1777 Commits

Author SHA1 Message Date
Yaxun (Sam) Liu
85c2bd2a0e Prevent adding module flag amdgpu_hostcall multiple times
HIP program with printf call fails to compile with -fsanitize=address
option, because of appending module flag - amdgpu_hostcall twice, one
for printf and one for sanitize option. This patch fixes that issue.

Patch by: Praveen Velliengiri

Reviewed by: Yaxun Liu, Roman Lebedev

Differential Revision: https://reviews.llvm.org/D116216
2022-01-19 12:52:33 -05:00
Nikita Popov
c63a3175c2 [AttrBuilder] Remove ctor accepting AttributeList and Index
Use the AttributeSet constructor instead. There's no good reason
why AttrBuilder itself should exact the AttributeSet from the
AttributeList. Moving this out of the AttrBuilder generally results
in cleaner code.
2022-01-15 22:39:31 +01:00
Erich Keane
2bcba21c8b [CPU-Dispatch] Make sure Dispatch names get updated if previously mangled
Cases where there is a mangling of a cpu-dispatch/cpu-specific function
before the function becomes 'multiversion' (such as a member function)
causes the wrong name to be emitted for one of the variants/resolver,
since the name is cached.  Make sure we invalidate the cache in
cpu-dispatch/cpu-specific modes, like we previously did for just target
multiversioning.
2022-01-14 10:45:55 -08:00
Erich Keane
b699e8b11a Add another assert to cpu-dispatch emission to help track down a tough
to repro error.

As mentioned yesterday, I've got a problem that I can only reproduce on
Godbolt (none of the build configs on my local machine!), so this is at
least somewhat usable until I figure out a cause.
2022-01-13 06:54:08 -08:00
Erich Keane
6e77ad11ff Add an assert in cpudispatch emit to try to track down an error.
I'm attempting to debug an issue that I can only get to happen on
godbolt, where the cpu-dispatch resolver for an out of line member
function is generated with the wrong name, causing a link failure.
2022-01-12 10:31:28 -08:00
Serge Guelton
d2cc6c2d0c Use a sorted array instead of a map to store AttrBuilder string attributes
Using and std::map<SmallString, SmallString> for target dependent attributes is
inefficient: it makes its constructor slightly heavier, and involves extra
allocation for each new string attribute. Storing the attribute key/value as
strings implies extra allocation/copy step.

Use a sorted vector instead. Given the low number of attributes generally
involved, this is cheaper, as showcased by

https://llvm-compile-time-tracker.com/compare.php?from=5de322295f4ade692dc4f1823ae4450ad3c48af2&to=05bc480bf641a9e3b466619af43a2d123ee3f71d&stat=instructions

Differential Revision: https://reviews.llvm.org/D116599
2022-01-10 14:49:53 +01:00
Kazu Hirata
40446663c7 [clang] Use true/false instead of 1/0 (NFC)
Identified with modernize-use-bool-literals.
2022-01-09 00:19:47 -08:00
serge-sans-paille
9290ccc3c1 Introduce the AttributeMask class
This class is solely used as a lightweight and clean way to build a set of
attributes to be removed from an AttrBuilder. Previously AttrBuilder was used
both for building and removing, which introduced odd situation like creation of
Attribute with dummy value because the only relevant part was the attribute
kind.

Differential Revision: https://reviews.llvm.org/D116110
2022-01-04 15:37:46 +01:00
Sami Tolvanen
ec2e26eaf6 [Clang] Add __builtin_function_start
Control-Flow Integrity (CFI) replaces references to address-taken
functions with pointers to the CFI jump table. This is a problem
for low-level code, such as operating system kernels, which may
need the address of an actual function body without the jump table
indirection.

This change adds the __builtin_function_start() builtin, which
accepts an argument that can be constant-evaluated to a function,
and returns the address of the function body.

Link: https://github.com/ClangBuiltLinux/linux/issues/1353

Depends on D108478

Reviewed By: pcc, rjmccall

Differential Revision: https://reviews.llvm.org/D108479
2021-12-20 12:55:33 -08:00
Nikita Popov
c3b624a191 [CodeGen] Avoid deprecated ConstantAddress constructor
Change all uses of the deprecated constructor to pass the
element type explicitly and drop it.

