[Coverage] Revise format to reduce binary size

Revise the coverage mapping format to reduce binary size by:

1. Naming function records and marking them `linkonce_odr`, and
2. Compressing filenames.

[Coverage] Revise format to reduce binary size

Revise the coverage mapping format to reduce binary size by:

1. Naming function records and marking them `linkonce_odr`, and
2. Compressing filenames.

This shrinks the size of llc's coverage segment by 82% (334MB -> 62MB)
and speeds up end-to-end single-threaded report generation by 10%. For
reference the compressed name data in llc is 81MB (__llvm_prf_names).

Rationale for changes to the format:

- With the current format, most coverage function records are discarded.
E.g., more than 97% of the records in llc are *duplicate* placeholders
for functions visible-but-not-used in TUs. Placeholders *are* used to
show under-covered functions, but duplicate placeholders waste space.

- We reached general consensus about giving (1) a try at the 2017 code
coverage BoF [1]. The thinking was that using `linkonce_odr` to merge
duplicates is simpler than alternatives like teaching build systems
about a coverage-aware database/module/etc on the side.

- Revising the format is expensive due to the backwards compatibility
requirement, so we might as well compress filenames while we're at it.
This shrinks the encoded filenames in llc by 86% (12MB -> 1.6MB).

See CoverageMappingFormat.rst for the details on what exactly has
changed.

Fixes PR34533 [2], hopefully.

[1] http://lists.llvm.org/pipermail/llvm-dev/2017-October/118428.html
[2] https://bugs.llvm.org/show_bug.cgi?id=34533

Differential Revision: https://reviews.llvm.org/D69471

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A fix of the bug introduced by previous lowering in asm patch.

Differential Revision: https://reviews.llvm.org/D70243

[AIX][XCOFF] Add support for generating assembly code for one-byte mergable strings

This patch adds support for generating assembly code for one-byte mergeable strings.

Generating assembly code for

[AIX][XCOFF] Add support for generating assembly code for one-byte mergable strings

This patch adds support for generating assembly code for one-byte mergeable strings.

Generating assembly code for multi-byte mergeable strings and the `XCOFF` object code for mergeable strings will be supported later.

Reviewers: hubert.reinterpretcast, jasonliu, daltenty, sfertile, DiggerLin, Xiangling_L

Reviewed by: daltenty

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D70310

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[AIX] Lowering jump table, constant pool and block address in asm

This patch lowering jump table, constant pool and block address in assembly.
1. On AIX, jump table index is always relative;
2. Put

[AIX] Lowering jump table, constant pool and block address in asm

This patch lowering jump table, constant pool and block address in assembly.
1. On AIX, jump table index is always relative;
2. Put CPI and JTI into ReadOnlySection until we support unique data sections;
3. Create the temp symbol for block address symbol;
4. Update MIR testcases and add related assembly part;

Differential Revision: https://reviews.llvm.org/D70243

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Add read-only data assembly writing for aix

SUMMARY:
The patch will emit read-only variable assembly code for aix.

Reviewers: daltenty,Xiangling_Liao
Subscribers: rupprecht, seiyai,hiraditya

Diffe

Add read-only data assembly writing for aix

SUMMARY:
The patch will emit read-only variable assembly code for aix.

Reviewers: daltenty,Xiangling_Liao
Subscribers: rupprecht, seiyai,hiraditya

Differential Revision: https://reviews.llvm.org/D70182

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[PowerPC][XCOFF] Add support for zero initialized global values.

For XCOFF, globals mapped into the .bss section are linked as COMMON
definitions. This behaviour is incorrect for zero initialized da

[PowerPC][XCOFF] Add support for zero initialized global values.

For XCOFF, globals mapped into the .bss section are linked as COMMON
definitions. This behaviour is incorrect for zero initialized data, so
emit those to the .data section instead.

Differential Revision: https://reviews.llvm.org/D69528

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Added support for "#pragma clang section relro=<name>"

Differential Revision: https://reviews.llvm.org/D68806

llvm-svn: 374934

[Alignment][NFC] DataLayout migration to llvm::Align

Summary:
This is patch is part of a series to introduce an Alignment type.
See this thread for context: http://lists.llvm.org/pipermail/llvm-dev/

[Alignment][NFC] DataLayout migration to llvm::Align

Summary:
This is patch is part of a series to introduce an Alignment type.
See this thread for context: http://lists.llvm.org/pipermail/llvm-dev/2019-July/133851.html
See this patch for the introduction of the type: https://reviews.llvm.org/D64790

Reviewers: courbet

Subscribers: jholewinski, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D67914

llvm-svn: 372596

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AArch64: support arm64_32, an ILP32 slice for watchOS.

