Commit Graph

1633 Commits

Author SHA1 Message Date
Vedant Kumar 273c299d5d [PM/CC1] Add -f[no-]split-cold-code CC1 option to toggle splitting
This patch adds -f[no-]split-cold-code CC1 options to clang. This allows
the splitting pass to be toggled on/off. The current method of passing
`-mllvm -hot-cold-split=true` to clang isn't ideal as it may not compose
correctly (say, with `-O0` or `-Oz`).

To implement the -fsplit-cold-code option, an attribute is applied to
functions to indicate that they may be considered for splitting. This
removes some complexity from the old/new PM pipeline builders, and
behaves as expected when LTO is enabled.

Co-authored by: Saleem Abdulrasool <compnerd@compnerd.org>
Differential Revision: https://reviews.llvm.org/D57265
Reviewed By: Aditya Kumar, Vedant Kumar
Reviewers: Teresa Johnson, Aditya Kumar, Fedor Sergeev, Philip Pfaffe, Vedant Kumar
2020-10-15 23:13:33 +00:00
Leonard Chan 79829a4704 Revert "[clang] Add -fc++-abi= flag for specifying which C++ ABI to use"
This reverts commits 683b308c07 and
8487bfd4e9.

We will go for a more restricted approach that does not give freedom to
everyone to change ABIs on whichever platform.

See the discussion on https://reviews.llvm.org/D85802.
2020-10-15 14:24:38 -07:00
Leonard Chan 683b308c07 [clang] Add -fc++-abi= flag for specifying which C++ ABI to use
This implements the flag proposed in RFC http://lists.llvm.org/pipermail/cfe-dev/2020-August/066437.html.

The goal is to add a way to override the default target C++ ABI through
a compiler flag. This makes it easier to test and transition between different
C++ ABIs through compile flags rather than build flags.

In this patch:
- Store `-fc++-abi=` in a LangOpt. This isn't stored in a
  CodeGenOpt because there are instances outside of codegen where Clang
  needs to know what the ABI is (particularly through
  ASTContext::createCXXABI), and we should be able to override the
  target default if the flag is provided at that point.
- Expose the existing ABIs in TargetCXXABI as values that can be passed
  through this flag.
  - Create a .def file for these ABIs to make it easier to check flag
    values.
  - Add an error for diagnosing bad ABI flag values.

Differential Revision: https://reviews.llvm.org/D85802
2020-10-14 12:31:21 -07:00
Fangrui Song a2cc883368 [CUDA] Don't call __cudaRegisterVariable on C++17 inline variables
D17779: host-side shadow variables of external declarations of device-side
global variables have internal linkage and are referenced by
`__cuda_register_globals`.

nvcc from CUDA 11 does not allow `__device__ inline` or `__device__ constexpr`
(C++17 inline variables) but clang has incorrectly supported them for a while:

```
error: A __device__ variable cannot be marked constexpr
error: An inline __device__/__constant__/__managed__ variable must have internal linkage when the program is compiled in whole program mode (-rdc=false)
```

If such a variable (which has a comdat group) is discarded (a copy from another
translation unit is prevailing and selected), accessing the variable from
outside the section group (`__cuda_register_globals`) is a violation of the ELF
specification and will be rejected by linkers:

> A symbol table entry with STB_LOCAL binding that is defined relative to one of a group's sections, and that is contained in a symbol table section that is not part of the group, must be discarded if the group members are discarded. References to this symbol table entry from outside the group are not allowed.

As a workaround, don't register such inline variables for now.
(If we register the variables in all TUs, we will keep multiple instances of the shadow and break the C++ semantics for inline variables).
We should reject such variables in Sema but our internal users need some time to migrate.

Reviewed By: tra

Differential Revision: https://reviews.llvm.org/D88786
2020-10-05 12:53:59 -07:00
Momchil Velikov a88c722e68 [AArch64] PAC/BTI code generation for LLVM generated functions
PAC/BTI-related codegen in the AArch64 backend is controlled by a set
of LLVM IR function attributes, added to the function by Clang, based
on command-line options and GCC-style function attributes. However,
functions, generated in the LLVM middle end (for example,
asan.module.ctor or __llvm_gcov_write_out) do not get any attributes
and the backend incorrectly does not do any PAC/BTI code generation.

