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2017-06-23[ubsan] Improve diagnostics for return value checks (clang)Vedant Kumar1-3/+14
This patch makes ubsan's nonnull return value diagnostics more precise, which makes the diagnostics more useful when there are multiple return statements in a function. Example: 1 |__attribute__((returns_nonnull)) char *foo() { 2 | if (...) { 3 | return expr_which_might_evaluate_to_null(); 4 | } else { 5 | return another_expr_which_might_evaluate_to_null(); 6 | } 7 |} // <- The current diagnostic always points here! runtime error: Null returned from Line 7, Column 2! With this patch, the diagnostic would point to either Line 3, Column 5 or Line 5, Column 5. This is done by emitting source location metadata for each return statement in a sanitized function. The runtime is passed a pointer to the appropriate metadata so that it can prepare and deduplicate reports. Compiler-rt patch (with more tests): https://reviews.llvm.org/D34298 Differential Revision: https://reviews.llvm.org/D34299 llvm-svn: 306163
2017-06-19CodeGen: Cast temporary variable to proper address spaceYaxun Liu1-8/+34
In C++ all variables are in default address space. Previously change has been made to cast automatic variables to default address space. However that is not sufficient since all temporary variables need to be casted to default address space. This patch casts all temporary variables to default address space except those for passing indirect arguments since they are only used for load/store. This patch only affects target having non-zero alloca address space. Differential Revision: https://reviews.llvm.org/D33706 llvm-svn: 305711
2017-06-15[coroutines] Allow co_await and co_yield expressions that return an lvalue ↵Eric Fiselier1-0/+2
to compile Summary: The title says it all. Reviewers: GorNishanov, rsmith Reviewed By: GorNishanov Subscribers: rjmccall, cfe-commits Differential Revision: https://reviews.llvm.org/D34194 llvm-svn: 305496
2017-06-12[ubsan] Detect invalid unsigned pointer index expression (clang)Vedant Kumar1-0/+2
Adding an unsigned offset to a base pointer has undefined behavior if the result of the expression would precede the base. An example from @regehr: int foo(char *p, unsigned offset) { return p + offset >= p; // This may be optimized to '1'. } foo(p, -1); // UB. This patch extends the pointer overflow check in ubsan to detect invalid unsigned pointer index expressions. It changes the instrumentation to only permit non-negative offsets in pointer index expressions when all of the GEP indices are unsigned. Testing: check-llvm, check-clang run on a stage2, ubsan-instrumented build. Differential Revision: https://reviews.llvm.org/D33910 llvm-svn: 305216
2017-06-01[ubsan] Add a check for pointer overflow UBVedant Kumar1-0/+8
Check pointer arithmetic for overflow. For some more background on this check, see: https://wdtz.org/catching-pointer-overflow-bugs.html https://reviews.llvm.org/D20322 Patch by Will Dietz and John Regehr! This version of the patch is different from the original in a few ways: - It introduces the EmitCheckedInBoundsGEP utility which inserts checks when the pointer overflow check is enabled. - It does some constant-folding to reduce instrumentation overhead. - It does not check some GEPs in CGExprCXX. I'm not sure that inserting checks here, or in CGClass, would catch many bugs. Possible future directions for this check: - Introduce CGF.EmitCheckedStructGEP, to detect overflows when accessing structures. Testing: Apart from the added lit test, I ran check-llvm and check-clang with a stage2, ubsan-instrumented clang. Will and John have also done extensive testing on numerous open source projects. Differential Revision: https://reviews.llvm.org/D33305 llvm-svn: 304459
2017-05-19Restore and update documentation comment for EmitPointerWithAlignmentKrzysztof Parzyszek1-5/+16
llvm-svn: 303419
2017-05-19CodeGenFunction::EmitPointerWithAlignment(): Prune a \param in r303358, ↵NAKAMURA Takumi1-15/+0
