1698 Commits

Author SHA1 Message Date
Fangrui Song
2786e673c7 [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
2021-04-22 18:07:30 -07:00
Fangrui Song
775a9483e5 [IR][sanitizer] Set nounwind on module ctor/dtor, additionally set uwtable if -fasynchronous-unwind-tables
On ELF targets, if a function has uwtable or personality, or does not have
nounwind (`needsUnwindTableEntry`), it marks that `.eh_frame` is needed in the module.

Then, a function gets `.eh_frame` if `needsUnwindTableEntry` or `-g[123]` is specified.
(i.e. If -g[123], every function gets `.eh_frame`.
This behavior is strange but that is the status quo on GCC and Clang.)

Let's take asan as an example. Other sanitizers are similar.
`asan.module_[cd]tor` has no attribute. `needsUnwindTableEntry` returns true,
so every function gets `.eh_frame` if `-g[123]` is specified.
This is the root cause that
`-fno-exceptions -fno-asynchronous-unwind-tables -g` produces .debug_frame
while
`-fno-exceptions -fno-asynchronous-unwind-tables -g -fsanitize=address` produces .eh_frame.

This patch

* sets the nounwind attribute on sanitizer module ctor/dtor.
* let Clang emit a module flag metadata "uwtable" for -fasynchronous-unwind-tables. If "uwtable" is set, sanitizer module ctor/dtor additionally get the uwtable attribute.

The "uwtable" mechanism is generic: synthesized functions not cloned/specialized
from existing ones should consider `Function::createWithDefaultAttr` instead of
`Function::create` if they want to get some default attributes which
have more of module semantics.

Other candidates: "frame-pointer" (https://github.com/ClangBuiltLinux/linux/issues/955
https://github.com/ClangBuiltLinux/linux/issues/1238), dso_local, etc.

Differential Revision: https://reviews.llvm.org/D100251
2021-04-21 15:58:20 -07:00
Erich Keane
0ed613612c Ensure target-multiversioning emits deferred declarations
As reported in PR50025, sometimes we would end up not emitting functions
needed by inline multiversioned variants. This is because we typically
use the 'deferred decl' mechanism to emit these.  However, the variants
are emitted after that typically happens.  This fixes that by ensuring
we re-run deferred decls after this happens. Also, the multiversion
emission is done recursively to ensure that MV functions that require
other MV functions to be emitted get emitted.
2021-04-20 08:10:26 -07:00
Jan Svoboda
6a72ed239c [clang] NFC: Fix range-based for loop warnings related to decl lookup 2021-04-19 18:31:31 +02:00
Alexey Bataev
f6f21dcd6c [OPENMP]Fix PR49636: Assertion `(!Entry.getAddress() || Entry.getAddress() == Addr) && "Resetting with the new address."' failed.
The original issue is caused by the fact that the variable is allocated
with incorrect type i1 instead of i8. This causes the bitcasting of the
declaration to i8 type and the bitcast expression does not match the
original variable.
To fix the problem, the UndefValue initializer and the original
variable should be emitted with type i8, not i1.

Differential Revision: https://reviews.llvm.org/D99297
2021-03-29 06:55:57 -07:00
Alex Lorenz
d672d5219a Revert "[CodeGenModule] Set dso_local for Mach-O GlobalValue"
This reverts commit 809a1e0ffd7af40ee27270ff8ba2ffc927330e71.

Mach-O doesn't support dso_local and this change broke XNU because of the use of dso_local.

Differential Revision: https://reviews.llvm.org/D98458
2021-03-17 17:27:41 -07:00
Luke Drummond
440f6bdf34 [OpenCL][NFCI] Prefer CodeGenFunction::EmitRuntimeCall
`CodeGenFunction::EmitRuntimeCall` automatically sets the right calling
convention for the callee so we can avoid setting it ourselves.

As requested in https://reviews.llvm.org/D98411

Reviewed by: anastasia
Differential Revision: https://reviews.llvm.org/D98705
2021-03-16 16:22:19 +00:00
Luke Drummond
fcfd3fda71 [OpenCL] Respect calling convention for builtin
`__translate_sampler_initializer` has a calling convention of
`spir_func`, but clang generated calls to it using the default CC.

Instruction Combining was lowering these mismatching calling conventions
to `store i1* undef` which itself was subsequently lowered to a trap
instruction by simplifyCFG resulting in runtime `SIGILL`

There are arguably two bugs here: but whether there's any wisdom in
converting an obviously invalid call into a runtime crash over aborting
with a sensible error message will require further discussion. So for
now it's enough to set the right calling convention on the runtime
helper.