This patch record the default state of PAC/BTI codegen in a set of
LLVM IR module-level attributes, based on command-line options:

* "sign-return-address", with non-zero value means generate code to
  sign return addresses (PAC-RET), zero value means disable PAC-RET.

* "sign-return-address-all", with non-zero value means enable PAC-RET
  for all functions, zero value means enable PAC-RET only for
  functions, which spill LR.

* "sign-return-address-with-bkey", with non-zero value means use B-key
  for signing, zero value mean use A-key.

This set of attributes are always added for AArch64 targets (as
opposed, for example, to interpreting a missing attribute as having a
value 0) in order to be able to check for conflicts when combining
module attributed during LTO.

Module-level attributes are overridden by function level attributes.
All the decision making about whether to not to generate PAC and/or
BTI code is factored out into AArch64FunctionInfo, there shouldn't be
any places left, other than AArch64FunctionInfo, which directly
examine PAC/BTI attributes, except AArch64AsmPrinter.cpp, which
is/will-be handled by a separate patch.

Differential Revision: https://reviews.llvm.org/D85649
2020-09-25 11:47:14 +01:00
Yaxun (Sam) Liu 301e23305d [CUDA][HIP] Fix static device var used by host code only
A static device variable may be accessed in host code through
cudaMemCpyFromSymbol etc. Currently clang does not
emit the static device variable if it is only referenced by
host code, which causes host code to fail at run time.

This patch fixes that.

Differential Revision: https://reviews.llvm.org/D88115
2020-09-23 08:18:19 -04:00
Erik Pilkington 2d11ae0a40 Fix a -Wparenthesis warning in 8ff44e644b, NFC 2020-09-02 15:01:54 -04:00
Erik Pilkington 8ff44e644b [IRGen] Fix an assert when __attribute__((used)) is used on an ObjC method
This assert doesn't really make sense for functions in general, since they
start life as declarations, and there isn't really any reason to require them
to be defined before attributes are applied to them.

rdar://67895846
2020-09-02 12:19:11 -04:00
Craig Topper 17ceda99d3 [CodeGen] Use an AttrBuilder to bulk remove 'target-cpu', 'target-features', and 'tune-cpu' before re-adding in CodeGenModule::setNonAliasAttributes.
I think the removeAttributes interface should be faster than
calling removeAttribute 3 times.
2020-08-27 12:54:20 -07:00
Craig Topper 724f570ad2 [X86] Add support 'tune' in target attribute
This adds parsing and codegen support for tune in target attribute.

I've implemented this so that arch in the target attribute implicitly disables tune from the command line. I'm not sure what gcc does here. But since -march implies -mtune. I assume 'arch' in the target attribute implies tune in the target attribute.

Differential Revision: https://reviews.llvm.org/D86187
2020-08-19 15:58:19 -07:00
Craig Topper 4cbceb74bb [X86] Add basic support for -mtune command line option in clang
Building on the backend support from D85165. This parses the command line option in the driver, passes it on to CC1 and adds a function attribute.

-Still need to support tune on the target attribute.
-Need to use "generic" as the tuning by default. But need to change generic in the backend first.
-Need to set tune if march is specified and mtune isn't.
-May need to disable getHostCPUName's ability to guess CPU name from features when it doesn't have a family/model match for mtune=native. That's what gcc appears to do.

Differential Revision: https://reviews.llvm.org/D85384
2020-08-18 15:13:19 -07:00
Kai Nacke b3aece0531 [SystemZ/ZOS] Add binary format goff and operating system zos to the triple
Adds the binary format goff and the operating system zos to the triple
class. goff is selected as default binary format if zos is choosen as
operating system. No further functionality is added.

Reviewers: efriedma, tahonermann, hubert.reinterpertcast, MaskRay

Reviewed By: efriedma, tahonermann, hubert.reinterpertcast

Differential Revision: https://reviews.llvm.org/D82081
2020-08-11 05:26:26 -04:00
Nick Desaulniers 4f2ad15db5 [Clang] implement -fno-eliminate-unused-debug-types
Fixes pr/11710.
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>

Resubmit after breaking Windows and OSX builds.

Reviewed By: dblaikie

Differential Revision: https://reviews.llvm.org/D80242
2020-08-10 15:08:48 -07:00
Nick Desaulniers abb9bf4bcf Revert "[Clang] implement -fno-eliminate-unused-debug-types"
This reverts commit e486921fd6.