For cases where the correct element type was not immediately
obvious to me or would require a slightly larger change I'm
falling back to explicitly calling getPointerElementType() for now.
2021-12-15 10:42:41 +01:00
Peter Collingbourne
0a14674f27 CodeGen: Strip exception specifications from function types in CFI type names.
With C++17 the exception specification has been made part of the
function type, and therefore part of mangled type names.

However, it's valid to convert function pointers with an exception
specification to function pointers with the same argument and return
types but without an exception specification, which means that e.g. a
function of type "void () noexcept" can be called through a pointer
of type "void ()". We must therefore consider the two types to be
compatible for CFI purposes.

We can do this by stripping the exception specification before mangling
the type name, which is what this patch does.

Differential Revision: https://reviews.llvm.org/D115015
2021-12-03 14:50:52 -05:00
Ties Stuij
e3b2f0226b [clang][ARM] PACBTI-M frontend support
Handle branch protection option on the commandline as well as a function
attribute. One patch for both mechanisms, as they use the same underlying
parsing mechanism.

These are recorded in a set of LLVM IR module-level attributes like we do for
AArch64 PAC/BTI (see https://reviews.llvm.org/D85649):

- command-line options are "translated" to module-level LLVM IR
  attributes (metadata).

- functions have PAC/BTI specific attributes iff the
  __attribute__((target("branch-protection=...))) was used in the function
  declaration.

- command-line option -mbranch-protection to armclang targeting Arm,
following this grammar:

branch-protection ::= "-mbranch-protection=" <protection>
protection ::=  "none" | "standard" | "bti" [ "+" <pac-ret-clause> ]
                | <pac-ret-clause> [ "+" "bti"]
pac-ret-clause ::= "pac-ret" [ "+" <pac-ret-option> ]
pac-ret-option ::= "leaf" ["+" "b-key"] | "b-key" ["+" "leaf"]

b-key is simply a placeholder to make it consistent with AArch64's
version. In Arm, however, it triggers a warning informing that b-key is
unsupported and a-key will be selected instead.

- Handle _attribute_((target(("branch-protection=..."))) for AArch32 with the
same grammer as the commandline options.

This patch is part of a series that adds support for the PACBTI-M extension of
the Armv8.1-M architecture, as detailed here:

https://community.arm.com/arm-community-blogs/b/architectures-and-processors-blog/posts/armv8-1-m-pointer-authentication-and-branch-target-identification-extension

The PACBTI-M specification can be found in the Armv8-M Architecture Reference
Manual:

https://developer.arm.com/documentation/ddi0553/latest

The following people contributed to this patch:

- Momchil Velikov
- Victor Campos
- Ties Stuij

Reviewed By: vhscampos

Differential Revision: https://reviews.llvm.org/D112421
2021-12-01 10:37:16 +00:00
Erich Keane
fc53eb69c2 Reapply 'Implement target_clones multiversioning'
See discussion in D51650, this change was a little aggressive in an
error while doing a 'while we were here', so this removes that error
condition, as it is apparently useful.

This reverts commit bb4934601d731465e01e2e22c80ce2dbe687d73f.
2021-11-29 06:30:01 -08:00
Phoebe Wang
de34a940ae [X86] Add -mskip-rax-setup support to align with GCC
AMD64 ABI mandates caller to specify the number of used SSE registers
when passing variable arguments.
GCC also provides option -mskip-rax-setup to skip the setup of rax when
SSE is disabled. This helps to reduce the code size, see pr23258.

Reviewed By: nickdesaulniers

Differential Revision: https://reviews.llvm.org/D112413
2021-11-18 11:20:32 +08:00
Kazu Hirata
d0ac215dd5 [clang] Use isa instead of dyn_cast (NFC) 2021-11-14 09:32:40 -08:00
Adrian Kuegel
bb4934601d Revert "Implement target_clones multiversioning"
This reverts commit 9deab60ae710f8c4cc810cd680edfb64c803f42d.
There is a possibly unintended semantic change.
2021-11-12 11:05:58 +01:00
Erich Keane
9deab60ae7 Implement target_clones multiversioning
As discussed here: https://lwn.net/Articles/691932/

GCC6.0 adds target_clones multiversioning. This functionality is
an odd cross between the cpu_dispatch and 'target' MV, but is compatible
with neither.