Reviewed By: svenh, bader

Differential Revision: https://reviews.llvm.org/D98411
2021-03-15 17:26:51 +00:00
Sriraman Tallam
cdb42a4cc4 Disable unique linkage suffixes ifor global vars until demanglers can be fixed.
D96109 added support for unique internal linkage names for both internal
linkage functions and global variables. There was a lot of discussion on how to
get the demangling right for functions but I completely missed the point that
demanglers do not support suffixes for global vars. For example:

$ c++filt _ZL3foo
foo
$ c++filt _ZL3foo.uniq.123
_ZL3foo.uniq.123

The demangling for functions works as expected.

I am not sure of the impact of this. I don't understand how debuggers and other
tools depend on the correctness of global variable demangling so I am
pre-emptively disabling it until we can get the demangling support added.

Importantly, uniquefying global variables is not needed right now as we do not
do profile attribution to global vars based on sampling. It was added for
completeness and so this feature is not exactly missed.

Differential Revision: https://reviews.llvm.org/D98392
2021-03-11 20:59:30 -08:00
Sriraman Tallam
78d0e91865 Refactor -funique-internal-linakge-names implementation.
The option -funique-internal-linkage-names was added in D73307 and D78243 as a
LLVM early pass to insert a unique suffix to internal linkage functions and
vars. The unique suffix was the hash of the module path. However, we found
that this can be done more cleanly in clang early and the fixes that need to
be done later can be completely avoided. The fixes in particular are trying
to modify the DW_AT_linkage_name and finding the right place to insert the
pass.

This patch ressurects the original implementation proposed in D73307 which
was reviewed and then ditched in favor of the pass based approach.

Differential Revision: https://reviews.llvm.org/D96109
2021-03-05 13:32:17 -08:00
Akira Hatanaka
1900503595 [ObjC][ARC] Use operand bundle 'clang.arc.attachedcall' instead of
explicitly emitting retainRV or claimRV calls in the IR

This reapplies ed4718eccb12bd42214ca4fb17d196d49561c0c7, which was reverted
because it was causing a miscompile. The bug that was causing the miscompile
has been fixed in 75805dce5ff874676f3559c069fcd6737838f5c0.

Original commit message:

Background:

This fixes a longstanding problem where llvm breaks ARC's autorelease
optimization (see the link below) by separating calls from the marker
instructions or retainRV/claimRV calls. The backend changes are in
https://reviews.llvm.org/D92569.

https://clang.llvm.org/docs/AutomaticReferenceCounting.html#arc-runtime-objc-autoreleasereturnvalue

What this patch does to fix the problem:

- The front-end adds operand bundle "clang.arc.attachedcall" to calls,
  which indicates the call is implicitly followed by a marker
  instruction and an implicit retainRV/claimRV call that consumes the
  call result. In addition, it emits a call to
  @llvm.objc.clang.arc.noop.use, which consumes the call result, to
  prevent the middle-end passes from changing the return type of the
  called function. This is currently done only when the target is arm64
  and the optimization level is higher than -O0.

- ARC optimizer temporarily emits retainRV/claimRV calls after the calls
  with the operand bundle in the IR and removes the inserted calls after
  processing the function.

- ARC contract pass emits retainRV/claimRV calls after the call with the
  operand bundle. It doesn't remove the operand bundle on the call since
  the backend needs it to emit the marker instruction. The retainRV and
  claimRV calls are emitted late in the pipeline to prevent optimization
  passes from transforming the IR in a way that makes it harder for the
  ARC middle-end passes to figure out the def-use relationship between
  the call and the retainRV/claimRV calls (which is the cause of
  PR31925).

- The function inliner removes an autoreleaseRV call in the callee if
  nothing in the callee prevents it from being paired up with the
  retainRV/claimRV call in the caller. It then inserts a release call if
  claimRV is attached to the call since autoreleaseRV+claimRV is
  equivalent to a release. If it cannot find an autoreleaseRV call, it
  tries to transfer the operand bundle to a function call in the callee.
  This is important since the ARC optimizer can remove the autoreleaseRV
  returning the callee result, which makes it impossible to pair it up
  with the retainRV/claimRV call in the caller. If that fails, it simply
  emits a retain call in the IR if retainRV is attached to the call and
  does nothing if claimRV is attached to it.

- SCCP refrains from replacing the return value of a call with a
  constant value if the call has the operand bundle. This ensures the
  call always has at least one user (the call to
  @llvm.objc.clang.arc.noop.use).