Breaks windows builds and osx builds.
2020-08-07 16:11:41 -07:00
Nick Desaulniers e486921fd6 [Clang] implement -fno-eliminate-unused-debug-types
Fixes pr/11710.
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>

Reviewed By: dblaikie

Differential Revision: https://reviews.llvm.org/D80242
2020-08-07 14:13:48 -07:00
Saiyedul Islam 160ff83765 [OpenMP][AMDGCN] Support OpenMP offloading for AMDGCN architecture - Part 3
Provides AMDGCN and NVPTX specific specialization of getGPUWarpSize,
getGPUThreadID, and getGPUNumThreads methods. Adds tests for AMDGCN
codegen for these methods in generic and simd modes. Also changes the
precondition in InitTempAlloca to be slightly more permissive. Useful for
AMDGCN OpenMP codegen where allocas are created with a cast to an
address space.

Reviewed By: ABataev

Differential Revision: https://reviews.llvm.org/D84260
2020-08-03 05:38:39 +00:00
Alexey Bader 8d27be8dba [OpenCL] Add global_device and global_host address spaces
This patch introduces 2 new address spaces in OpenCL: global_device and global_host
which are a subset of a global address space, so the address space scheme will be
looking like:

```
generic->global->host
                          ->device
             ->private
             ->local
constant
```

Justification: USM allocations may be associated with both host and device memory. We
want to give users a way to tell the compiler the allocation type of a USM pointer for
optimization purposes. (Link to the Unified Shared Memory extension:
https://github.com/intel/llvm/blob/sycl/sycl/doc/extensions/USM/cl_intel_unified_shared_memory.asciidoc)

Before this patch USM pointer could be only in opencl_global
address space, hence a device backend can't tell if a particular pointer
points to host or device memory. On FPGAs at least we can generate more
efficient hardware code if the user tells us where the pointer can point -
being able to distinguish between these types of pointers at compile time
allows us to instantiate simpler load-store units to perform memory
transactions.

Patch by Dmitry Sidorov.

Reviewed By: Anastasia

Differential Revision: https://reviews.llvm.org/D82174
2020-07-29 17:24:53 +03:00
Xiangling Liao ec6ada6264 [AIX] report_fatal_error on `-fregister_global_dtors_with_atexit` for static init
On AIX, the semantic of global_dtors contains __sterm functions associated with C++
cleanup actions and user-declared __attribute__((destructor)) functions. We should
never merely register __sterm with atexit(), so currently
-fregister_global_dtors_with_atexit does not work well on AIX: It would cause
finalization actions to not occur when unloading shared libraries.  We need to figure
out a way to handle that when we start supporting user-declared
__attribute__((destructor)) functions.

Currently we report_fatal_error on this option temporarily.

Differential Revision: https://reviews.llvm.org/D83974
2020-07-17 16:14:49 -04:00
sstefan1 6aab27ba85 [OpenMPIRBuilder][Fix] Move llvm::omp::types to OpenMPIRBuilder.
Summary:
D82193 exposed a problem with global type definitions in
`OMPConstants.h`. This causes a race when running in thinLTO mode.
Types now live inside of OpenMPIRBuilder to prevent this from happening.

Reviewers: jdoerfert

Subscribers: yaxunl, hiraditya, guansong, dexonsmith, aaron.ballman, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D83176
2020-07-08 17:23:55 +02:00
Nigel Perks dc3f8913d2 Fix crash on XCore on unused inline in EmitTargetMetadata
EmitTargetMetadata passed to emitTargetMD a null pointer as returned
from GetGlobalValue, for an unused inline function which has been
removed from the module at that point.

A FIXME in CodeGenModule.cpp commented that the calling code in
EmitTargetMetadata should be moved into the one target that needs it
(XCore). A review comment agreed. So the calling loop has been moved
into the XCore subclass. The check for null is done in that loop.

Differential Revision: https://reviews.llvm.org/D77068
2020-06-24 12:48:17 -07:00
Michael Liao ebc9e0f1f0 Fix coding style. NFC.
- Remove `else` after `return`.
2020-06-24 13:13:42 -04:00
Eli Friedman bf8b63ed29 [clang codegen] Fix alignment of "Address" for incomplete array pointer.
The code was assuming all incomplete types don't have meaningful
alignment, but incomplete arrays do have meaningful alignment.