possibly obsolete. [-Wdocumentation] llvm-svn: 303414
2017-05-18[CodeGen] Propagate LValueBaseInfo instead of AlignmentSourceKrzysztof Parzyszek1-14/+17
The functions creating LValues propagated information about alignment source. Extend the propagated data to also include information about possible unrestricted aliasing. A new class LValueBaseInfo will contain both AlignmentSource and MayAlias info. This patch should not introduce any functional changes. Differential Revision: https://reviews.llvm.org/D33284 llvm-svn: 303358
2017-05-04[OpenCL] Add intel_reqd_sub_group_size attribute supportXiuli Pan1-10/+2
Summary: Add intel_reqd_sub_group_size attribute support as intel extension cl_intel_required_subgroup_size from https://www.khronos.org/registry/OpenCL/extensions/intel/cl_intel_required_subgroup_size.txt Reviewers: Anastasia, bader, hfinkel, pxli168 Reviewed By: Anastasia, bader, pxli168 Subscribers: cfe-commits, yaxunl Differential Revision: https://reviews.llvm.org/D30805 llvm-svn: 302125
2017-05-01Adapt to LLVM's rename of WeakVH to WeakTrackingVH; NFCSanjoy Das1-3/+4
llvm-svn: 301815
2017-04-28[CodeGen][ObjC] Don't retain captured Objective-C pointers at blockAkira Hatanaka1-0/+1
creation that are const-qualified. When a block captures an ObjC object pointer, clang retains the pointer to prevent prematurely destroying the object the pointer points to before the block is called or copied. When the captured object pointer is const-qualified, we can avoid emitting the retain/release pair since the pointer variable cannot be modified in the scope in which the block literal is introduced. For example: void test(const id x) { callee(^{ (void)x; }); } This patch implements that optimization. rdar://problem/28894510 Differential Revision: https://reviews.llvm.org/D32601 llvm-svn: 301667
2017-04-26Revert "Update to LLVM's use of WeakTrackingVH; NFC"Sanjoy Das1-4/+3
This reverts commit r301427. llvm-svn: 301430
2017-04-26Update to LLVM's use of WeakTrackingVH; NFCSanjoy Das1-3/+4
Summary: Depends on D32266 Reviewers: davide, dblaikie Subscribers: mcrosier, llvm-commits Differential Revision: https://reviews.llvm.org/D32270 llvm-svn: 301427
2017-04-25Recommit ofCarlo Bertolli1-16/+80
[OpenMP] Initial implementation of code generation for pragma 'distribute parallel for' on host https://reviews.llvm.org/D29508 This patch makes the following additions: It abstracts away loop bound generation code from procedures associated with pragma 'for' and loops in general, in such a way that the same procedures can be used for 'distribute parallel for' without the need for a full re-implementation. It implements code generation for 'distribute parallel for' and adds regression tests. It includes tests for clauses. It is important to notice that most of the clauses are implemented as part of existing procedures. For instance, firstprivate is already implemented for 'distribute' and 'for' as separate pragmas. As the implementation of 'distribute parallel for' is based on the same procedures, then we automatically obtain implementation for such clauses without the need to add new code. However, this requires regression tests that verify correctness of produced code. llvm-svn: 301340
2017-04-24Revert r301223Carlo Bertolli1-80/+16
llvm-svn: 301233
2017-04-24[OpenMP] Initial implementation of code generation for pragma 'distribute ↵Carlo Bertolli1-16/+80
parallel for' on host https://reviews.llvm.org/D29508 This patch makes the following additions: 1. It abstracts away loop bound generation code from procedures associated with pragma 'for' and loops in general, in such a way that the same procedures can be used for 'distribute parallel for' without the need for a full re-implementation. 2. It implements code generation for 'distribute parallel for' and adds regression tests. It includes tests for clauses. It is important to notice that most of the clauses are implemented as part of existing procedures. For instance, firstprivate is already implemented for 'distribute' and 'for' as separate pragmas. As the implementation of 'distribute parallel for' is based on the same procedures, then we automatically obtain implementation for such clauses without the need to add new code. However, this requires regression tests that verify correctness of produced code. Looking forward to comments. llvm-svn: 301223