- This patch also fixes a bug in replaceUsesOfNonProtoConstant where
  multiple operand bundles of the same kind were being added to a call.

Future work:

- Use the operand bundle on x86-64.

- Fix the auto upgrader to convert call+retainRV/claimRV pairs into
  calls with the operand bundles.

rdar://71443534

Differential Revision: https://reviews.llvm.org/D92808
2021-03-04 11:22:30 -08:00
Wang, Pengfei
e7e67c930a Add Windows ehcont section support (/guard:ehcont).
Add option /guard:ehcont

Reviewed By: rnk

Differential Revision: https://reviews.llvm.org/D96709
2021-03-04 11:47:29 +08:00
Hans Wennborg
0a5dd06718 Revert "[ObjC][ARC] Use operand bundle 'clang.arc.attachedcall' instead of explicitly emitting retainRV or claimRV calls in the IR"
This caused miscompiles of Chromium tests for iOS due clobbering of live
registers. See discussion on the code review for details.

> Background:
>
> This fixes a longstanding problem where llvm breaks ARC's autorelease
> optimization (see the link below) by separating calls from the marker
> instructions or retainRV/claimRV calls. The backend changes are in
> https://reviews.llvm.org/D92569.
>
> https://clang.llvm.org/docs/AutomaticReferenceCounting.html#arc-runtime-objc-autoreleasereturnvalue
>
> What this patch does to fix the problem:
>
> - The front-end adds operand bundle "clang.arc.attachedcall" to calls,
>   which indicates the call is implicitly followed by a marker
>   instruction and an implicit retainRV/claimRV call that consumes the
>   call result. In addition, it emits a call to
>   @llvm.objc.clang.arc.noop.use, which consumes the call result, to
>   prevent the middle-end passes from changing the return type of the
>   called function. This is currently done only when the target is arm64
>   and the optimization level is higher than -O0.
>
> - ARC optimizer temporarily emits retainRV/claimRV calls after the calls
>   with the operand bundle in the IR and removes the inserted calls after
>   processing the function.
>
> - ARC contract pass emits retainRV/claimRV calls after the call with the
>   operand bundle. It doesn't remove the operand bundle on the call since
>   the backend needs it to emit the marker instruction. The retainRV and
>   claimRV calls are emitted late in the pipeline to prevent optimization
>   passes from transforming the IR in a way that makes it harder for the
>   ARC middle-end passes to figure out the def-use relationship between
>   the call and the retainRV/claimRV calls (which is the cause of
>   PR31925).
>
> - The function inliner removes an autoreleaseRV call in the callee if
>   nothing in the callee prevents it from being paired up with the
>   retainRV/claimRV call in the caller. It then inserts a release call if
>   claimRV is attached to the call since autoreleaseRV+claimRV is
>   equivalent to a release. If it cannot find an autoreleaseRV call, it
>   tries to transfer the operand bundle to a function call in the callee.
>   This is important since the ARC optimizer can remove the autoreleaseRV
>   returning the callee result, which makes it impossible to pair it up
>   with the retainRV/claimRV call in the caller. If that fails, it simply
>   emits a retain call in the IR if retainRV is attached to the call and
>   does nothing if claimRV is attached to it.
>
> - SCCP refrains from replacing the return value of a call with a
>   constant value if the call has the operand bundle. This ensures the
>   call always has at least one user (the call to
>   @llvm.objc.clang.arc.noop.use).
>
> - This patch also fixes a bug in replaceUsesOfNonProtoConstant where
>   multiple operand bundles of the same kind were being added to a call.
>
> Future work:
>
> - Use the operand bundle on x86-64.
>
> - Fix the auto upgrader to convert call+retainRV/claimRV pairs into
>   calls with the operand bundles.
>
> rdar://71443534
>
> Differential Revision: https://reviews.llvm.org/D92808

This reverts commit ed4718eccb12bd42214ca4fb17d196d49561c0c7.
2021-03-03 15:51:40 +01:00
Richard Smith
9e2579dbf4 Fix infinite recursion during IR emission if a constant-initialized lifetime-extended temporary object's initializer refers back to the same object.
`GetAddrOfGlobalTemporary` previously tried to emit the initializer of
a global temporary before updating the global temporary map. Emitting the
initializer could recurse back into `GetAddrOfGlobalTemporary` for the same
temporary, resulting in an infinite recursion.

Reviewed By: rjmccall

Differential Revision: https://reviews.llvm.org/D97733
2021-03-01 22:19:21 -08:00
Yaxun (Sam) Liu
5cf2a37f12 [HIP] Emit kernel symbol
Currently clang uses stub function to launch kernel. This is inconvenient
to interop with C++ programs since the stub function has different name
as kernel, which is required by ROCm debugger.