Fixes https://bugs.llvm.org/show_bug.cgi?id=45710

Differential Revision: https://reviews.llvm.org/D79052
2020-06-23 17:16:17 -07:00
Xiangling Liao 22337bfe7d [AIX][Frontend] Static init implementation for AIX considering no priority
1. Provides no piroirity supoort && disables three priority related
   attributes: init_priority, ctor attr, dtor attr;
2. '-qunique' in XL compiler equivalent behavior of emitting sinit
    and sterm functions name using getUniqueModuleId() util function
    in LLVM (currently no support for InternalLinkage and WeakODRLinkage
    symbols);
3. Add testcases to emit IR sample with __sinit80000000, __dtor, and
    __sterm80000000;
4. Temporarily side-steps the need to implement the functionality of
   llvm.global_ctors and llvm.global_dtors arrays. The uses of that
   functionality in this patch (with respect to the name of the functions
   involved) are not representative of how the functionality will be used
   once implemented.

Differential Revision: https://reviews.llvm.org/D74166
2020-06-19 08:27:07 -04:00
Jun Ma 4a1776979f [CodeGen][TLS] Set TLS Model for __tls_guard as well.
Differential Revision: https://reviews.llvm.org/D81543
2020-06-17 08:31:13 +08:00
Tyker 51e4aa87e0 attempt to fix failing buildbots after 3bab88b7ba
Prevent IR-gen from emitting consteval declarations

Summary: with this patch instead of emitting calls to consteval function. the IR-gen will emit a store of the already computed result.
2020-06-15 12:58:37 +02:00
Kirill Bobyrev 550c4562d1 Revert "Prevent IR-gen from emitting consteval declarations"
This reverts commit 3bab88b7ba.

This patch causes test failures:
http://lab.llvm.org:8011/builders/clang-cmake-armv7-quick/builds/17260
2020-06-15 12:14:15 +02:00
Tyker 3bab88b7ba Prevent IR-gen from emitting consteval declarations
Summary: with this patch instead of emitting calls to consteval function. the IR-gen will emit a store of the already computed result.

Reviewers: rsmith

Reviewed By: rsmith

Subscribers: cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D76420
2020-06-15 10:47:14 +02:00
Jian Cai 4db2b70248 Add a flag to debug automatic variable initialization
Summary:
Add -ftrivial-auto-var-init-stop-after= to limit the number of times
stack variables are initialized when -ftrivial-auto-var-init= is used to
initialize stack variables to zero or a pattern. This flag can be used
to bisect uninitialized uses of a stack variable exposed by automatic
variable initialization, such as http://crrev.com/c/2020401.

Reviewers: jfb, vitalybuka, kcc, glider, rsmith, rjmccall, pcc, eugenis, vlad.tsyrklevich

Reviewed By: jfb

Subscribers: phosek, hubert.reinterpretcast, srhines, MaskRay, george.burgess.iv, dexonsmith, inglorion, gbiv, llozano, manojgupta, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D77168
2020-06-08 12:30:56 -07:00
Ties Stuij ecd682bbf5 [ARM] Add __bf16 as new Bfloat16 C Type
Summary:
This patch upstreams support for a new storage only bfloat16 C type.
This type is used to implement primitive support for bfloat16 data, in
line with the Bfloat16 extension of the Armv8.6-a architecture, as
detailed here:

https://community.arm.com/developer/ip-products/processors/b/processors-ip-blog/posts/arm-architecture-developments-armv8-6-a

The bfloat type, and its properties are specified in the Arm Architecture
Reference Manual:

https://developer.arm.com/docs/ddi0487/latest/arm-architecture-reference-manual-armv8-for-armv8-a-architecture-profile

In detail this patch:
- introduces an opaque, storage-only C-type __bf16, which introduces a new bfloat IR type.

This is part of a patch series, starting with command-line and Bfloat16
assembly support. The subsequent patches will upstream intrinsics
support for BFloat16, followed by Matrix Multiplication and the
remaining Virtualization features of the armv8.6-a architecture.