This is the main CodeGen patch to support the arm64_32 watchOS ABI in LLVM.
FastISel is mostly disabled for now since it would generate incorre

AArch64: support arm64_32, an ILP32 slice for watchOS.

This is the main CodeGen patch to support the arm64_32 watchOS ABI in LLVM.
FastISel is mostly disabled for now since it would generate incorrect code for
ILP32.

llvm-svn: 371722

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[PowerPC][AIX] Adds support for writing the .data section in assembly files

Summary:
Adds support for generating the .data section in assembly files for global variables with a non-zero initializati

[PowerPC][AIX] Adds support for writing the .data section in assembly files

Summary:
Adds support for generating the .data section in assembly files for global variables with a non-zero initialization. The support for writing the .data section in XCOFF object files will be added in a follow-on patch. Any relocations are not included in this patch.

Reviewers: hubert.reinterpretcast, sfertile, jasonliu, daltenty, Xiangling_L

Reviewed by: hubert.reinterpretcast

Subscribers: nemanjai, hiraditya, kbarton, MaskRay, jsji, wuzish, shchenz, DiggerLin, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D66154

llvm-svn: 369869

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[MachO][TLOF] Use hasLocalLinkage to determine if indirect symbol is local

Local symbols in the indirect symbol table contain the value
`INDIRECT_SYMBOL_LOCAL` and the corresponding __pointers entry

[MachO][TLOF] Use hasLocalLinkage to determine if indirect symbol is local

Local symbols in the indirect symbol table contain the value
`INDIRECT_SYMBOL_LOCAL` and the corresponding __pointers entry must
contain the address of the target.

In r349060, I added support for local symbols in the indirect symbol
table, which was checking if the symbol `isDefined` && `!isExternal` to
determine if the symbol is local or not.

It turns out that `isDefined` will return false if the user of the
symbol comes before its definition, and we'll again generate .long 0
which will be the symbol at the adress 0x0.

Instead of doing that, use GlobalValue::hasLocalLinkage() to check if
the symbol is local.

Differential Revision: https://reviews.llvm.org/D66563

llvm-svn: 369671

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[COFF] Fix section name for constants larger than 64 bits on Windows

APIntToHexString returns wrong value ("0000000000000000ffffffffffffffff")
for integer larger than 64 bits, and thus
TargetLowerin

[COFF] Fix section name for constants larger than 64 bits on Windows

APIntToHexString returns wrong value ("0000000000000000ffffffffffffffff")
for integer larger than 64 bits, and thus
TargetLoweringObjectFileCOFF::getSectionForConstant returns same section name
for all numbers larger than 64 bits. This patch tries to fix it.

Differential Revision: https://reviews.llvm.org/D66458
Patch by Senran Zhang

llvm-svn: 369610

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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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Fixed placement of llvm.global_dtors on Windows.

Differential revision: https://reviews.llvm.org/D66373

llvm-svn: 369299

Enable assembly output of local commons for AIX

Summary:
This patch enable assembly output of local commons for AIX using .lcomm
directives. Adds a EmitXCOFFLocalCommonSymbol to MCStreamer so we can

Enable assembly output of local commons for AIX

Summary:
This patch enable assembly output of local commons for AIX using .lcomm
directives. Adds a EmitXCOFFLocalCommonSymbol to MCStreamer so we can emit the
AIX version of .lcomm assembly directives which include a csect name. Handle the
case of BSS locals in PPCAIXAsmPrinter by using EmitXCOFFLocalCommonSymbol. Adds
a test for generating .lcomm on AIX Targets.

Reviewers: cebowleratibm, hubert.reinterpretcast, Xiangling_L, jasonliu, sfertile

Reviewed By: sfertile

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D64825

llvm-svn: 368306

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Revert r367501 "Create unique, but identically-named ELF sections..."

This reverts commit fbc563e2cb6c5f1d0200b390513506b6aca4d2e9 "Create
unique, but identically-named ELF sections for explicitly-s

Revert r367501 "Create unique, but identically-named ELF sections..."