2017-04-14[ubsan] Reduce alignment checking of C++ object pointersVedant Kumar1-3/+2
This patch teaches ubsan to insert an alignment check for the 'this' pointer at the start of each method/lambda. This allows clang to emit significantly fewer alignment checks overall, because if 'this' is aligned, so are its fields. This is essentially the same thing r295515 does, but for the alignment check instead of the null check. One difference is that we keep the alignment checks on member expressions where the base is a DeclRefExpr. There's an opportunity to diagnose unaligned accesses in this situation (as pointed out by Eli, see PR32630). Testing: check-clang, check-ubsan, and a stage2 ubsan build. Along with the patch from D30285, this roughly halves the amount of alignment checks we emit when compiling X86FastISel.cpp. Here are the numbers from patched/unpatched clangs based on r298160. ------------------------------------------ | Setup | # of alignment checks | ------------------------------------------ | unpatched, -O0 | 24326 | | patched, -O0 | 12717 | (-47.7%) ------------------------------------------ Differential Revision: https://reviews.llvm.org/D30283 llvm-svn: 300370
2017-04-07[cfi] Emit __cfi_check stub in the frontend.Evgeniy Stepanov1-0/+3
Previously __cfi_check was created in LTO optimization pipeline, which means LLD has no way of knowing about the existence of this symbol without rescanning the LTO output object. As a result, LLD fails to export __cfi_check, even when given --export-dynamic-symbol flag. llvm-svn: 299806
2017-03-30Clang changes for alloc_align attribute Erich Keane1-0/+6
GCC has the alloc_align attribute, which is similar to assume_aligned, except the attribute's parameter is the index of the integer parameter that needs aligning to. Differential Revision: https://reviews.llvm.org/D29599 llvm-svn: 299117
2017-03-26[coroutines] Add codegen for await and yield expressionsGor Nishanov1-1/+7
Details: Emit suspend expression which roughly looks like: auto && x = CommonExpr(); if (!x.await_ready()) { llvm_coro_save(); x.await_suspend(...); (*) llvm_coro_suspend(); (**) } x.await_resume(); where the result of the entire expression is the result of x.await_resume() (*) If x.await_suspend return type is bool, it allows to veto a suspend: if (x.await_suspend(...)) llvm_coro_suspend(); (**) llvm_coro_suspend() encodes three possible continuations as a switch instruction: %where-to = call i8 @llvm.coro.suspend(...) switch i8 %where-to, label %coro.ret [ ; jump to epilogue to suspend i8 0, label %yield.ready ; go here when resumed i8 1, label %yield.cleanup ; go here when destroyed ] llvm-svn: 298784
2017-03-14[ubsan] Use the nicer nullability diagnostic handlersVedant Kumar1-1/+5
This is a follow-up to r297700 (Add a nullability sanitizer). It addresses some FIXME's re: using nullability-specific diagnostic handlers from compiler-rt, now that the necessary handlers exist. check-ubsan test updates to follow. llvm-svn: 297750
2017-03-14[ubsan] Add a nullability sanitizerVedant Kumar1-0/+17