This attribute allows you to list all options, then emits a separately
optimized version of each function per-option (similar to the
cpu_specific attribute). It automatically generates a resolver, just
like the other two.

The mangling however, is... ODD to say the least. The mangling format
is:
<normal_mangling>.<option string>.<option ordinal>.

Differential Revision:https://reviews.llvm.org/D51650
2021-11-11 11:11:16 -08:00
Yaxun (Sam) Liu
4b3881e9f3 Emit hidden hostcall argument for sanitized kernels
this patch - https://reviews.llvm.org/D110337 changes the way how hostcall
hidden argument is emitted for printf, but the sanitized kernels also use
hostcall buffer to report a error for invalid memory access, which is not
handled by the above patch and it leads to vdi runtime error:

Device::callbackQueue aborting with error : HSA_STATUS_ERROR_MEMORY_FAULT:
Agent attempted to access an inaccessible address. code: 0x2b

Patch by: Praveen Velliengiri

Reviewed by: Yaxun Liu, Matt Arsenault

Differential Revision: https://reviews.llvm.org/D112820
2021-11-10 17:05:57 -05:00
Yaxun (Sam) Liu
80072fde61 [CUDA][HIP] Allow comdat for kernels
Two identical instantiations of a template function can be emitted by two TU's
with linkonce_odr linkage without causing duplicate symbols in linker. MSVC
also requires these symbols be in comdat sections. Linux does not require
the symbols in comdat sections to be merged by linker but by default
clang puts them in comdat sections.

If a template kernel is instantiated identically in two TU's. MSVC requires
that them to be in comdat sections, otherwise MSVC linker will diagnose them as
duplicate symbols. However, currently clang does not put instantiated template
kernels in comdat sections, which causes link error for MSVC.

This patch allows putting instantiated template kernels into comdat sections.

Reviewed by: Artem Belevich, Reid Kleckner

Differential Revision: https://reviews.llvm.org/D112492
2021-11-10 16:42:23 -05:00
Itay Bookstein
9efce0baee [clang] Run LLVM Verifier in modes without CodeGen too
Previously, the Backend_Emit{Nothing,BC,LL} modes did
not run the LLVM verifier since it is usually added via
the TargetMachine::addPassesToEmitFile method according
to the DisableVerify parameter. This is called from
EmitAssemblyHelper::AddEmitPasses, which is only relevant
for BackendAction-s that require CodeGen.

Note:
* In these particular situations the verifier is added
  to the optimization pipeline rather than the codegen
  pipeline so that it runs prior to the BC/LL emission
  pass.
* This change applies to both the old and the new PMs.
* Because the clang tests use -emit-llvm ubiquitously,
  this change will enable the verifier for them.
* A small bug is fixed in emitIFuncDefinition so that
  the clang/test/CodeGen/ifunc.c test would pass:
  the emitIFuncDefinition incorrectly passed the
  GlobalDecl of the IFunc itself to the call to
  GetOrCreateLLVMFunction for creating the resolver.

Signed-off-by: Itay Bookstein <ibookstein@gmail.com>

Reviewed By: rjmccall

Differential Revision: https://reviews.llvm.org/D113352
2021-11-09 23:57:13 +02:00
Itay Bookstein
3b1fd19357 [CodeGen] Diagnose and reject non-function ifunc resolvers
Signed-off-by: Itay Bookstein <ibookstein@gmail.com>

Reviewed By: MaskRay, erichkeane

Differential Revision: https://reviews.llvm.org/D112868
2021-11-09 23:51:36 +02:00
Atmn Patel
737c4a2673 [clang][openmp][NFC] Remove arch-specific CGOpenMPRuntimeGPU files
The existing CGOpenMPRuntimeAMDGCN and CGOpenMPRuntimeNVPTX classes are
just code bloat. By removing them, the codebase gets a bit cleaner.

