reland [IR] make -stack-alignment= into a module attr

Relands commit 433c8d950cb3a1fa0977355ce0367e8c763a3f13 with fixes for
MIPS.

Similar to D102742, specifying the stack alignment via CodegenOpts

reland [IR] make -stack-alignment= into a module attr

Relands commit 433c8d950cb3a1fa0977355ce0367e8c763a3f13 with fixes for
MIPS.

Similar to D102742, specifying the stack alignment via CodegenOpts means
that this flag gets dropped during LTO, unless the command line is
re-specified as a plugin opt. Instead, encode this information as a
module level attribute so that we don't have to expose this llvm
internal flag when linking the Linux kernel with LTO.

Looks like external dependencies might need a fix:
* https://github.com/llvm-hs/llvm-hs/issues/345
* https://github.com/halide/Halide/issues/6079

Link: https://github.com/ClangBuiltLinux/linux/issues/1377

Reviewed By: tejohnson

Differential Revision: https://reviews.llvm.org/D103048

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Revert "[IR] make -stack-alignment= into a module attr"

This reverts commit 433c8d950cb3a1fa0977355ce0367e8c763a3f13.

Breaks the MIPS build.

[IR] make -stack-alignment= into a module attr

Similar to D102742, specifying the stack alignment via CodegenOpts means
that this flag gets dropped during LTO, unless the command line is
re-specifie

[IR] make -stack-alignment= into a module attr

Similar to D102742, specifying the stack alignment via CodegenOpts means
that this flag gets dropped during LTO, unless the command line is
re-specified as a plugin opt. Instead, encode this information as a
module level attribute so that we don't have to expose this llvm
internal flag when linking the Linux kernel with LTO.

Looks like external dependencies might need a fix:
* https://github.com/llvm-hs/llvm-hs/issues/345
* https://github.com/halide/Halide/issues/6079

Link: https://github.com/ClangBuiltLinux/linux/issues/1377

Reviewed By: tejohnson

Differential Revision: https://reviews.llvm.org/D103048

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[IR] make stack-protector-guard-* flags into module attrs

D88631 added initial support for:

- -mstack-protector-guard=
- -mstack-protector-guard-reg=
- -mstack-protector-guard-offset=

flags, and D

[IR] make stack-protector-guard-* flags into module attrs

D88631 added initial support for:

- -mstack-protector-guard=
- -mstack-protector-guard-reg=
- -mstack-protector-guard-offset=

flags, and D100919 extended these to AArch64. Unfortunately, these flags
aren't retained for LTO. Make them module attributes rather than
TargetOptions.

Link: https://github.com/ClangBuiltLinux/linux/issues/1378

Reviewed By: tejohnson

Differential Revision: https://reviews.llvm.org/D102742

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[AArch64] Support customizing stack protector guard

Follow up to D88631 but for aarch64; the Linux kernel uses the command
line flags:

1. -mstack-protector-guard=sysreg
2. -mstack-protector-guard-r

[AArch64] Support customizing stack protector guard

Follow up to D88631 but for aarch64; the Linux kernel uses the command
line flags:

1. -mstack-protector-guard=sysreg
2. -mstack-protector-guard-reg=sp_el0
3. -mstack-protector-guard-offset=0

to use the system register sp_el0 for the stack canary, enabling the
kernel to have a unique stack canary per task (like a thread, but not
limited to userspace as the kernel can preempt itself).

Address pr/47341 for aarch64.

Fixes: https://github.com/ClangBuiltLinux/linux/issues/289
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>

Reviewed By: xiangzhangllvm, DavidSpickett, dmgreen

Differential Revision: https://reviews.llvm.org/D100919

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[Debug-Info] add -gstrict-dwarf support in backend

Reviewed By: dblaikie, probinson

Differential Revision: https://reviews.llvm.org/D100826

[CodeGenOptions] make StackProtectorGuardOffset signed

GCC supports negative values for -mstack-protector-guard-offset=, this
should be a signed value. Pre-req to D100919.

Reviewed By: MaskRay

Dif

[CodeGenOptions] make StackProtectorGuardOffset signed

GCC supports negative values for -mstack-protector-guard-offset=, this
should be a signed value. Pre-req to D100919.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D101325

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[IR][sanitizer] Add module flag "frame-pointer" and set it for cc1 -mframe-pointer={non-leaf,all}

The Linux kernel objtool diagnostic `call without frame pointer save/setup`
arise in multiple instru

[IR][sanitizer] Add module flag "frame-pointer" and set it for cc1 -mframe-pointer={non-leaf,all}

The Linux kernel objtool diagnostic `call without frame pointer save/setup`
arise in multiple instrumentation passes (asan/tsan/gcov). With the mechanism
introduced in D100251, it's trivial to respect the command line
-m[no-]omit-leaf-frame-pointer/-f[no-]omit-frame-pointer, so let's do it.