The following people contributed to this patch:
- Luke Cheeseman
- Momchil Velikov
- Alexandros Lamprineas
- Luke Geeson
- Simon Tatham
- Ties Stuij

Reviewers: SjoerdMeijer, rjmccall, rsmith, liutianle, RKSimon, craig.topper, jfb, LukeGeeson, fpetrogalli

Reviewed By: SjoerdMeijer

Subscribers: labrinea, majnemer, asmith, dexonsmith, kristof.beyls, arphaman, danielkiss, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D76077
2020-06-05 10:32:43 +01:00
Nick Desaulniers ef1d4bec89 [Clang][CGM] style cleanups NFC
Summary:
Forked from:
https://reviews.llvm.org/D80242

Use the getter for access to DebugInfo consistently.
Use break in switch in CodeGenModule::EmitTopLevelDecl consistently.

Reviewers: dblaikie

Reviewed By: dblaikie

Subscribers: cfe-commits, srhines

Tags: #clang

Differential Revision: https://reviews.llvm.org/D80840
2020-06-01 09:33:08 -07:00
James Y Knight aca3d067ef Fix Darwin 'constinit thread_local' variables.
Unlike other platforms using ItaniumCXXABI, Darwin does not allow the
creation of a thread-wrapper function for a variable in the TU of
users. Because of this, it can set the linkage of the thread-local
symbol to internal, with the assumption that no TUs other than the one
defining the variable will need it.

However, constinit thread_local variables do not require the use of
the thread-wrapper call, so users reference the variable
directly. Thus, it must not be converted to internal, or users will
get a link failure.

This was a regression introduced by the optimization in
00223827a9.

Differential Revision: https://reviews.llvm.org/D80417
2020-05-27 11:59:30 -04:00
Fangrui Song 9d55e4ee13 Make explicit -fno-semantic-interposition (in -fpic mode) infer dso_local
-fno-semantic-interposition is currently the CC1 default. (The opposite
disables some interprocedural optimizations.) However, it does not infer
dso_local: on most targets accesses to ExternalLinkage functions/variables
defined in the current module still need PLT/GOT.

This patch makes explicit -fno-semantic-interposition infer dso_local,
so that PLT/GOT can be eliminated if targets implement local aliases
for AsmPrinter::getSymbolPreferLocal (currently only x86).

Currently we check whether the module flag "SemanticInterposition" is 0.
If yes, infer dso_local. In the future, we can infer dso_local unless
"SemanticInterposition" is 1: frontends other than clang will also
benefit from the optimization if they don't bother setting the flag.
(There will be risks if they do want ELF interposition: they need to set
"SemanticInterposition" to 1.)
2020-05-25 20:48:18 -07:00
Eli Friedman 62f3ef2b53 [CGCall] Annotate references with "align" attribute.
If we're going to assume references are dereferenceable, we should also
assume they're aligned: otherwise, we can't actually dereference them.

See also D80072.

Differential Revision: https://reviews.llvm.org/D80166
2020-05-19 20:21:30 -07:00
George Burgess IV 94908088a8 [CodeGen] fix inline builtin-related breakage from D78162
In cases where we have multiple decls of an inline builtin, we may need
to go hunting for the one with a definition when setting function
attributes.

An additional test-case was provided on
https://github.com/ClangBuiltLinux/linux/issues/979
2020-04-16 11:54:10 -07:00
Richard Smith bab6df86ae Rework how UuidAttr, CXXUuidofExpr, and GUID template arguments and constants are represented.
Summary:
Previously, we treated CXXUuidofExpr as quite a special case: it was the
only kind of expression that could be a canonical template argument, it
could be a constant lvalue base object, and so on. In addition, we
represented the UUID value as a string, whose source form we did not
preserve faithfully, and that we partially parsed in multiple different
places.

With this patch, we create an MSGuidDecl object to represent the
implicit object of type 'struct _GUID' created by a UuidAttr. Each
UuidAttr holds a pointer to its 'struct _GUID' and its original
(as-written) UUID string. A non-value-dependent CXXUuidofExpr behaves
like a DeclRefExpr denoting that MSGuidDecl object. We cache an APValue
representation of the GUID on the MSGuidDecl and use it from constant
evaluation where needed.

This allows removing a lot of the special-case logic to handle these
expressions. Unfortunately, many parts of Clang assume there are only
a couple of interesting kinds of ValueDecl, so the total amount of
special-case logic is not really reduced very much.

