Hi David, On Reid's patch for this (D25581), Richard said, "This takes the alignment in bits? That's so ridiculously dumb that I would feel bad about accepting this patch unless it comes with a warning for people writing the obvious-but-wrong __builtin_alloca_with_align(sizeof(T), alignof(T))". We should add the warning.
Thanks again, Hal ----- Original Message ----- > From: "David Majnemer via cfe-commits" <cfe-commits@lists.llvm.org> > To: cfe-commits@lists.llvm.org > Sent: Monday, October 31, 2016 12:37:49 AM > Subject: r285544 - Add support for __builtin_alloca_with_align > > Author: majnemer > Date: Mon Oct 31 00:37:48 2016 > New Revision: 285544 > > URL: http://llvm.org/viewvc/llvm-project?rev=285544&view=rev > Log: > Add support for __builtin_alloca_with_align > > __builtin_alloca always uses __BIGGEST_ALIGNMENT__ for the alignment > of > the allocation. __builtin_alloca_with_align allows the programmer to > specify the alignment of the allocation. > > This fixes PR30658. > > Added: > cfe/trunk/test/Sema/builtin-alloca-with-align.c > Modified: > cfe/trunk/include/clang/Basic/Builtins.def > cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td > cfe/trunk/include/clang/Sema/Sema.h > cfe/trunk/lib/CodeGen/CGBuiltin.cpp > cfe/trunk/lib/Sema/SemaChecking.cpp > cfe/trunk/lib/StaticAnalyzer/Checkers/BuiltinFunctionChecker.cpp > cfe/trunk/lib/StaticAnalyzer/Checkers/UnixAPIChecker.cpp > cfe/trunk/test/CodeGen/builtins-ms.c > > Modified: cfe/trunk/include/clang/Basic/Builtins.def > URL: > http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/Builtins.def?rev=285544&r1=285543&r2=285544&view=diff > ============================================================================== > --- cfe/trunk/include/clang/Basic/Builtins.def (original) > +++ cfe/trunk/include/clang/Basic/Builtins.def Mon Oct 31 00:37:48 > 2016 > @@ -512,6 +512,7 @@ BUILTIN(__builtin_unreachable, "v", "nr" > BUILTIN(__builtin_shufflevector, "v." , "nc") > BUILTIN(__builtin_convertvector, "v." , "nct") > BUILTIN(__builtin_alloca, "v*z" , "Fn") > +BUILTIN(__builtin_alloca_with_align, "v*zIz", "Fn") > BUILTIN(__builtin_call_with_static_chain, "v.", "nt") > > // "Overloaded" Atomic operator builtins. These are overloaded to > support data > > Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td > URL: > http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=285544&r1=285543&r2=285544&view=diff > ============================================================================== > --- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original) > +++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Mon Oct 31 > 00:37:48 2016 > @@ -2440,6 +2440,10 @@ def err_no_accessor_for_property : Error > def error_cannot_find_suitable_accessor : Error< > "cannot find suitable %select{getter|setter}0 for property %1">; > > +def err_alignment_too_small : Error< > + "requested alignment must be %0 or greater">; > +def err_alignment_too_big : Error< > + "requested alignment must be %0 or smaller">; > def err_alignment_not_power_of_two : Error< > "requested alignment is not a power of 2">; > def err_alignment_dependent_typedef_name : Error< > > Modified: cfe/trunk/include/clang/Sema/Sema.h > URL: > http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Sema/Sema.h?rev=285544&r1=285543&r2=285544&view=diff > ============================================================================== > --- cfe/trunk/include/clang/Sema/Sema.h (original) > +++ cfe/trunk/include/clang/Sema/Sema.h Mon Oct 31 00:37:48 2016 > @@ -9719,6 +9719,7 @@ public: > > private: > bool SemaBuiltinPrefetch(CallExpr *TheCall); > + bool SemaBuiltinAllocaWithAlign(CallExpr *TheCall); > bool SemaBuiltinAssume(CallExpr *TheCall); > bool SemaBuiltinAssumeAligned(CallExpr *TheCall); > bool SemaBuiltinLongjmp(CallExpr *TheCall); > > Modified: cfe/trunk/lib/CodeGen/CGBuiltin.cpp > URL: > http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGBuiltin.cpp?rev=285544&r1=285543&r2=285544&view=diff > ============================================================================== > --- cfe/trunk/lib/CodeGen/CGBuiltin.cpp (original) > +++ cfe/trunk/lib/CodeGen/CGBuiltin.cpp Mon Oct 31 00:37:48 2016 > @@ -1147,6 +1147,19 @@ RValue CodeGenFunction::EmitBuiltinExpr( > AI->setAlignment(SuitableAlignmentInBytes); > return RValue::get(AI); > } > + > + case Builtin::BI__builtin_alloca_with_align: { > + Value *Size = EmitScalarExpr(E->getArg(0)); > + Value *AlignmentValue = EmitScalarExpr(E->getArg(1)); > + auto *AlignmentCI = cast<ConstantInt>(AlignmentValue); > + unsigned Alignment = AlignmentCI->getZExtValue(); > + const TargetInfo &TI = getContext().getTargetInfo(); > + unsigned AlignmentInBytes = Alignment / TI.getCharWidth(); > + AllocaInst *AI = Builder.CreateAlloca(Builder.getInt8Ty(), > Size); > + AI->setAlignment(AlignmentInBytes); > + return RValue::get(AI); > + } > + > case Builtin::BIbzero: > case Builtin::BI__builtin_bzero: { > Address Dest = EmitPointerWithAlignment(E->getArg(0)); > > Modified: cfe/trunk/lib/Sema/SemaChecking.cpp > URL: > http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaChecking.cpp?rev=285544&r1=285543&r2=285544&view=diff > ============================================================================== > --- cfe/trunk/lib/Sema/SemaChecking.cpp (original) > +++ cfe/trunk/lib/Sema/SemaChecking.cpp Mon Oct 31 00:37:48 2016 > @@ -791,6 +791,10 @@ Sema::CheckBuiltinFunctionCall(FunctionD > if (SemaBuiltinPrefetch(TheCall)) > return ExprError(); > break; > + case Builtin::BI__builtin_alloca_with_align: > + if (SemaBuiltinAllocaWithAlign(TheCall)) > + return ExprError(); > + break; > case Builtin::BI__assume: > case Builtin::BI__builtin_assume: > if (SemaBuiltinAssume(TheCall)) > @@ -3902,6 +3906,36 @@ bool Sema::SemaBuiltinAssume(CallExpr *T > > return false; > } > + > +/// Handle __builtin_assume_aligned. This is declared > +/// as (size_t, size_t) where the second size_t must be a power of 2 > greater > +/// than 8. > +bool Sema::SemaBuiltinAllocaWithAlign(CallExpr *TheCall) { > + // The alignment must be a constant integer. > + Expr *Arg = TheCall->getArg(1); > + > + // We can't check the value of a dependent argument. > + if (!Arg->isTypeDependent() && !Arg->isValueDependent()) { > + llvm::APSInt Result = Arg->EvaluateKnownConstInt(Context); > + > + if (!Result.isPowerOf2()) > + return Diag(TheCall->getLocStart(), > + diag::err_alignment_not_power_of_two) > + << Arg->getSourceRange(); > + > + if (Result < Context.getCharWidth()) > + return Diag(TheCall->getLocStart(), > diag::err_alignment_too_small) > + << (unsigned)Context.getCharWidth() > + << Arg->getSourceRange(); > + > + if (Result > INT32_MAX) > + return Diag(TheCall->getLocStart(), > diag::err_alignment_too_big) > + << INT32_MAX > + << Arg->getSourceRange(); > + } > + > + return false; > +} > > /// Handle __builtin_assume_aligned. This is declared > /// as (const void*, size_t, ...) and can take one optional constant > int arg. > > Modified: > cfe/trunk/lib/StaticAnalyzer/Checkers/BuiltinFunctionChecker.cpp > URL: > http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/StaticAnalyzer/Checkers/BuiltinFunctionChecker.cpp?rev=285544&r1=285543&r2=285544&view=diff > ============================================================================== > --- cfe/trunk/lib/StaticAnalyzer/Checkers/BuiltinFunctionChecker.cpp > (original) > +++ cfe/trunk/lib/StaticAnalyzer/Checkers/BuiltinFunctionChecker.cpp > Mon Oct 31 00:37:48 2016 > @@ -55,6 +55,7 @@ bool BuiltinFunctionChecker::evalCall(co > return true; > } > > + case Builtin::BI__builtin_alloca_with_align: > case Builtin::BI__builtin_alloca: { > // FIXME: Refactor into StoreManager itself? > MemRegionManager& RM = C.getStoreManager().getRegionManager(); > > Modified: cfe/trunk/lib/StaticAnalyzer/Checkers/UnixAPIChecker.cpp > URL: > http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/StaticAnalyzer/Checkers/UnixAPIChecker.cpp?rev=285544&r1=285543&r2=285544&view=diff > ============================================================================== > --- cfe/trunk/lib/StaticAnalyzer/Checkers/UnixAPIChecker.cpp > (original) > +++ cfe/trunk/lib/StaticAnalyzer/Checkers/UnixAPIChecker.cpp Mon Oct > 31 00:37:48 2016 > @@ -43,6 +43,7 @@ public: > void CheckReallocZero(CheckerContext &C, const CallExpr *CE) > const; > void CheckReallocfZero(CheckerContext &C, const CallExpr *CE) > const; > void CheckAllocaZero(CheckerContext &C, const CallExpr *CE) const; > + void CheckAllocaWithAlignZero(CheckerContext &C, const CallExpr > *CE) const; > void CheckVallocZero(CheckerContext &C, const CallExpr *CE) const; > > typedef void (UnixAPIChecker::*SubChecker)(CheckerContext &, > @@ -337,6 +338,11 @@ void UnixAPIChecker::CheckAllocaZero(Che > BasicAllocationCheck(C, CE, 1, 0, "alloca"); > } > > +void UnixAPIChecker::CheckAllocaWithAlignZero(CheckerContext &C, > + const CallExpr *CE) > const { > + BasicAllocationCheck(C, CE, 2, 0, "__builtin_alloca_with_align"); > +} > + > void UnixAPIChecker::CheckVallocZero(CheckerContext &C, > const CallExpr *CE) const { > BasicAllocationCheck(C, CE, 1, 0, "valloc"); > @@ -366,6 +372,8 @@ void UnixAPIChecker::checkPreStmt(const > .Case("realloc", &UnixAPIChecker::CheckReallocZero) > .Case("reallocf", &UnixAPIChecker::CheckReallocfZero) > .Cases("alloca", "__builtin_alloca", > &UnixAPIChecker::CheckAllocaZero) > + .Case("__builtin_alloca_with_align", > + &UnixAPIChecker::CheckAllocaWithAlignZero) > .Case("valloc", &UnixAPIChecker::CheckVallocZero) > .Default(nullptr); > > > Modified: cfe/trunk/test/CodeGen/builtins-ms.c > URL: > http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/builtins-ms.c?rev=285544&r1=285543&r2=285544&view=diff > ============================================================================== > --- cfe/trunk/test/CodeGen/builtins-ms.c (original) > +++ cfe/trunk/test/CodeGen/builtins-ms.c Mon Oct 31 00:37:48 2016 > @@ -1,9 +1,16 @@ > // RUN: %clang_cc1 %s -emit-llvm -o - -fms-extensions -triple > i686-pc-win32 | FileCheck %s > > -// CHECK-LABEL: define void @test_alloca > +// CHECK-LABEL: define void @test_alloca( > void capture(void *); > void test_alloca(int n) { > capture(_alloca(n)); > // CHECK: %[[arg:.*]] = alloca i8, i32 %{{.*}}, align 16 > // CHECK: call void @capture(i8* %[[arg]]) > } > + > +// CHECK-LABEL: define void @test_alloca_with_align( > +void test_alloca_with_align(int n) { > + capture(__builtin_alloca_with_align(n, 64)); > + // CHECK: %[[arg:.*]] = alloca i8, i32 %{{.*}}, align 8 > + // CHECK: call void @capture(i8* %[[arg]]) > +} > > Added: cfe/trunk/test/Sema/builtin-alloca-with-align.c > URL: > http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/builtin-alloca-with-align.c?rev=285544&view=auto > ============================================================================== > --- cfe/trunk/test/Sema/builtin-alloca-with-align.c (added) > +++ cfe/trunk/test/Sema/builtin-alloca-with-align.c Mon Oct 31 > 00:37:48 2016 > @@ -0,0 +1,29 @@ > +// RUN: %clang_cc1 -fsyntax-only -verify %s > + > +void test1(int a) { > + __builtin_alloca_with_align(a, 32); > +} > + > +void test2(int a) { > + __builtin_alloca_with_align(a, -32); // expected-error {{requested > alignment is not a power of 2}} > +} > + > +void test3(unsigned *b) { > + __builtin_alloca_with_align(b, 32); // expected-warning > {{incompatible pointer to integer conversion passing 'unsigned int > *' to parameter of type}} > +} > + > +void test4(int a) { > + __builtin_alloca_with_align(a, 32, 0); // expected-error {{too > many arguments to function call, expected 2, have 3}} > +} > + > +void test5(int a) { > + __builtin_alloca_with_align(a, 31); // expected-error {{requested > alignment is not a power of 2}} > +} > + > +void test6(int a, int j) { > + __builtin_alloca_with_align(a, j); // expected-error {{must be a > constant integer}} > +} > + > +void test7(int a) { > + __builtin_alloca_with_align(a, 2); // expected-error {{requested > alignment must be 8 or greater}} > +} > > > _______________________________________________ > cfe-commits mailing list > cfe-commits@lists.llvm.org > http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits > -- Hal Finkel Lead, Compiler Technology and Programming Languages Leadership Computing Facility Argonne National Laboratory _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
