.

Summary:

Motivation: In previous dwarf versions, file name indexes started from 1, and
the primary source file was not explicit. Dwarf 5 standard (6.2.4) prescribes
the primary source file to be explicitly given an entry with an index number 0.

The current implementation honors the specification by just duplicating the
main source file, once with index number 0, and later maybe with another
index number. While this is compliant with the letter of the standard, the
duplication causes problems for consumers of this information such as lldb.
(Some files are duplicated, where only some of them have a line table although
all refer to the same file)

With this change, dwarf 5 debug line section files always start from 0, and
the zeroth entry is not duplicated whenever possible. This requires different
handling of dwarf 4 and dwarf 5 during generation (e.g. when a function returns
an index zero for a file name, it signals an error in dwarf 4, but not in dwarf 5)
However, I think the minor complication is worth it, because it enables all
consumers (lldb, gdb, dwarfdump, objdump, and so on) to treat all files in the
file name list homogenously.

Reviewers: dblaikie, probinson, aprantl, espindola

Reviewed By: probinson

Subscribers: emaste, jvesely, nhaehnle, aprantl, javed.absar, arichardson, hiraditya, MaskRay, rupprecht, jdoerfert, llvm-commits

Tags: #llvm, #debug-info

Differential Revision: https://reviews.llvm.org/D59515

llvm-svn: 356941

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Add XCOFF triple object format type for AIX

This patch adds an XCOFF triple object format type into LLVM.
This XCOFF triple object file type will be used later by object file and assembly generation

Add XCOFF triple object format type for AIX

This patch adds an XCOFF triple object format type into LLVM.
This XCOFF triple object file type will be used later by object file and assembly generation for the AIX platform.

Differential Revision: https://reviews.llvm.org/D58930

llvm-svn: 355989

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Try to fix Windows bots after r355226.

Windows has two path separator characters.

llvm-svn: 355235

[DWARF] Make -g with empty assembler source work better.

This was sometimes causing clang or llvm-mc to crash, and in other
cases could emit a bogus DWARF line-table header. I did an interim
patch i

[DWARF] Make -g with empty assembler source work better.

This was sometimes causing clang or llvm-mc to crash, and in other
cases could emit a bogus DWARF line-table header. I did an interim
patch in r352541; this patch should be a cleaner and more complete
fix, and retains the test.

Addresses PR40538.

Differential Revision: https://reviews.llvm.org/D58750

llvm-svn: 355226

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Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the ne

Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636

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