This fixes a few bugs and issues:
 * PR38490: we now support reading from GUID objects returned from
   __uuidof during constant evaluation.
 * Our Itanium mangling for a non-instantiation-dependent template
   argument involving __uuidof no longer depends on which CXXUuidofExpr
   template argument we happened to see first.
 * We now predeclare ::_GUID, and permit use of __uuidof without
   any header inclusion, better matching MSVC's behavior. We do not
   predefine ::__s_GUID, though; that seems like a step too far.
 * Our IR representation for GUID constants now uses the correct IR type
   wherever possible. We will still fall back to using the
      {i32, i16, i16, [8 x i8]}
   layout if a definition of struct _GUID is not available. This is not
   ideal: in principle the two layouts could have different padding.

Reviewers: rnk, jdoerfert

Subscribers: arphaman, cfe-commits, aeubanks

Tags: #clang

Differential Revision: https://reviews.llvm.org/D78171
2020-04-15 12:20:42 -07:00
George Burgess IV 2dd17ff081 [CodeGen] only add nobuiltin to inline builtins if we'll emit them
There are some inline builtin definitions that we can't emit
(isTriviallyRecursive & callers go into why). Marking these
nobuiltin is only useful if we actually emit the body, so don't mark
these as such unless we _do_ plan on emitting that.

This suboptimality was encountered in Linux (see some discussion on
D71082, and https://github.com/ClangBuiltLinux/linux/issues/979).

Differential Revision: https://reviews.llvm.org/D78162
2020-04-15 11:05:22 -07:00
George Burgess IV 91c8c74180 [CodeGen] clarify a comment; NFC
Prompted by discussion on https://reviews.llvm.org/D78148.
2020-04-14 14:33:01 -07:00
Ayke van Laethem cfc002714a
[AVR] Support aliases in non-zero address space
This fixes code like the following on AVR:

void foo(void) {
}
void bar(void) __attribute__((alias("foo")));

Code like this is present in compiler-rt, which I'm trying to build.

Differential Revision: https://reviews.llvm.org/D76182
2020-04-14 00:42:19 +02:00
Michael Liao c97be2c377 [hip] Remove `hip_pinned_shadow`.
Summary:
- Use `device_builtin_surface` and `device_builtin_texture` for
  surface/texture reference support. So far, both the host and device
  use the same reference type, which could be revised later when
  interface/implementation is stablized.

Reviewers: yaxunl

Subscribers: cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D77583
2020-04-07 09:51:49 -04:00
Eli Friedman 83fa811e5b [clang][opaque pointers] Fix up a bunch of "getType()->getElementType()"
In contexts where we know an LLVM type is a pointer, there's generally
some simpler way to get the pointee type.
2020-04-03 18:00:33 -07:00
Michael Liao 5be9b8cbe2 [cuda][hip] Add CUDA builtin surface/texture reference support.
Summary: - Re-commit after fix Sema checks on partial template specialization.

Reviewers: tra, rjmccall, yaxunl, a.sidorin

Subscribers: cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D76365
2020-03-27 17:18:49 -04:00
Artem Belevich fe8063e1a0 Revert "[cuda][hip] Add CUDA builtin surface/texture reference support."
This reverts commit 6a9ad5f3f4.
The patch breaks CUDA copmilation.

Differential Revision: https://reviews.llvm.org/D76365
2020-03-27 10:01:38 -07:00
Johannes Doerfert befb4be3a8 [OpenMP] `omp begin/end declare variant` - part 2, sema ("+CG")
This is the second part loosely extracted from D71179 and cleaned up.

This patch provides semantic analysis support for `omp begin/end declare
variant`, mostly as defined in OpenMP technical report 8 (TR8) [0].
The sema handling makes code generation obsolete as we generate "the
right" calls that can just be handled as usual. This handling also
applies to the existing, albeit problematic, `omp declare variant
support`. As a consequence a lot of unneeded code generation and
complexity is removed.

A major purpose of this patch is to provide proper `math.h`/`cmath`
support for OpenMP target offloading. See PR42061, PR42798, PR42799. The
current code was developed with this feature in mind, see [1].