Reviewed By: jdoerfert, JonChesterfield, tianshilei1992

Differential Revision: https://reviews.llvm.org/D113421
2021-11-09 15:11:05 -05:00
Atmn Patel
ef717f3852 Revert "[clang][openmp][NFC] Remove arch-specific CGOpenMPRuntimeGPU files"
This reverts commit 81a7cad2ffc18f15b732f69d991c8398c979c5ca.
2021-11-09 02:10:42 -05:00
Atmn Patel
81a7cad2ff [clang][openmp][NFC] Remove arch-specific CGOpenMPRuntimeGPU files
The existing CGOpenMPRuntimeAMDGCN and CGOpenMPRuntimeNVPTX classes are
just code bloat. By removing them, the codebase gets a bit cleaner.

Reviewed By: jdoerfert, JonChesterfield, tianshilei1992

Differential Revision: https://reviews.llvm.org/D113421
2021-11-09 01:52:52 -05:00
Benjamin Kramer
8adb6d6de2 [clang] Use llvm::reverse. NFCI. 2021-11-07 14:24:33 +01:00
Itay Bookstein
848812a55e [Verifier] Add verification logic for GlobalIFuncs
Verify that the resolver exists, that it is a defined
Function, and that its return type matches the ifunc's
type. Add corresponding check to BitcodeReader, change
clang to emit the correct type, and fix tests to comply.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D112349
2021-10-31 20:00:57 -07:00
Aaron Ballman
aad244dfc5 Revert "AddGlobalAnnotations for function with or without function body."
This reverts commit 121b2252de0eed68f2ddf5f09e924a6c35423d47.

The following code causes a crash in some circumstances:

  struct k {
    ~k() __attribute__((annotate(""))) {}
  };
  void m() { k(); }
2021-10-21 07:08:18 -04:00
Itay Bookstein
08ed216000 [IR] Refactor GlobalIFunc to inherit from GlobalObject, Remove GlobalIndirectSymbol
As discussed in:
* https://reviews.llvm.org/D94166
* https://lists.llvm.org/pipermail/llvm-dev/2020-September/145031.html

The GlobalIndirectSymbol class lost most of its meaning in
https://reviews.llvm.org/D109792, which disambiguated getBaseObject
(now getAliaseeObject) between GlobalIFunc and everything else.
In addition, as long as GlobalIFunc is not a GlobalObject and
getAliaseeObject returns GlobalObjects, a GlobalAlias whose aliasee
is a GlobalIFunc cannot currently be modeled properly. Creating
aliases for GlobalIFuncs does happen in the wild (e.g. glibc). In addition,
calling getAliaseeObject on a GlobalIFunc will currently return nullptr,
which is undesirable because it should return the object itself for
non-aliases.

This patch refactors the GlobalIFunc class to inherit directly from
GlobalObject, and removes GlobalIndirectSymbol (while inlining the
relevant parts into GlobalAlias and GlobalIFunc). This allows for
calling getAliaseeObject() on a GlobalIFunc to return the GlobalIFunc
itself, making getAliaseeObject() more consistent and enabling
alias-to-ifunc to be properly modeled in the IR.

I exercised some judgement in the API clients of GlobalIndirectSymbol:
some were 'monomorphized' for GlobalAlias and GlobalIFunc, and
some remained shared (with the type adapted to become GlobalValue).

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D108872
2021-10-20 10:29:47 -07:00
Kazu Hirata
d245f2e859 [clang] Use llvm::erase_if (NFC) 2021-10-17 13:50:29 -07:00
Chris Bieneman
121b2252de AddGlobalAnnotations for function with or without function body.
When AnnotateAttr is on a function, AddGlobalAnnotations is only called
in CodeGenModule::EmitGlobalFunctionDefinition which means AnnotateAttr
on function declaration without function body will be ignored.
The patch will move AddGlobalAnnotations  to
CodeGenModule::SetFunctionAttributes, so with or without function body,
the AnnotateAttr will get code gen for a function.