Teach UBSan to detect when a value with the _Nonnull type annotation assumes a null value. Call expressions, initializers, assignments, and return statements are all checked. Because _Nonnull does not affect IRGen, the new checks are disabled by default. The new driver flags are: -fsanitize=nullability-arg (_Nonnull violation in call) -fsanitize=nullability-assign (_Nonnull violation in assignment) -fsanitize=nullability-return (_Nonnull violation in return stmt) -fsanitize=nullability (all of the above) This patch builds on top of UBSan's existing support for detecting violations of the nonnull attributes ('nonnull' and 'returns_nonnull'), and relies on the compiler-rt support for those checks. Eventually we will need to update the diagnostic messages in compiler-rt (there are FIXME's for this, which will be addressed in a follow-up). One point of note is that the nullability-return check is only allowed to kick in if all arguments to the function satisfy their nullability preconditions. This makes it necessary to emit some null checks in the function body itself. Testing: check-clang and check-ubsan. I also built some Apple ObjC frameworks with an asserts-enabled compiler, and verified that we get valid reports. Differential Revision: https://reviews.llvm.org/D30762 llvm-svn: 297700
2017-03-09Retry: [ubsan] Detect UB loads from bitfieldsVedant Kumar1-1/+1
It's possible to load out-of-range values from bitfields backed by a boolean or an enum. Check for UB loads from bitfields. This is the motivating example: struct S { BOOL b : 1; // Signed ObjC BOOL. }; S s; s.b = 1; // This is actually stored as -1. if (s.b == 1) // Evaluates to false, -1 != 1. ... Changes since the original commit: - Single-bit bools are a special case (see CGF::EmitFromMemory), and we can't avoid dealing with them when loading from a bitfield. Don't try to insert a check in this case. Differential Revision: https://reviews.llvm.org/D30423 llvm-svn: 297389
2017-03-09Revert "[ubsan] Detect UB loads from bitfields"Vedant Kumar1-1/+1
This reverts commit r297298. It breaks the self-host on this bot: http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-bootstrap/builds/962/steps/build%20clang%2Fubsan/logs/stdio llvm-svn: 297331
2017-03-08[ubsan] Detect UB loads from bitfieldsVedant Kumar1-1/+1
It's possible to load out-of-range values from bitfields backed by a boolean or an enum. Check for UB loads from bitfields. This is the motivating example: struct S { BOOL b : 1; // Signed ObjC BOOL. }; S s; s.b = 1; // This is actually stored as -1. if (s.b == 1) // Evaluates to false, -1 != 1. ... Differential Revision: https://reviews.llvm.org/D30423 llvm-svn: 297298
2017-03-06Don't assume cleanup emission preserves dominance in expr evaluationReid Kleckner1-13/+17
Summary: Because of the existence branches out of GNU statement expressions, it is possible that emitting cleanups for a full expression may cause the new insertion point to not be dominated by the result of the inner expression. Consider this example: struct Foo { Foo(); ~Foo(); int x; }; int g(Foo, int); int f(bool cond) { int n = g(Foo(), ({ if (cond) return 0; 42; })); return n; } Before this change, result of the call to 'g' did not dominate its use in the store to 'n'. The early return exit from the statement expression branches to a shared cleanup block, which ends in a switch between the fallthrough destination (the assignment to 'n') or the function exit block. This change solves the problem by spilling and reloading expression evaluation results when any of the active cleanups have branches. I audited the other call sites of enterFullExpression, and they don't appear to keep and Values live across the site of the cleanup, except in ARC code. I wasn't able to create a test case for ARC that exhibits this problem, though. Reviewers: rjmccall, rsmith Subscribers: cfe-commits Differential Revision: https://reviews.llvm.org/D30590 llvm-svn: 297084
2017-03-06[coroutines] Add co_return statement emissionGor Nishanov1-0/+1
Summary: Added co_return statement emission. Tweaked coro-alloc.cpp test to use co_return to trigger coroutine processing instead of co_await, since this change starts emitting the body of the coroutine and await expression handling has not been upstreamed yet. Reviewers: rsmith, majnemer, EricWF, aaron.ballman Reviewed By: rsmith Subscribers: majnemer, llvm-commits, mehdi_amini Differential Revision: https://reviews.llvm.org/D29979 llvm-svn: 297076