Fix: https://github.com/ClangBuiltLinux/linux/issues/1236 (tsan)
Fix: https://github.com/ClangBuiltLinux/linux/issues/1238 (asan)

Also document the function attribute "frame-pointer" which is long overdue.

Differential Revision: https://reviews.llvm.org/D101016

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[Support] Don't include VirtualFileSystem.h in CommandLine.h

CommandLine.h is indirectly included in ~50% of TUs when building
clang, and VirtualFileSystem.h is large.

(Already remarked by jhenders

[Support] Don't include VirtualFileSystem.h in CommandLine.h

CommandLine.h is indirectly included in ~50% of TUs when building
clang, and VirtualFileSystem.h is large.

(Already remarked by jhenderson on D70769.)

No behavior change.

Differential Revision: https://reviews.llvm.org/D100957

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[Debug-Info] Use inlined strings in .dwinfo section by default for DBX.

Summary: Set the default DwarfInlinedStrings as inlined strings for DBX, due to DBX does not support .dwstr section for now.

[Debug-Info] Use inlined strings in .dwinfo section by default for DBX.

Summary: Set the default DwarfInlinedStrings as inlined strings for DBX, due to DBX does not support .dwstr section for now.

Reviewed By: dblaikie

Differential Revision: https://reviews.llvm.org/D99933

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[AIX][XCOFF] emit traceback table for function in aix

SUMMARY:
1. added a new option -xcoff-traceback-table to control whether generate traceback table for function.
2. implement the functionality

[AIX][XCOFF] emit traceback table for function in aix

SUMMARY:
1. added a new option -xcoff-traceback-table to control whether generate traceback table for function.
2. implement the functionality of emit traceback table of a function.

Reviewers: hubert.reinterpretcast, Jason Liu
Differential Revision: https://reviews.llvm.org/D92398

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[CSSPGO] Pseudo probes for function calls.

An indirect call site needs to be probed for its potential call targets. With CSSPGO a direct call also needs a probe so that a calling context can be repr

[CSSPGO] Pseudo probes for function calls.

An indirect call site needs to be probed for its potential call targets. With CSSPGO a direct call also needs a probe so that a calling context can be represented by a stack of callsite probes. Unlike pseudo probes for basic blocks that are in form of standalone intrinsic call instructions, pseudo probes for callsites have to be attached to the call instruction, thus a separate instruction would not work.

One possible way of attaching a probe to a call instruction is to use a special metadata that carries information about the probe. The special metadata will have to make its way through the optimization pipeline down to object emission. This requires additional efforts to maintain the metadata in various places. Given that the `!dbg` metadata is a first-class metadata and has all essential support in place , leveraging the `!dbg` metadata as a channel to encode pseudo probe information is probably the easiest solution.

With the requirement of not inflating `!dbg` metadata that is allocated for almost every instruction, we found that the 32-bit DWARF discriminator field which mainly serves AutoFDO can be reused for pseudo probes. DWARF discriminators distinguish identical source locations between instructions and with pseudo probes such support is not required. In this change we are using the discriminator field to encode the ID and type of a callsite probe and the encoded value will be unpacked and consumed right before object emission. When a callsite is inlined, the callsite discriminator field will go with the inlined instructions. The `!dbg` metadata of an inlined instruction is in form of a scope stack. The top of the stack is the instruction's original `!dbg` metadata and the bottom of the stack is for the original callsite of the top-level inliner. Except for the top of the stack, all other elements of the stack actually refer to the nested inlined callsites whose discriminator field (which actually represents a calliste probe) can be used together to represent the inline context of an inlined PseudoProbeInst or CallInst.

To avoid collision with the baseline AutoFDO in various places that handles dwarf discriminators where a check against the `-pseudo-probe-for-profiling` switch is not available, a special encoding scheme is used to tell apart a pseudo probe discriminator from a regular discriminator. For the regular discriminator, if all lowest 3 bits are non-zero, it means the discriminator is basically empty and all higher 29 bits can be reversed for pseudo probe use.

Callsite pseudo probes are inserted in `SampleProfileProbePass` and a target-independent MIR pass `PseudoProbeInserter` is added to unpack the probe ID/type from `!dbg`.