This patch emits a variable symbol which has the same name as the kernel
and uses it to register and launch the kernel. This allows C++ program to
launch a kernel by using the original kernel name.

Reviewed by: Artem Belevich

Differential Revision: https://reviews.llvm.org/D86376
2021-03-01 16:31:40 -05:00
Fangrui Song
8afdacba9d Add GNU attribute 'retain'
For ELF targets, GCC 11 will set SHF_GNU_RETAIN on the section of a
`__attribute__((retain))` function/variable to prevent linker garbage
collection. (See AttrDocs.td for the linker support).

This patch adds `retain` functions/variables to the `llvm.used` list, which has
the desired linker GC semantics. Note: `retain` does not imply `used`,
so an unused function/variable can be dropped by Sema.

Before 'retain' was introduced, previous ELF solutions require inline asm or
linker tricks, e.g.  `asm volatile(".reloc 0, R_X86_64_NONE, target");`
(architecture dependent) or define a non-local symbol in the section and use
`ld -u`. There was no elegant source-level solution.

With D97448, `__attribute__((retain))` will set `SHF_GNU_RETAIN` on ELF targets.

Differential Revision: https://reviews.llvm.org/D97447
2021-02-26 16:37:50 -08:00
Fangrui Song
28cb620321 Change some addUsedGlobal to addUsedOrCompilerUsedGlobal
An global value in the `llvm.used` list does not have GC root semantics on ELF targets.
This will be changed in a subsequent backend patch.

Change some `llvm.used` in the ELF code path to use `llvm.compiler.used` to
prevent undesired GC root semantics.

Change one extern "C" alias (due to `__attribute__((used))` in extern "C") to use `llvm.compiler.used` on all targets.

GNU ld has a rule "`__start_/__stop_` references from a live input section retain the associated C identifier name sections",
which LLD may drop entirely (currently refined to exclude SHF_LINK_ORDER/SHF_GROUP) in a future release (the rule makes it clumsy to GC metadata sections; D96914 added a way to try the potential future behavior).
For `llvm.used` global values defined in a C identifier name section, keep using `llvm.used` so that
the future LLD change will not affect them.

rnk kindly categorized the changes:
```
ObjC/blocks: this wants GC root semantics, since ObjC mainly runs on Mac.
MS C++ ABI stuff: wants GC root semantics, no change
OpenMP: unsure, but GC root semantics probably don't hurt
CodeGenModule: affected in this patch to *not* use GC root semantics so that __attribute__((used)) behavior remains the same on ELF, plus two other minor use cases that don't want GC semantics
Coverage: Probably want GC root semantics
CGExpr.cpp: refers to LTO, wants GC root
CGDeclCXX.cpp: one is MS ABI specific, so yes GC root, one is some other C++ init functionality, which should form GC roots (C++ initializers can have side effects and must run)
CGDecl.cpp: Changed in this patch for __attribute__((used))
```

Differential Revision: https://reviews.llvm.org/D97446
2021-02-26 10:42:07 -08:00
Yaxun (Sam) Liu
47acdec1dd [CUDA][HIP] Support accessing static device variable in host code for -fgpu-rdc
For -fgpu-rdc mode, static device vars in different TU's may have the same name.
To support accessing file-scope static device variables in host code, we need to give them
a distinct name and external linkage. This can be done by postfixing each static device variable with
a distinct CUID (Compilation Unit ID) hash.

Since the static device variables have different name across compilation units, now we let
them have external linkage so that they can be looked up by the runtime.

Reviewed by: Artem Belevich, and Jon Chesterfield

Differential Revision: https://reviews.llvm.org/D85223
2021-02-24 18:23:45 -05:00
Yaxun (Sam) Liu
a3ce7f5cd2 [HIP] Fix managed variable linkage
Currently managed variables are emitted as undefined symbols, which
causes difficulty for diagnosing undefined symbols for non-managed
variables.

This patch transforms managed variables in device compilation so that
they can be emitted as normal variables.

Reviewed by: Artem Belevich

Differential Revision: https://reviews.llvm.org/D96195
2021-02-23 22:34:45 -05:00
Melanie Blower
e64fcdf8d5 [clang][patch] Inclusive language, modify filename SanitizerBlacklist.h to NoSanitizeList.h
This patch responds to a comment from @vitalybuka in D96203: suggestion to
do the change incrementally, and start by modifying this file name. I modified
the file name and made the other changes that follow from that rename.