2017-03-06[ubsan] Extend the nonnull arg check to ObjCVedant Kumar1-4/+29
UBSan's nonnull argument check applies when a parameter has the "nonnull" attribute. The check currently works for FunctionDecls, but not for ObjCMethodDecls. This patch extends the check to work for ObjC. Differential Revision: https://reviews.llvm.org/D30599 llvm-svn: 296996
2017-02-27[ubsan] Factor out logic to emit a range check. NFC.Vedant Kumar1-0/+7
This is a readability improvement, but it will also help prep an upcoming patch to detect UB loads from bitfields. llvm-svn: 296374
2017-02-25Retry: [profiling] Fix profile counter increment when emitting selects (PR32019)Vedant Kumar1-3/+4
2nd attempt: the first was in r296231, but it had a use after lifetime bug. Clang has logic to lower certain conditional expressions directly into llvm select instructions. However, it does not emit the correct profile counter increment as it does this: it emits an unconditional increment of the counter for the 'then branch', even if the value selected is from the 'else branch' (this is PR32019). That means, given the following snippet, we would report that "0" is selected twice, and that "1" is never selected: int f1(int x) { return x ? 0 : 1; ^2 ^0 } f1(0); f1(1); Fix the problem by using the instrprof_increment_step intrinsic to do the proper increment. llvm-svn: 296245
2017-02-25Revert "[profiling] Fix profile counter increment when emitting selects ↵Vedant Kumar1-4/+3
(PR32019)" This reverts commit r296231. It causes an assertion failure on 32-bit machines clang: /export/users/atombot/llvm/clang-atom-d525-fedora-rel/llvm/lib/IR/Instructions.cpp:263: void llvm::CallInst::init(llvm::FunctionType*, llvm::Value*, llvm::ArrayRef<llvm::Value*>, llvm::ArrayRef<llvm::OperandBundleDefT<llvm::Value*> >, const llvm::Twine&): Assertion `(i >= FTy->getNumParams() || FTy->getParamType(i) == Args[i]->getType()) && "Calling a function with a bad signature!"' failed. llvm::sys::PrintStackTrace(llvm::raw_ostream&) (/export/users/atombot/llvm/clang-atom-d525-fedora-rel/stage1/./bin/clang+0x1c5fbfa) llvm::sys::RunSignalHandlers() (/export/users/atombot/llvm/clang-atom-d525-fedora-rel/stage1/./bin/clang+0x1c5dc7e) SignalHandler(int) (/export/users/atombot/llvm/clang-atom-d525-fedora-rel/stage1/./bin/clang+0x1c5dde2) __restore_rt (/lib64/libpthread.so.0+0x3f1d00efa0) __GI_raise /home/glibctest/rpmbuild/BUILD/glibc-2.17-c758a686/signal/../nptl/sysdeps/unix/sysv/linux/raise.c:56:0 __GI_abort /home/glibctest/rpmbuild/BUILD/glibc-2.17-c758a686/stdlib/abort.c:92:0 __assert_fail_base /home/glibctest/rpmbuild/BUILD/glibc-2.17-c758a686/assert/assert.c:92:0 (/lib64/libc.so.6+0x3f1c82e622) llvm::CallInst::init(llvm::FunctionType*, llvm::Value*, llvm::ArrayRef<llvm::Value*>, llvm::ArrayRef<llvm::OperandBundleDefT<llvm::Value*> >, llvm::Twine const&) (/export/users/atombot/llvm/clang-atom-d525-fedora-rel/stage1/./bin/clang+0x1804e3a) clang::CodeGen::CodeGenPGO::emitCounterIncrement(clang::CodeGen::CGBuilderTy&, clang::Stmt const*, llvm::Value*) (/export/users/atombot/llvm/clang-atom-d525-fedora-rel/stage1/./bin/clang+0x1ec7891) llvm-svn: 296234
2017-02-25[profiling] Fix profile counter increment when emitting selects (PR32019)Vedant Kumar1-3/+4
Clang has logic to lower certain conditional expressions directly into llvm select instructions. However, it does not emit the correct profile counter increment as it does this: it emits an unconditional increment of the counter for the 'then branch', even if the value selected is from the 'else branch' (this is PR32019). That means, given the following snippet, we would report that "0" is selected twice, and that "1" is never selected: int f1(int x) { return x ? 0 : 1; ^2 ^0 } f1(0); f1(1); Fix the problem by using the instrprof_increment_step intrinsic to do the proper increment. llvm-svn: 296231
2017-02-24[profiling] PR31992: Don't skip interesting non-base constructorsVedant Kumar1-0/+2