This reverts commit fbc563e2cb6c5f1d0200b390513506b6aca4d2e9 "Create
unique, but identically-named ELF sections for explicitly-sectioned
functions and globals when using -function-sections and
-data-sections."

Reason for revert: sections are created with potentially wrong
attributes.

llvm-svn: 368204

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Create unique, but identically-named ELF sections for explicitly-sectioned functions and globals when using -function-sections and -data-sections.

This allows functions and globals to to be reordere

Create unique, but identically-named ELF sections for explicitly-sectioned functions and globals when using -function-sections and -data-sections.

This allows functions and globals to to be reordered later in the linking phase
(using the -symbol-ordering-file) even though reordering will be limited to
the scope of the explicit section.

Patch by Rahman Lavaee!

Differential Revision: https://reviews.llvm.org/D65478

llvm-svn: 367501

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Address post commit review comments on revision 366727.

Addresses number of comment made on D64652 after commiting:

- Reorders function decls in the TargetLoweringObjectFileXCOFF class.
- Fix comme

Address post commit review comments on revision 366727.

Addresses number of comment made on D64652 after commiting:

- Reorders function decls in the TargetLoweringObjectFileXCOFF class.
- Fix comment in MCSectionXCOFF to include description of external reference
csects.
- Convert several llvm_unreachables to report_fatal_error
- Convert several dyn_casts to casts as they are expected not to fail.
- Avoid copying DataLayout object.

llvm-svn: 367324

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[PowerPC][AIX]Add lowering of MCSymbol MachineOperand.

Adds machine operand lowering for MCSymbolSDNodes to the PowerPC
backend. This is needed to produce call instructions in assembly for AIX
becau

[PowerPC][AIX]Add lowering of MCSymbol MachineOperand.

Adds machine operand lowering for MCSymbolSDNodes to the PowerPC
backend. This is needed to produce call instructions in assembly for AIX
because the callee operand is a MCSymbolSDNode. The test is XFAIL'ed for
asserts due to a (valid) assertion in PEI that the AIX ABI isn't supported yet.

Differential Revision: https://reviews.llvm.org/D63738

llvm-svn: 367133

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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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CodeGen: Allow !associated metadata to point to aliases.

This is a small extension of !associated, mostly useful for the implementation
convenience of instrumentation passes that RAUW globals with a

CodeGen: Allow !associated metadata to point to aliases.

This is a small extension of !associated, mostly useful for the implementation
convenience of instrumentation passes that RAUW globals with aliases, such
as LowerTypeTests.

Differential Revision: https://reviews.llvm.org/D64951

llvm-svn: 366502

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[AsmPrinter] Make the encoding of call sites in .gcc_except_table configurable and use for RISC-V

The original behavior was to always emit the offsets to each call site in the
call site table as ule

[AsmPrinter] Make the encoding of call sites in .gcc_except_table configurable and use for RISC-V

The original behavior was to always emit the offsets to each call site in the
call site table as uleb128 values, however on some architectures (eg RISCV)
these uleb128 offsets into the code cannot always be resolved until link time
(because relaxation will invalidate any calculated offsets), and there are no
appropriate relocations for uleb128 values. As a consequence it needs to be
possible to specify an alternative.

This also switches RISCV to use DW_EH_PE_udata4 for call side encodings in
.gcc_except_table

Differential Revision: https://reviews.llvm.org/D63415
Patch by Edward Jones.

llvm-svn: 366329

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[RISCV] Set correct encodings for DWARF exception handling

This patch sets correct encodings for DWARF exception handling for RISC-V
(other than call site encoding, which must be udata4 rather than

[RISCV] Set correct encodings for DWARF exception handling

This patch sets correct encodings for DWARF exception handling for RISC-V
(other than call site encoding, which must be udata4 rather than uleb128 and
is handled by D63415).

This has the same intend as D63409, except this version matches GCC/binutils
behaviour which uses the same encodings regardless of PIC/non-PIC and
medlow/medany code model.

llvm-svn: 366327

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Standardize on MSVC behavior for triples with no environment

Summary:
This makes it so that IR files using triples without an environment work
out of the box, without normalizing them.

Typically, t

Standardize on MSVC behavior for triples with no environment

Summary:
This makes it so that IR files using triples without an environment work
out of the box, without normalizing them.

Typically, the MSVC behavior is more desirable. For example, it tends to
enable things like constant merging, use of associative comdats, etc.