Reviewers: vitalybuka, echristo, MaskRay, jansvoboda11, aaron.ballman

Differential Revision: https://reviews.llvm.org/D96974
2021-02-22 15:11:37 -05:00
Igor Kudrin
aa84289629 [DebugInfo] Keep the DWARF64 flag in the module metadata
This allows the option to affect the LTO output. Module::Max helps to
generate debug info for all modules in the same format.

Differential Revision: https://reviews.llvm.org/D96597
2021-02-17 17:03:34 +07:00
Artur Gainullin
ff50b121e3 [SYCL] Ignore file-scope asm during device-side SYCL compilation.
Reviewed By: bader, eandrews

Differential Revision: https://reviews.llvm.org/D96538
2021-02-12 17:00:45 -08:00
Akira Hatanaka
ed4718eccb [ObjC][ARC] Use operand bundle 'clang.arc.attachedcall' instead of
explicitly emitting retainRV or claimRV calls in the IR

Background:

This fixes a longstanding problem where llvm breaks ARC's autorelease
optimization (see the link below) by separating calls from the marker
instructions or retainRV/claimRV calls. The backend changes are in
https://reviews.llvm.org/D92569.

https://clang.llvm.org/docs/AutomaticReferenceCounting.html#arc-runtime-objc-autoreleasereturnvalue

What this patch does to fix the problem:

- The front-end adds operand bundle "clang.arc.attachedcall" to calls,
  which indicates the call is implicitly followed by a marker
  instruction and an implicit retainRV/claimRV call that consumes the
  call result. In addition, it emits a call to
  @llvm.objc.clang.arc.noop.use, which consumes the call result, to
  prevent the middle-end passes from changing the return type of the
  called function. This is currently done only when the target is arm64
  and the optimization level is higher than -O0.

- ARC optimizer temporarily emits retainRV/claimRV calls after the calls
  with the operand bundle in the IR and removes the inserted calls after
  processing the function.

- ARC contract pass emits retainRV/claimRV calls after the call with the
  operand bundle. It doesn't remove the operand bundle on the call since
  the backend needs it to emit the marker instruction. The retainRV and
  claimRV calls are emitted late in the pipeline to prevent optimization
  passes from transforming the IR in a way that makes it harder for the
  ARC middle-end passes to figure out the def-use relationship between
  the call and the retainRV/claimRV calls (which is the cause of
  PR31925).

- The function inliner removes an autoreleaseRV call in the callee if
  nothing in the callee prevents it from being paired up with the
  retainRV/claimRV call in the caller. It then inserts a release call if
  claimRV is attached to the call since autoreleaseRV+claimRV is
  equivalent to a release. If it cannot find an autoreleaseRV call, it
  tries to transfer the operand bundle to a function call in the callee.
  This is important since the ARC optimizer can remove the autoreleaseRV
  returning the callee result, which makes it impossible to pair it up
  with the retainRV/claimRV call in the caller. If that fails, it simply
  emits a retain call in the IR if retainRV is attached to the call and
  does nothing if claimRV is attached to it.

- SCCP refrains from replacing the return value of a call with a
  constant value if the call has the operand bundle. This ensures the
  call always has at least one user (the call to
  @llvm.objc.clang.arc.noop.use).

- This patch also fixes a bug in replaceUsesOfNonProtoConstant where
  multiple operand bundles of the same kind were being added to a call.

Future work:

- Use the operand bundle on x86-64.

- Fix the auto upgrader to convert call+retainRV/claimRV pairs into
  calls with the operand bundles.

rdar://71443534

Differential Revision: https://reviews.llvm.org/D92808
2021-02-12 09:51:57 -08:00
Anastasia Stulova
79b222c39f [OpenCL] Fix types with signed prefix in arginfo metadata.
Signed prefix is removed and the single word spelling is
printed for the scalar types.

Tags: #clang

Differential Revision: https://reviews.llvm.org/D96161
2021-02-09 15:13:19 +00:00
Anastasia Stulova
ecc8ac3f08 [OpenCL] Fix pipe type printing in arg info metadata
Pipe element type spelling for arg info metadata
should follow the same behavior as normal type spelling.

We should only use the canonical type spelling in the
base type field.

This patch also removed duplication in type handling.

Tags: #clang

Differential Revision: https://reviews.llvm.org/D96151
2021-02-08 16:05:13 +00:00
Yaxun (Sam) Liu
b008ea304d [CUDA][HIP] Fix device variable linkage
For -fgpu-rdc, shadow variables should not be internalized, otherwise
they cannot be accessed by other TUs. This is necessary because
the shadow variable of external device variables are always
emitted as undefined symbols, which need to resolve to a global
symbols.