Fix the fact that we don't assign profile counters to constructors in classes with virtual bases, or constructors with variadic parameters. Differential Revision: https://reviews.llvm.org/D30131 llvm-svn: 296062
2017-02-23[ObjC][CodeGen] CodeGen support for @available.Erik Pilkington1-0/+2
CodeGens uses of @available into calls to the compiler-rt function __isOSVersionAtLeast. This commit is part of a feature that I proposed here: http://lists.llvm.org/pipermail/cfe-dev/2016-July/049851.html Differential revision: https://reviews.llvm.org/D27827 llvm-svn: 296015
2017-02-23[CodeGen] Don't reemit expressions for pass_object_size params.George Burgess IV1-2/+6
This fixes an assertion failure in cases where we had expression statements that declared variables nested inside of pass_object_size args. Since we were emitting the same ExprStmt twice (once for the arg, once for the @llvm.objectsize call), we were getting issues with redefining locals. This also means that we can be more lax about when we emit @llvm.objectsize for pass_object_size args: since we're reusing the arg's value itself, we don't have to care so much about side-effects. llvm-svn: 295935
2017-02-23Rename a helper function, NFC.Vedant Kumar1-2/+3
llvm-svn: 295918
2017-02-17Retry^2: [ubsan] Reduce null checking of C++ object pointers (PR27581)Vedant Kumar1-0/+3
This patch teaches ubsan to insert exactly one null check for the 'this' pointer per method/lambda. Previously, given a load of a member variable from an instance method ('this->x'), ubsan would insert a null check for 'this', and another null check for '&this->x', before allowing the load to occur. Similarly, given a call to a method from another method bound to the same instance ('this->foo()'), ubsan would a redundant null check for 'this'. There is also a redundant null check in the case where the object pointer is a reference ('Ref.foo()'). This patch teaches ubsan to remove the redundant null checks identified above. Testing: check-clang, check-ubsan, and a stage2 ubsan build. I also compiled X86FastISel.cpp with -fsanitize=null using patched/unpatched clangs based on r293572. Here are the number of null checks emitted: ------------------------------------- | Setup | # of null checks | ------------------------------------- | unpatched, -O0 | 21767 | | patched, -O0 | 10758 | ------------------------------------- Changes since the initial commit: - Don't introduce any unintentional object-size or alignment checks. - Don't rely on IRGen of C labels in the test. Differential Revision: https://reviews.llvm.org/D29530 llvm-svn: 295515
2017-02-17[ubsan] Pass a set of checks to skip to EmitTypeCheck() (NFC)Vedant Kumar1-1/+1
CodeGenFunction::EmitTypeCheck accepts a bool flag which controls whether or not null checks are emitted. Make this a bit more flexible by changing the bool to a SanitizerSet. Needed for an upcoming change which deals with a scenario in which we only want to emit null checks. llvm-svn: 295514
2017-02-17Revert "Retry: [ubsan] Reduce null checking of C++ object pointers (PR27581)"Vedant Kumar1-3/+0
This reverts commit r295401. It breaks the ubsan self-host. It inserts object size checks once per C++ method which fire when the structure is empty. llvm-svn: 295494
2017-02-17Retry: [ubsan] Reduce null checking of C++ object pointers (PR27581)Vedant Kumar1-0/+3