It'll help case when AnnotateAttr is on external function, and the
AnnotateAttr will be consumed in IR level.

For example, a pass to collect num of uses for functions with
__attribute((annotate("count_use"))) after optimizations,
As long as there's __attribute((annotate("count_use"))), function with
or without function body should be counted.

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D111109

Patch by:  python3kgae (Xiang Li)
2021-10-11 14:50:34 -05:00
Arthur Eubanks
05392466f0 Reland [IR] Increase max alignment to 4GB
Currently the max alignment representable is 1GB, see D108661.
Setting the align of an object to 4GB is desirable in some cases to make sure the lower 32 bits are clear which can be used for some optimizations, e.g. https://crbug.com/1016945.

This uses an extra bit in instructions that carry an alignment. We can store 15 bits of "free" information, and with this change some instructions (e.g. AtomicCmpXchgInst) use 14 bits.
We can increase the max alignment representable above 4GB (up to 2^62) since we're only using 33 of the 64 values, but I've just limited it to 4GB for now.

The one place we have to update the bitcode format is for the alloca instruction. It stores its alignment into 5 bits of a 32 bit bitfield. I've added another field which is 8 bits and should be future proof for a while. For backward compatibility, we check if the old field has a value and use that, otherwise use the new field.

Updating clang's max allowed alignment will come in a future patch.

Reviewed By: hans

Differential Revision: https://reviews.llvm.org/D110451
2021-10-06 13:29:23 -07:00
Arthur Eubanks
569346f274 Revert "Reland [IR] Increase max alignment to 4GB"
This reverts commit 8d64314ffea55f2ad94c1b489586daa8ce30f451.
2021-10-06 11:38:11 -07:00
Arthur Eubanks
8d64314ffe Reland [IR] Increase max alignment to 4GB
Currently the max alignment representable is 1GB, see D108661.
Setting the align of an object to 4GB is desirable in some cases to make sure the lower 32 bits are clear which can be used for some optimizations, e.g. https://crbug.com/1016945.

This uses an extra bit in instructions that carry an alignment. We can store 15 bits of "free" information, and with this change some instructions (e.g. AtomicCmpXchgInst) use 14 bits.
We can increase the max alignment representable above 4GB (up to 2^62) since we're only using 33 of the 64 values, but I've just limited it to 4GB for now.

The one place we have to update the bitcode format is for the alloca instruction. It stores its alignment into 5 bits of a 32 bit bitfield. I've added another field which is 8 bits and should be future proof for a while. For backward compatibility, we check if the old field has a value and use that, otherwise use the new field.

Updating clang's max allowed alignment will come in a future patch.

Reviewed By: hans

Differential Revision: https://reviews.llvm.org/D110451
2021-10-06 11:03:51 -07:00
Arthur Eubanks
72cf8b6044 Revert "[IR] Increase max alignment to 4GB"
This reverts commit df84c1fe78130a86445d57563dea742e1b85156a.

Breaks some bots
2021-10-06 10:21:35 -07:00
Arthur Eubanks
df84c1fe78 [IR] Increase max alignment to 4GB
Currently the max alignment representable is 1GB, see D108661.
Setting the align of an object to 4GB is desirable in some cases to make sure the lower 32 bits are clear which can be used for some optimizations, e.g. https://crbug.com/1016945.

This uses an extra bit in instructions that carry an alignment. We can store 15 bits of "free" information, and with this change some instructions (e.g. AtomicCmpXchgInst) use 14 bits.
We can increase the max alignment representable above 4GB (up to 2^62) since we're only using 33 of the 64 values, but I've just limited it to 4GB for now.

The one place we have to update the bitcode format is for the alloca instruction. It stores its alignment into 5 bits of a 32 bit bitfield. I've added another field which is 8 bits and should be future proof for a while. For backward compatibility, we check if the old field has a value and use that, otherwise use the new field.

Updating clang's max allowed alignment will come in a future patch.