Note that with this work the switch -debug-info-for-profiling will not work with -pseudo-probe-for-profiling anymore. They cannot be used at the same time.

Reviewed By: wmi

Differential Revision: https://reviews.llvm.org/D91756

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[AIX] Add mabi=vec-extabi options to enable the AIX extended and default vector ABIs.

Added support for the options mabi=vec-extabi and mabi=vec-default which are analogous to qvecnvol and qnovecnvo

[AIX] Add mabi=vec-extabi options to enable the AIX extended and default vector ABIs.

Added support for the options mabi=vec-extabi and mabi=vec-default which are analogous to qvecnvol and qnovecnvol when using XL on AIX.
The extended Altivec ABI on AIX is enabled using mabi=vec-extabi in clang and vec-extabi in llc.

Reviewed By: Xiangling_L, DiggerLin

Differential Revision: https://reviews.llvm.org/D89684

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[X86] Support customizing stack protector guard

Reviewed By: nickdesaulniers, MaskRay

Differential Revision: https://reviews.llvm.org/D88631

[AIX] Turn -fdata-sections on by default in Clang

Summary:

This patch does the following:
1. Make InitTargetOptionsFromCodeGenFlags() accepts Triple as a
parameter, because some options' default v

[AIX] Turn -fdata-sections on by default in Clang

Summary:

This patch does the following:
1. Make InitTargetOptionsFromCodeGenFlags() accepts Triple as a
parameter, because some options' default value is triple dependant.
2. DataSections is turned on by default on AIX for llc.
3. Test cases change accordingly because of the default behaviour change.
4. Clang Driver passes in -fdata-sections by default on AIX.

Reviewed By: MaskRay, DiggerLin

Differential Revision: https://reviews.llvm.org/D88737

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[AIX] add new option -mignore-xcoff-visibility

SUMMARY:

In IBM compiler xlclang , there is an option -fnovisibility which suppresses visibility. For more details see: https://www.ibm.com/support/kn

[AIX] add new option -mignore-xcoff-visibility

SUMMARY:

In IBM compiler xlclang , there is an option -fnovisibility which suppresses visibility. For more details see: https://www.ibm.com/support/knowledgecenter/SSGH3R_16.1.0/com.ibm.xlcpp161.aix.doc/compiler_ref/opt_visibility.html.

We need to add the option -mignore-xcoff-visibility for compatibility with the IBM AIX OS (as the option is enabled by default in AIX). With this option llvm does not emit any visibility attribute to ASM or XCOFF object file.

The option only work on the AIX OS, for other non-AIX OS using the option will report an unsupported options error.

In AIX OS:

1.1 the option -mignore-xcoff-visibility is enabled by default , if there is not -fvisibility=* and -mignore-xcoff-visibility explicitly in the clang command .

1.2 if there is -fvisibility=* explicitly but not -mignore-xcoff-visibility explicitly in the clang command. it will generate visibility attributes.

1.3 if there are both -fvisibility=* and -mignore-xcoff-visibility explicitly in the clang command. The option "-mignore-xcoff-visibility" wins , it do not emit the visibility attribute.

The option -mignore-xcoff-visibility has no effect on visibility attribute when compile with -emit-llvm option to generated LLVM IR.

Reviewer: daltenty,Jason Liu

Differential Revision: https://reviews.llvm.org/D87451

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[llvm][CodeGen] Machine Function Splitter

We introduce a codegen optimization pass which splits functions into hot and cold
parts. This pass leverages the basic block sections feature recently
intro

[llvm][CodeGen] Machine Function Splitter

We introduce a codegen optimization pass which splits functions into hot and cold
parts. This pass leverages the basic block sections feature recently
introduced in LLVM from the Propeller project. The pass targets
functions with profile coverage, identifies cold blocks and moves them
to a separate section. The linker groups all cold blocks across
functions together, decreasing fragmentation and improving icache and
itlb utilization.

We evaluated the Machine Function Splitter pass on clang bootstrap and
SPECInt 2017.

For clang bootstrap we observe a mean 2.33% runtime improvement with a
~32% reduction in itlb and stlb misses. Additionally, L1 icache misses
reduced by 9.5% while L2 instruction misses reduced by 20%.

For SPECInt we report the change in IntRate the C/C++
benchmarks. All benchmarks apart from mcf and x264 improve, on average
by 0.6% with the max for deepsjeng at 1.6%.