Addresses PR42491

Reviewers: compnerd

Subscribers: hiraditya, dexonsmith, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D64109

llvm-svn: 365387

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[ELF] Implement Dependent Libraries Feature

This patch implements a limited form of autolinking primarily designed to allow
either the --dependent-library compiler option, or "comment lib" pragmas (

[ELF] Implement Dependent Libraries Feature

This patch implements a limited form of autolinking primarily designed to allow
either the --dependent-library compiler option, or "comment lib" pragmas (
https://docs.microsoft.com/en-us/cpp/preprocessor/comment-c-cpp?view=vs-2017) in
C/C++ e.g. #pragma comment(lib, "foo"), to cause an ELF linker to automatically
add the specified library to the link when processing the input file generated
by the compiler.

Currently this extension is unique to LLVM and LLD. However, care has been taken
to design this feature so that it could be supported by other ELF linkers.

The design goals were to provide:

- A simple linking model for developers to reason about.
- The ability to to override autolinking from the linker command line.
- Source code compatibility, where possible, with "comment lib" pragmas in other
environments (MSVC in particular).

Dependent library support is implemented differently for ELF platforms than on
the other platforms. Primarily this difference is that on ELF we pass the
dependent library specifiers directly to the linker without manipulating them.
This is in contrast to other platforms where they are mapped to a specific
linker option by the compiler. This difference is a result of the greater
variety of ELF linkers and the fact that ELF linkers tend to handle libraries in
a more complicated fashion than on other platforms. This forces us to defer
handling the specifiers to the linker.

In order to achieve a level of source code compatibility with other platforms
we have restricted this feature to work with libraries that meet the following
"reasonable" requirements:

1. There are no competing defined symbols in a given set of libraries, or
if they exist, the program owner doesn't care which is linked to their
program.
2. There may be circular dependencies between libraries.

The binary representation is a mergeable string section (SHF_MERGE,
SHF_STRINGS), called .deplibs, with custom type SHT_LLVM_DEPENDENT_LIBRARIES
(0x6fff4c04). The compiler forms this section by concatenating the arguments of
the "comment lib" pragmas and --dependent-library options in the order they are
encountered. Partial (-r, -Ur) links are handled by concatenating .deplibs
sections with the normal mergeable string section rules. As an example, #pragma
comment(lib, "foo") would result in:

.section ".deplibs","MS",@llvm_dependent_libraries,1
.asciz "foo"

For LTO, equivalent information to the contents of a the .deplibs section can be
retrieved by the LLD for bitcode input files.

LLD processes the dependent library specifiers in the following way:

1. Dependent libraries which are found from the specifiers in .deplibs sections
of relocatable object files are added when the linker decides to include that
file (which could itself be in a library) in the link. Dependent libraries
behave as if they were appended to the command line after all other options. As
a consequence the set of dependent libraries are searched last to resolve
symbols.
2. It is an error if a file cannot be found for a given specifier.
3. Any command line options in effect at the end of the command line parsing apply
to the dependent libraries, e.g. --whole-archive.
4. The linker tries to add a library or relocatable object file from each of the
strings in a .deplibs section by; first, handling the string as if it was
specified on the command line; second, by looking for the string in each of the
library search paths in turn; third, by looking for a lib<string>.a or
lib<string>.so (depending on the current mode of the linker) in each of the
library search paths.
5. A new command line option --no-dependent-libraries tells LLD to ignore the
dependent libraries.

Rationale for the above points:

1. Adding the dependent libraries last makes the process simple to understand
from a developers perspective. All linkers are able to implement this scheme.
2. Error-ing for libraries that are not found seems like better behavior than
failing the link during symbol resolution.
3. It seems useful for the user to be able to apply command line options which
will affect all of the dependent libraries. There is a potential problem of
surprise for developers, who might not realize that these options would apply
to these "invisible" input files; however, despite the potential for surprise,
this is easy for developers to reason about and gives developers the control
that they may require.
4. This algorithm takes into account all of the different ways that ELF linkers
find input files. The different search methods are tried by the linker in most
obvious to least obvious order.
5. I considered adding finer grained control over which dependent libraries were
ignored (e.g. MSVC has /nodefaultlib:<library>); however, I concluded that this
is not necessary: if finer control is required developers can fall back to using
the command line directly.

RFC thread: http://lists.llvm.org/pipermail/llvm-dev/2019-March/131004.html.

Differential Revision: https://reviews.llvm.org/D60274

llvm-svn: 360984

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