Reviewed By: hans

Differential Revision: https://reviews.llvm.org/D110451
2021-10-06 09:54:14 -07:00
Arthur Eubanks
aa53785f23 Reland [clang] Rework dontcall attributes
To avoid using the AST when emitting diagnostics, split the "dontcall"
attribute into "dontcall-warn" and "dontcall-error", and also add the
frontend attribute value as the LLVM attribute value. This gives us all
the information to report diagnostics we need from within the IR (aside
from access to the original source).

One downside is we directly use LLVM's demangler rather than using the
existing Clang diagnostic pretty printing of symbols.

Previous revisions didn't properly declare the new dependencies.

Reviewed By: nickdesaulniers

Differential Revision: https://reviews.llvm.org/D110364
2021-09-28 15:31:30 -07:00
Arthur Eubanks
7833d20f1f Revert "[clang] Rework dontcall attributes"
This reverts commit 2943071e2ee0c7f31f34062a44d12aeb0e3a66fd.

Breaks bots
2021-09-28 14:49:27 -07:00
Arthur Eubanks
2943071e2e [clang] Rework dontcall attributes
To avoid using the AST when emitting diagnostics, split the "dontcall"
attribute into "dontcall-warn" and "dontcall-error", and also add the
frontend attribute value as the LLVM attribute value. This gives us all
the information to report diagnostics we need from within the IR (aside
from access to the original source).

One downside is we directly use LLVM's demangler rather than using the
existing Clang diagnostic pretty printing of symbols.

Reviewed By: nickdesaulniers

Differential Revision: https://reviews.llvm.org/D110364
2021-09-28 14:21:10 -07:00
serge-sans-paille
c3717b6858 Simplify handling of builtin with inline redefinition
(This is a recommit of 3d6f49a56995b845 that should no longer break validation since
bd379915de38a9af3d65e1).

It is a common practice in glibc header to provide an inline redefinition of an
existing function. It is especially the case for fortified function.

Clang currently has an imperfect approach to the problem, using a combination of
trivially recursive function detection and noinline attribute.

Simplify the logic by suffixing these functions by `.inline` during codegen, so
that they are not recognized as builtin by llvm.

After that patch, clang passes all tests from https://github.com/serge-sans-paille/fortify-test-suite

Differential Revision: https://reviews.llvm.org/D109967
2021-09-28 21:00:47 +02:00
Kevin Athey
0d76d4833d Revert "Simplify handling of builtin with inline redefinition"
This reverts commit 3d6f49a56995b845c40be5827ded5d1e3f692cec.

Broke bot: https://lab.llvm.org/buildbot/#/builders/5/builds/12360
2021-09-28 11:30:37 -07:00
serge-sans-paille
3d6f49a569 Simplify handling of builtin with inline redefinition
It is a common practice in glibc header to provide an inline redefinition of an
existing function. It is especially the case for fortified function.

Clang currently has an imperfect approach to the problem, using a combination of
trivially recursive function detection and noinline attribute.

Simplify the logic by suffixing these functions by `.inline` during codegen, so
that they are not recognized as builtin by llvm.

After that patch, clang passes all tests from https://github.com/serge-sans-paille/fortify-test-suite

Differential Revision: https://reviews.llvm.org/D109967
2021-09-28 13:24:25 +02:00
Erich Keane
e3b10525b4 Make multiversioning work with internal linkage
We previously made all multiversioning resolvers/ifuncs have weak
ODR linkage in IR, since we NEED to emit the whole resolver every time
we see a call, but it is not necessarily the place where all the
definitions live.

HOWEVER, when doing so, we neglected the case where the versions have
internal linkage.  This patch ensures we do this, so you don't get weird
behavior with static functions.
2021-09-17 05:56:38 -07:00
Justas Janickas
f9bc1b3bee [OpenCL] Defines helper function for kernel language compatible OpenCL version
This change defines a helper function getOpenCLCompatibleVersion()
inside LangOptions class. The function contains mapping between
C++ for OpenCL versions and their corresponding compatible OpenCL
versions. This mapping function should be updated each time a new
C++ for OpenCL language version is introduced. The helper function
is expected to simplify conditions on OpenCL C and C++ for OpenCL
versions inside compiler code.