Managed variables need to be emitted as undefined symbols
in device compilations.

Reviewed by: Artem Belevich

Differential Revision: https://reviews.llvm.org/D95901
2021-02-05 15:11:12 -05:00
Yaxun (Sam) Liu
0b2af1a288 [NFC][CUDA] Refactor registering device variable
Extract registering device variable to CUDA runtime codegen function since it
will be called in multiple places.

Reviewed by: Artem Belevich

Differential Revision: https://reviews.llvm.org/D95558
2021-02-03 14:29:51 -05:00
Hans Wennborg
0479c53b6c [dllimport] Honor always_inline when deciding whether a dllimport function should be available for inlining (PR48925)
Normally, Clang will not make dllimport functions available for inlining
if they reference non-imported symbols, as this can lead to confusing
link errors. But if the function is marked always_inline, the user
presumably knows what they're doing and the attribute should be honored.

Differential revision: https://reviews.llvm.org/D95673
2021-02-02 10:28:32 +01:00
Petr Hosek
bb9eb19829 Support for instrumenting only selected files or functions
This change implements support for applying profile instrumentation
only to selected files or functions. The implementation uses the
sanitizer special case list format to select which files and functions
to instrument, and relies on the new noprofile IR attribute to exclude
functions from instrumentation.

Differential Revision: https://reviews.llvm.org/D94820
2021-01-26 17:13:34 -08:00
Petr Hosek
1e634f3952 Revert "Support for instrumenting only selected files or functions"
This reverts commit 4edf35f11a9e20bd5df3cb47283715f0ff38b751 because
the test fails on Windows bots.
2021-01-26 12:25:28 -08:00
Petr Hosek
4edf35f11a Support for instrumenting only selected files or functions
This change implements support for applying profile instrumentation
only to selected files or functions. The implementation uses the
sanitizer special case list format to select which files and functions
to instrument, and relies on the new noprofile IR attribute to exclude
functions from instrumentation.

Differential Revision: https://reviews.llvm.org/D94820
2021-01-26 11:11:39 -08:00
Bjorn Pettersson
ea2cfda386 [CGExpr] Use getCharWidth() more consistently in CCGExprConstant. NFC
Most of CGExprConstant.cpp is using the CharUnits abstraction
and is using getCharWidth() (directly of indirectly) when converting
between size of a char and size in bits. This patch is making that
abstraction more consistent by adding CharTy to the CodeGenTypeCache
(honoring getCharWidth() when mapping from char to LLVM IR types,
instead of using Int8Ty directly).

Reviewed By: rjmccall

Differential Revision: https://reviews.llvm.org/D94979
2021-01-22 21:12:17 +01:00
Yaxun (Sam) Liu
622eaa4a4c [HIP] Support __managed__ attribute
This patch implements codegen for __managed__ variable attribute for HIP.

Diagnostics will be added later.

Differential Revision: https://reviews.llvm.org/D94814
2021-01-22 11:43:58 -05:00
Zequan Wu
e53bbd9951 [IR] move nomerge attribute from function declaration/definition to callsites
Move nomerge attribute from function declaration/definition to callsites to
allow virtual function calls attach the attribute.

Differential Revision: https://reviews.llvm.org/D94537
2021-01-12 12:10:46 -08:00
Fangrui Song
e2e82c9983 [CodeGenModule] Drop dso_local on function declarations for ELF -fno-pic -fno-direct-access-external-data
ELF -fno-pic sets dso_local on a function declaration to allow direct accesses
when taking its address (similar to a data symbol). The emitted code follows the
traditional GCC/Clang -fno-pic behavior: an absolute relocation is produced.

If the function is not defined in the executable, a canonical PLT entry will be
needed at link time. This is similar to a copy relocation and is incompatible
with (-Bsymbolic or --dynamic-list linked shared objects / protected symbols in
a shared object).

This patch gives -fno-pic code a way to avoid such a canonical PLT entry.

The FIXME was about a generalization for -fpie -mpie-copy-relocations (now -fpie
-fdirect-access-external-data). While we could set dso_local to avoid GOT when
taking the address of a function declaration (there is an ignorable difference
about R_386_PC32 vs R_386_PLT32 on i386), it likely does not provide any benefit
and can just cause trouble, so we don't make the generalization.
2021-01-09 16:31:56 -08:00
Fangrui Song
38a716c30f Make -fno-pic respect -fno-direct-access-external-data
D92633 added -f[no-]direct-access-external-data to supersede -m[no-]pie-copy-relocations.
(The option works for -fpie but is a no-op for -fno-pic and -fpic.)