This patch teaches ubsan to insert exactly one null check for the 'this' pointer per method/lambda. Previously, given a load of a member variable from an instance method ('this->x'), ubsan would insert a null check for 'this', and another null check for '&this->x', before allowing the load to occur. Similarly, given a call to a method from another method bound to the same instance ('this->foo()'), ubsan would a redundant null check for 'this'. There is also a redundant null check in the case where the object pointer is a reference ('Ref.foo()'). This patch teaches ubsan to remove the redundant null checks identified above. Testing: check-clang and check-ubsan. I also compiled X86FastISel.cpp with -fsanitize=null using patched/unpatched clangs based on r293572. Here are the number of null checks emitted: ------------------------------------- | Setup | # of null checks | ------------------------------------- | unpatched, -O0 | 21767 | | patched, -O0 | 10758 | ------------------------------------- Changes since the initial commit: don't rely on IRGen of C labels in the test. Differential Revision: https://reviews.llvm.org/D29530 llvm-svn: 295401
2017-02-17Revert "[ubsan] Reduce null checking of C++ object pointers (PR27581)"Vedant Kumar1-3/+0
This reverts commit r295391. It breaks this bot: http://lab.llvm.org:8011/builders/clang-with-thin-lto-ubuntu/builds/1898 I need to not rely on labels in the IR test. llvm-svn: 295396
2017-02-17[ubsan] Reduce null checking of C++ object pointers (PR27581)Vedant Kumar1-0/+3
This patch teaches ubsan to insert exactly one null check for the 'this' pointer per method/lambda. Previously, given a load of a member variable from an instance method ('this->x'), ubsan would insert a null check for 'this', and another null check for '&this->x', before allowing the load to occur. Similarly, given a call to a method from another method bound to the same instance ('this->foo()'), ubsan would a redundant null check for 'this'. There is also a redundant null check in the case where the object pointer is a reference ('Ref.foo()'). This patch teaches ubsan to remove the redundant null checks identified above. Testing: check-clang and check-ubsan. I also compiled X86FastISel.cpp with -fsanitize=null using patched/unpatched clangs based on r293572. Here are the number of null checks emitted: ------------------------------------- | Setup | # of null checks | ------------------------------------- | unpatched, -O0 | 21767 | | patched, -O0 | 10758 | ------------------------------------- Differential Revision: https://reviews.llvm.org/D29530 llvm-svn: 295391
2017-02-16[OpenMP] Parallel reduction on the NVPTX device.Arpith Chacko Jacob1-1/+3
This patch implements codegen for the reduction clause on any parallel construct for elementary data types. An efficient implementation requires hierarchical reduction within a warp and a threadblock. It is complicated by the fact that variables declared in the stack of a CUDA thread cannot be shared with other threads. The patch creates a struct to hold reduction variables and a number of helper functions. The OpenMP runtime on the GPU implements reduction algorithms that uses these helper functions to perform reductions within a team. Variables are shared between CUDA threads using shuffle intrinsics. An implementation of reductions on the NVPTX device is substantially different to that of CPUs. However, this patch is written so that there are minimal changes to the rest of OpenMP codegen. The implemented design allows the compiler and runtime to be decoupled, i.e., the runtime does not need to know of the reduction operation(s), the type of the reduction variable(s), or the number of reductions. The design also allows reuse of host codegen, with appropriate specialization for the NVPTX device. While the patch does introduce a number of abstractions, the expected use case calls for inlining of the GPU OpenMP runtime. After inlining and optimizations in LLVM, these abstractions are unwound and performance of OpenMP reductions is comparable to CUDA-canonical code. Patch by Tian Jin in collaboration with Arpith Jacob Reviewers: ABataev Differential Revision: https://reviews.llvm.org/D29758 llvm-svn: 295333
2017-02-16Revert r295319 while investigating buildbot failure.Arpith Chacko Jacob1-3/+1
llvm-svn: 295323
2017-02-16[OpenMP] Parallel reduction on the NVPTX device.Arpith Chacko Jacob1-1/+3