Benchmark % Change
500.perlbench_r 0.78
502.gcc_r 0.82
505.mcf_r -0.30
520.omnetpp_r 0.18
523.xalancbmk_r 0.37
525.x264_r -0.46
531.deepsjeng_r 1.61
541.leela_r 0.83
557.xz_r 0.15

Differential Revision: https://reviews.llvm.org/D85368

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[LiveDebugValues] Add switches for using instr-ref variable locations

This patch adds the -Xclang option
"-fexperimental-debug-variable-locations" and same LLVM CodeGen option,
to pick which variabl

[LiveDebugValues] Add switches for using instr-ref variable locations

This patch adds the -Xclang option
"-fexperimental-debug-variable-locations" and same LLVM CodeGen option,
to pick which variable location tracking solution to use.

Right now all the switch does is pick which LiveDebugValues
implementation to use, the normal VarLoc one or the instruction
referencing one in rGae6f78824031. Over time, the aim is to add fragments
of support in aid of the value-tracking RFC:

http://lists.llvm.org/pipermail/llvm-dev/2020-February/139440.html

also controlled by this command line switch. That will slowly move
variable locations to be defined by an instruction calculating a value,
and a DBG_INSTR_REF instruction referring to that value. Thus, this is
going to grow into a "use the new kind of variable locations" switch,
rather than just "use the new LiveDebugValues implementation".

Differential Revision: https://reviews.llvm.org/D83048

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Rename basic block sections options to be consistent.

D68049 created options for basic block sections: -fbasic-block-sections=,
-funique-basic-block-section-names. Rename options in llc and lld (--l

Rename basic block sections options to be consistent.

D68049 created options for basic block sections: -fbasic-block-sections=,
-funique-basic-block-section-names. Rename options in llc and lld (--lto-)
to be consistent. Specifically,

+ Rename basicblock-sections to basic-block-sections
+ Rename unique-bb-section-names to unique-basic-block-section-names

Differential Revision: https://reviews.llvm.org/D84462

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[xray] Option to omit the function index

Summary:
Add a flag to omit the xray_fn_idx to cut size overhead and relocations
roughly in half at the cost of reduced performance for single function
patch

[xray] Option to omit the function index

Summary:
Add a flag to omit the xray_fn_idx to cut size overhead and relocations
roughly in half at the cost of reduced performance for single function
patching. Minor additions to compiler-rt support per-function patching
without the index.

Reviewers: dberris, MaskRay, johnislarry

Subscribers: hiraditya, arphaman, cfe-commits, #sanitizers, llvm-commits

Tags: #clang, #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D81995

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Options for Basic Block Sections, enabled in D68063 and D73674.

This patch adds clang options:
-fbasic-block-sections={all,<filename>,labels,none} and
-funique-basic-block-section-names.
LLVM Suppor

Options for Basic Block Sections, enabled in D68063 and D73674.

This patch adds clang options:
-fbasic-block-sections={all,<filename>,labels,none} and
-funique-basic-block-section-names.
LLVM Support for basic block sections is already enabled.

+ -fbasic-block-sections={all, <file>, labels, none} : Enables/Disables basic
block sections for all or a subset of basic blocks. "labels" only enables
basic block symbols.
+ -funique-basic-block-section-names: Enables unique section names for
basic block sections, disabled by default.

Differential Revision: https://reviews.llvm.org/D68049

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CommandFlags.h - remove unnecessary includes. NFC.

Replace with forward declarations and move necessary includes down to source files.

Exposes an implicit dependency on TargetMachine.h in llvm-opt-

CommandFlags.h - remove unnecessary includes. NFC.

Replace with forward declarations and move necessary includes down to source files.

Exposes an implicit dependency on TargetMachine.h in llvm-opt-fuzzer.cpp

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CodeGen: Add -denormal-fp-math-f32 flag

Make the set of FP related attributes and command flags closer.

Fix denormal-fp-math flag and attribute interaction

Make these behave the same way unsafe-fp-math and co. The command line
flag should add the attribute to functions that do not already have
it, and

Fix denormal-fp-math flag and attribute interaction

Make these behave the same way unsafe-fp-math and co. The command line
flag should add the attribute to functions that do not already have
it, and leave existing attributes. The attribute is the actual
implementation, but the flag is useful in some testing situations.

AMDGPU has a variety of tests with denormals enabled/disabled that
would require a painful level of test duplication without a flag. This
doesn't expose setting the separate input/output modes, or add a flag
for the f32 version yet.

Tests will be included in future patch.

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Reland D73534: [DebugInfo] Enable the debug entry values feature by default

The issue that was causing the build failures was fixed with the D76164.