This patch makes -fno-pic -fno-direct-access-external-data drop dso_local from
global variable declarations. This usually causes the backend to emit a GOT
indirection for external data access. With a GOT relocation, the subsequent
-no-pie link will not have copy relocation even if the data symbol turns out to
be defined by a shared object.

Differential Revision: https://reviews.llvm.org/D92714
2021-01-09 00:32:02 -08:00
Fangrui Song
1d3ebbf537 Add -f[no-]direct-access-external-data to supersede -mpie-copy-relocations
GCC r218397 "x86-64: Optimize access to globals in PIE with copy reloc" made
-fpie code emit R_X86_64_PC32 to reference external data symbols by default.
Clang adopted -mpie-copy-relocations D19996 as a flexible alternative.

The name -mpie-copy-relocations can be improved [1] and does not capture the
idea that this option can apply to -fno-pic and -fpic [2], so this patch
introduces -f[no-]direct-access-external-data and makes -mpie-copy-relocations
their aliases for compatibility.

[1]
For
```
extern int var;
int get() { return var; }
```
if var is defined in another translation unit in the link unit, there is no copy
relocation.

[2]
-fno-pic -fno-direct-access-external-data is useful to avoid copy relocations.
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65888
If a shared object is linked with -Bsymbolic or --dynamic-list and exports a
data symbol, normally the data symbol cannot be accessed by -fno-pic code
(because by default an absolute relocation is produced which will lead to a copy
relocation). -fno-direct-access-external-data can prevent copy relocations.

-fpic -fdirect-access-external-data can avoid GOT indirection. This is like the
undefined counterpart of -fno-semantic-interposition. However, the user should
define var in another translation unit and link with -Bsymbolic or
--dynamic-list, otherwise the linker will error in a -shared link. Generally
the user has better tools for their goal but I want to mention that this
combination is valid.

On COFF, the behavior is like always -fdirect-access-external-data.
`__declspec(dllimport)` is needed to enable indirect access.

There is currently no plan to affect non-ELF behaviors or -fpic behaviors.

-fno-pic -fno-direct-access-external-data will be implemented in the subsequent patch.

GCC feature request https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98112

Reviewed By: tmsriram

Differential Revision: https://reviews.llvm.org/D92633
2021-01-09 00:32:01 -08:00
Fangrui Song
d1fd72343c Refactor how -fno-semantic-interposition sets dso_local on default visibility external linkage definitions
The idea is that the CC1 default for ELF should set dso_local on default
visibility external linkage definitions in the default -mrelocation-model pic
mode (-fpic/-fPIC) to match COFF/Mach-O and make output IR similar.

The refactoring is made available by 2820a2ca3a0e69c3f301845420e0067ffff2251b.

Currently only x86 supports local aliases. We move the decision to the driver.
There are three CC1 states:

* -fsemantic-interposition: make some linkages interposable and make default visibility external linkage definitions dso_preemptable.
* (default): selected if the target supports .Lfoo$local: make default visibility external linkage definitions dso_local
* -fhalf-no-semantic-interposition: if neither option is set or the target does not support .Lfoo$local: like -fno-semantic-interposition but local aliases are not used. So references can be interposed if not optimized out.

Add -fhalf-no-semantic-interposition to a few tests using the half-based semantic interposition behavior.
2020-12-31 13:59:45 -08:00
Fangrui Song
809a1e0ffd [CodeGenModule] Set dso_local for Mach-O GlobalValue
* static relocation model: always
* other relocation models: if isStrongDefinitionForLinker

This will make LLVM IR emitted for COFF/Mach-O and executable ELF similar.
2020-12-30 20:52:01 -08:00
Fangrui Song
2820a2ca3a Move -fno-semantic-interposition dso_local logic from TargetMachine to Clang CodeGenModule
This simplifies TargetMachine::shouldAssumeDSOLocal and and gives frontend the
decision to use dso_local. For LLVM synthesized functions/globals, they may lose
inferred dso_local but such optimizations are probably not very useful.

Note: the hasComdat() condition in canBenefitFromLocalAlias (D77429) may be dead now.
(llvm/CodeGen/X86/semantic-interposition-comdat.ll)
(Investigate whether we need test coverage when Fuchsia C++ ABI is clearer)
2020-12-29 23:37:55 -08:00
Rong Xu
3733463dbb [IR][PGO] Add hot func attribute and use hot/cold attribute in func section
Clang FE currently has hot/cold function attribute. But we only have
cold function attribute in LLVM IR.