Code refactoring performed.

Differential Revision: https://reviews.llvm.org/D108693
2021-08-31 10:08:38 +01:00
Andrei Elovikov
1724a16437 [NFC][clang] Move IR-independent parts of target MV support to X86TargetParser.cpp
...that is located under llvm/lib/Support/.

Reviewed By: erichkeane

Differential Revision: https://reviews.llvm.org/D108423
2021-08-30 09:48:48 -07:00
Alex Richardson
7cab90a7b1 Fix __attribute__((annotate("")) with non-zero globals AS
The existing code attempting to bitcast from a value in the default globals AS
to i8 addrspace(0)* was triggering an assertion failure in our downstream fork.
I found this while compiling poppler for CHERI-RISC-V (we use AS200 for all
globals). The test case uses AMDGPU since that is one of the in-tree targets
with a non-zero default globals address space.
The new test previously triggered a "Invalid constantexpr bitcast!" assertion
and now correctly generates code with addrspace(1) pointers.

Reviewed By: rjmccall

Differential Revision: https://reviews.llvm.org/D105972
2021-08-26 10:09:40 +01:00
Nick Desaulniers
846e562dcc [Clang] add support for error+warning fn attrs
Add support for the GNU C style __attribute__((error(""))) and
__attribute__((warning(""))). These attributes are meant to be put on
declarations of functions whom should not be called.

They are frequently used to provide compile time diagnostics similar to
_Static_assert, but which may rely on non-ICE conditions (ie. relying on
compiler optimizations). This is also similar to diagnose_if function
attribute, but can diagnose after optimizations have been run.

While users may instead simply call undefined functions in such cases to
get a linkage failure from the linker, these provide a much more
ergonomic and actionable diagnostic to users and do so at compile time
rather than at link time. Users instead may be able use inline asm .err
directives.

These are used throughout the Linux kernel in its implementation of
BUILD_BUG and BUILD_BUG_ON macros. These macros generally cannot be
converted to use _Static_assert because many of the parameters are not
ICEs. The Linux kernel still needs to be modified to make use of these
when building with Clang; I have a patch that does so I will send once
this feature is landed.

To do so, we create a new IR level Function attribute, "dontcall" (both
error and warning boil down to one IR Fn Attr).  Then, similar to calls
to inline asm, we attach a !srcloc Metadata node to call sites of such
attributed callees.

The backend diagnoses these during instruction selection, while we still
know that a call is a call (vs say a JMP that's a tail call) in an arch
agnostic manner.

The frontend then reconstructs the SourceLocation from that Metadata,
and determines whether to emit an error or warning based on the callee's
attribute.

Link: https://bugs.llvm.org/show_bug.cgi?id=16428
Link: https://github.com/ClangBuiltLinux/linux/issues/1173

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D106030
2021-08-25 10:34:18 -07:00
Jonas Hahnfeld
ea08c4cd1c [CUDA] Fix static device variables with -fgpu-rdc
NVPTX does not allow dots in the identifier, so ptxas errors out with
   fatal   : Parsing error near '.static': syntax error
because it parses .static as a directive. Avoid this problem by using
two underscores, similar to what OpenMP does for outlined functions.

Differential Revision: https://reviews.llvm.org/D108456
2021-08-25 09:31:22 +02:00
Andy Wingo
8da70fed70 [clang][NFC] Tighten up code for GetGlobalVarAddressSpace
The LangAS local is only used in the OpenCL case; move its decl
inwards.

Differential Revision: https://reviews.llvm.org/D108449
2021-08-23 14:55:58 +02:00
Andy Wingo
d3d4d98576 [clang][NFC] GetOrCreateLLVMGlobal takes LangAS
Pass a LangAS instead of a target address space to
GetOrCreateLLVMGlobal, to remove a place where the frontend assumes that
target address space 0 is special.

Differential Revision: https://reviews.llvm.org/D108445
2021-08-23 14:55:58 +02:00
Arthur Eubanks
de0ae9e89e [NFC] Cleanup more AttributeList::addAttribute() 2021-08-17 21:05:41 -07:00