The logic is as follows:

If we have seen a `#pragma omp begin declare variant match(<SELECTOR>)`
but not the corresponding `end declare variant`, and we find a function
definition we will:
  1) Create a function declaration for the definition we were about to generate.
  2) Create a function definition but with a mangled name (according to
     `<SELECTOR>`).
  3) Annotate the declaration with the `OMPDeclareVariantAttr`, the same
     one used already for `omp declare variant`, using and the mangled
     function definition as specialization for the context defined by
     `<SELECTOR>`.

When a call is created we inspect it. If the target has an
`OMPDeclareVariantAttr` attribute we try to specialize the call. To this
end, all variants are checked, the best applicable one is picked and a
new call to the specialization is created. The new call is used instead
of the original one to the base function. To keep the AST printing and
tooling possible we utilize the PseudoObjectExpr. The original call is
the syntactic expression, the specialized call is the semantic
expression.

[0] https://www.openmp.org/wp-content/uploads/openmp-TR8.pdf
[1] https://reviews.llvm.org/D61399#change-496lQkg0mhRN

Reviewers: kiranchandramohan, ABataev, RaviNarayanaswamy, gtbercea, grokos, sdmitriev, JonChesterfield, hfinkel, fghanim, aaron.ballman

Subscribers: bollu, guansong, openmp-commits, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D75779
2020-03-27 02:30:58 -05:00
Michael Liao 6a9ad5f3f4 [cuda][hip] Add CUDA builtin surface/texture reference support.
Summary:
- Even though the bindless surface/texture interfaces are promoted,
  there are still code using surface/texture references. For example,
  [PR#26400](https://bugs.llvm.org/show_bug.cgi?id=26400) reports the
  compilation issue for code using `tex2D` with texture references. For
  better compatibility, this patch proposes the support of
  surface/texture references.
- Due to the absent documentation and magic headers, it's believed that
  `nvcc` does use builtins for texture support. From the limited NVVM
  documentation[^nvvm] and NVPTX backend texture/surface related
  tests[^test], it's believed that surface/texture references are
  supported by replacing their reference types, which are annotated with
  `device_builtin_surface_type`/`device_builtin_texture_type`, with the
  corresponding handle-like object types, `cudaSurfaceObject_t` or
  `cudaTextureObject_t`, in the device-side compilation. On the host
  side, that global handle variables are registered and will be
  established and updated later when corresponding binding/unbinding
  APIs are called[^bind]. Surface/texture references are most like
  device global variables but represented in different types on the host
  and device sides.
- In this patch, the following changes are proposed to support that
  behavior:
  + Refine `device_builtin_surface_type` and
    `device_builtin_texture_type` attributes to be applied on `Type`
    decl only to check whether a variable is of the surface/texture
    reference type.
  + Add hooks in code generation to replace that reference types with
    the correponding object types as well as all accesses to them. In
    particular, `nvvm.texsurf.handle.internal` should be used to load
    object handles from global reference variables[^texsurf] as well as
    metadata annotations.
  + Generate host-side registration with proper template argument
    parsing.

---
[^nvvm]: https://docs.nvidia.com/cuda/pdf/NVVM_IR_Specification.pdf
[^test]: https://raw.githubusercontent.com/llvm/llvm-project/master/llvm/test/CodeGen/NVPTX/tex-read-cuda.ll
[^bind]: See section 3.2.11.1.2 ``Texture reference API` in [CUDA C Programming Guide](https://docs.nvidia.com/cuda/pdf/CUDA_C_Programming_Guide.pdf).
[^texsurf]: According to NVVM IR, `nvvm.texsurf.handle` should be used.  But, the current backend doesn't have that supported. We may revise that later.

Reviewers: tra, rjmccall, yaxunl, a.sidorin

Subscribers: cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D76365
2020-03-26 14:44:52 -04:00
Shiva Chen fc3752665f [RISCV] Passing small data limitation value to RISCV backend
Passing small data limit to RISCVELFTargetObjectFile by module flag,
So the backend can set small data section threshold by the value.
The data will be put into the small data section if the data smaller than
the threshold.