This patch adds support of hot function attribute to LLVM IR.  This
attribute will be used in setting function section prefix/suffix.
Currently .hot and .unlikely suffix only are added in PGO (Sample PGO)
compilation (through isFunctionHotInCallGraph and
isFunctionColdInCallGraph).

This patch changes the behavior. The new behavior is:
(1) If the user annotates a function as hot or isFunctionHotInCallGraph
    is true, this function will be marked as hot. Otherwise,
(2) If the user annotates a function as cold or
    isFunctionColdInCallGraph is true, this function will be marked as
    cold.

The changes are:
(1) user annotated function attribute will used in setting function
    section prefix/suffix.
(2) hot attribute overwrites profile count based hotness.
(3) profile count based hotness overwrite user annotated cold attribute.

The intention for these changes is to provide the user a way to mark
certain function as hot in cases where training input is hard to cover
all the hot functions.

Differential Revision: https://reviews.llvm.org/D92493
2020-12-17 18:41:12 -08:00
Zequan Wu
fb0f728805 [Clang] Make nomerge attribute a function attribute as well as a statement attribute.
Differential Revision: https://reviews.llvm.org/D92800
2020-12-17 07:45:38 -08:00
Rong Xu
c36f31c4db [PGO] remove unintentional code in early commit
Remove unintentional code in
commit 54e03d [PGO] Verify BFI counts after loading profile data.
2020-12-14 18:41:49 -08:00
Rong Xu
54e03d03a7 [PGO] Verify BFI counts after loading profile data
This patch adds the functionality to compare BFI counts with real
profile
counts right after reading the profile. It will print remarks under
-Rpass-analysis=pgo, or the internal option -pass-remarks-analysis=pgo.

Differential Revision: https://reviews.llvm.org/D91813
2020-12-14 15:56:10 -08:00
Fangrui Song
1ab9327d1c [TargetMachine][CodeGenModule] Delete unneeded ppc32 special case from shouldAssumeDSOLocal
PPCMCInstLower does not actually call shouldAssumeDSOLocal for ppc32 so this is dead.
Actually Clang ppc32 does produce a pair of absolute relocations which match GCC.

This also fixes a comment (R_PPC_COPY and R_PPC64_COPY do exist).
2020-12-05 00:42:07 -08:00
Nico Weber
0cbf61be8b [mac/arm] Fix rtti codegen tests when running on an arm mac
shouldRTTIBeUnique() returns false for iOS64CXXABI, which causes
RTTI objects to be emitted hidden. Update two tests that didn't
expect this to happen for the default triple.

Also rename iOS64CXXABI to AppleARM64CXXABI, since it's used for
arm64-apple-macos triples too.

Part of PR46644.

Differential Revision: https://reviews.llvm.org/D91904
2020-12-03 09:11:03 -05:00
Ben Dunbobbin
e42021d5cc [Clang][-fvisibility-from-dllstorageclass] Set DSO Locality from final visibility
Ensure that the DSO Locality of the globals in the IR is derived from
their final visibility when using -fvisibility-from-dllstorageclass.

To accomplish this we reset the DSO locality of globals (before
setting their visibility from their dllstorageclass) at the end of
IRGen in Clang. This removes any effects that visibility options or
annotations may have had on the DSO locality.

The resulting DSO locality of the globals will be pessimistic
w.r.t. to the normal compiler IRGen.

Differential Revision: https://reviews.llvm.org/D91779
2020-11-24 00:32:14 +00:00
Xiangling Liao
17497ec514 [AIX][FE] Support constructor/destructor attribute
Support attribute((constructor)) and attribute((destructor)) on AIX

Differential Revision: https://reviews.llvm.org/D90892
2020-11-19 09:24:01 -05:00
Nick Desaulniers
f4c6080ab8 Revert "[IR] add fn attr for no_stack_protector; prevent inlining on mismatch"
This reverts commit b7926ce6d7a83cdf70c68d82bc3389c04009b841.

Going with a simpler approach.
2020-11-17 17:27:14 -08:00
Richard Smith
b637148ecb [c++20] For P0732R2 / P1907R1: Basic code generation and name
mangling support for non-type template parameters of class type and
template parameter objects.

The Itanium side of this follows the approach I proposed in
https://github.com/itanium-cxx-abi/cxx-abi/issues/47 on 2020-09-06.

The MSVC side of this was determined empirically by observing MSVC's
output.

Differential Revision: https://reviews.llvm.org/D89998
2020-11-09 22:10:27 -08:00