This patch implements codegen for the reduction clause on any parallel construct for elementary data types. An efficient implementation requires hierarchical reduction within a warp and a threadblock. It is complicated by the fact that variables declared in the stack of a CUDA thread cannot be shared with other threads. The patch creates a struct to hold reduction variables and a number of helper functions. The OpenMP runtime on the GPU implements reduction algorithms that uses these helper functions to perform reductions within a team. Variables are shared between CUDA threads using shuffle intrinsics. An implementation of reductions on the NVPTX device is substantially different to that of CPUs. However, this patch is written so that there are minimal changes to the rest of OpenMP codegen. The implemented design allows the compiler and runtime to be decoupled, i.e., the runtime does not need to know of the reduction operation(s), the type of the reduction variable(s), or the number of reductions. The design also allows reuse of host codegen, with appropriate specialization for the NVPTX device. While the patch does introduce a number of abstractions, the expected use case calls for inlining of the GPU OpenMP runtime. After inlining and optimizations in LLVM, these abstractions are unwound and performance of OpenMP reductions is comparable to CUDA-canonical code. Patch by Tian Jin in collaboration with Arpith Jacob Reviewers: ABataev Differential Revision: https://reviews.llvm.org/D29758 llvm-svn: 295319
2017-01-29[OpenMP][NVPTX][CUDA] Adding support for printf for an NVPTX OpenMP device.Arpith Chacko Jacob1-2/+2
Support for CUDA printf is exploited to support printf for an NVPTX OpenMP device. To reflect the support of both programming models, the file CGCUDABuiltin.cpp has been renamed to CGGPUBuiltin.cpp, and the call EmitCUDADevicePrintfCallExpr has been renamed to EmitGPUDevicePrintfCallExpr. Reviewers: jlebar Differential Revision: https://reviews.llvm.org/D17890 llvm-svn: 293444
2017-01-25[CodeGen] Suppress emission of lifetime markers if a label has been seenAkira Hatanaka1-0/+11
in the current lexical scope. clang currently emits the lifetime.start marker of a variable when the variable comes into scope even though a variable's lifetime starts at the entry of the block with which it is associated, according to the C standard. This normally doesn't cause any problems, but in the rare case where a goto jumps backwards past the variable declaration to an earlier point in the block (see the test case added to lifetime2.c), it can cause mis-compilation. To prevent such mis-compiles, this commit conservatively disables emitting lifetime variables when a label has been seen in the current block. This problem was discussed on cfe-dev here: http://lists.llvm.org/pipermail/cfe-dev/2016-July/050066.html rdar://problem/30153946 Differential Revision: https://reviews.llvm.org/D27680 llvm-svn: 293106
2017-01-25[OpenMP] Codegen support for 'target teams' on the host.Arpith Chacko Jacob1-0/+3
This patch adds support for codegen of 'target teams' on the host. This combined directive has two captured statements, one for the 'teams' region, and the other for the 'parallel'. This target teams region is offloaded using the __tgt_target_teams() call. The patch sets the number of teams as an argument to this call. Reviewers: ABataev Differential Revision: https://reviews.llvm.org/D29084 llvm-svn: 293005
2017-01-25Reverting commit because an NVPTX patch sneaked in. Break up into twoArpith Chacko Jacob1-3/+0
patches. llvm-svn: 293003
2017-01-25[OpenMP] Codegen support for 'target teams' on the host.Arpith Chacko Jacob1-0/+3
This patch adds support for codegen of 'target teams' on the host. This combined directive has two captured statements, one for the 'teams' region, and the other for the 'parallel'. This target teams region is offloaded using the __tgt_target_teams() call. The patch sets the number of teams as an argument to this call. Reviewers: ABataev Differential Revision: https://reviews.llvm.org/D29084 llvm-svn: 293001