Differential Revision: https://reviews.llvm.org/D57497
2020-03-20 11:03:51 +08:00
Michael Liao 4cf01ed75e [hip] Revise `GlobalDecl` constructors. NFC.
Summary:
- https://reviews.llvm.org/D68578 revises the `GlobalDecl` constructors
  to ensure all GPU kernels have `ReferenceKenelKind` initialized
  properly with an explicit constructor and static one. But, there are
  lots of places using the implicit constructor triggering the assertion
  on non-GPU kernels. That's found in compilation of many tests and
  workloads.
- Fixing all of them may change more code and, more importantly, all of
  them assumes the default kernel reference kind. This patch changes
  that constructor to tell `CUDAGlobalAttr` and construct `GlobalDecl`
  properly.

Reviewers: yaxunl

Subscribers: cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D76344
2020-03-18 09:33:39 -04:00
Jon Chesterfield c45eaeabb7 [Clang] Undef attribute for global variables
Summary:
[Clang] Attribute to allow defining undef global variables

Initializing global variables is very cheap on hosted implementations. The
C semantics of zero initializing globals work very well there. It is not
necessarily cheap on freestanding implementations. Where there is no loader
available, code must be emitted near the start point to write the appropriate
values into memory.

At present, external variables can be declared in C++ and definitions provided
in assembly (or IR) to achive this effect. This patch provides an attribute in
order to remove this reason for writing assembly for performance sensitive
freestanding implementations.

A close analogue in tree is LDS memory for amdgcn, where the kernel is
responsible for initializing the memory after it starts executing on the gpu.
Uninitalized variables in LDS are observably cheaper than zero initialized.

Patch is loosely based on the cuda __shared__ and opencl __local variable
implementation which also produces undef global variables.

Reviewers: kcc, rjmccall, rsmith, glider, vitalybuka, pcc, eugenis, vlad.tsyrklevich, jdoerfert, gregrodgers, jfb, aaron.ballman

Reviewed By: rjmccall, aaron.ballman

Subscribers: Anastasia, aaron.ballman, davidb, Quuxplusone, dexonsmith, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D74361
2020-03-17 21:22:23 +00:00
Reid Kleckner e08464fb45 Avoid including FileManager.h from SourceManager.h
Most clients of SourceManager.h need to do things like turning source
locations into file & line number pairs, but this doesn't require
bringing in FileManager.h and LLVM's FS headers.

The main code change here is to sink SM::createFileID into the cpp file.
I reason that this is not performance critical because it doesn't happen
on the diagnostic path, it happens along the paths of macro expansion
(could be hot) and new includes (less hot).

Saves some includes:
    309 -    /usr/local/google/home/rnk/llvm-project/clang/include/clang/Basic/FileManager.h
    272 -    /usr/local/google/home/rnk/llvm-project/clang/include/clang/Basic/FileSystemOptions.h
    271 -    /usr/local/google/home/rnk/llvm-project/llvm/include/llvm/Support/VirtualFileSystem.h
    267 -    /usr/local/google/home/rnk/llvm-project/llvm/include/llvm/Support/FileSystem.h
    266 -    /usr/local/google/home/rnk/llvm-project/llvm/include/llvm/Support/Chrono.h

Differential Revision: https://reviews.llvm.org/D75406
2020-03-11 13:53:12 -07:00
Yaxun (Sam) Liu 22c457a869 [HIP] Fix device stub name
HIP emits a device stub function for each kernel in host code.

The HIP debugger requires device stub function to have a different unmangled name as the kernel.

Currently the name of the device stub function is the mangled name with a postfix .stub. However,
this does not work with the HIP debugger since the unmangled name is the same as the kernel.

This patch adds prefix __device__stub__ to the unmangled name of the device stub before mangling,
therefore the device stub function has a valid mangled name which is different than the device kernel
name. The device side kernel name is kept unchanged. kernels with extern "C" also gets the prefix added
to the corresponding device stub function.

Differential Revision: https://reviews.llvm.org/D68578
2020-03-09 16:40:05 -04:00
Erich Keane 7b66160828 Fix Target Multiversioning renaming.
The initial implementation only did 'first declaration renaming' when
a default version came after. This is insufficient in cases where a
default does not exist, so this patch makes sure that we do the renaming
in all cases.

This renaming is necessary because we emit the first declaration before
knowing that it IS a target multiversion function, which would change
its name. The second declaration (the one that caused the
multiversioning) then needs to make sure that the first one has its name
changed to be consistent with the resolver usage.
2020-03-09 08:29:18 -07:00