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devel/llvm60/files/clang/patch-head-r338697.diff
- This file was added.
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| fbsd:nokeywords | null | yes \ No newline at end of property |
| svn:eol-style | null | native \ No newline at end of property |
| svn:mime-type | null | text/plain \ No newline at end of property |
| r338697 | dim | 2018-09-15 23:22:50 +0200 (Sat, 15 Sep 2018) | 21 lines | |||||
| Pull in r325478 from upstream clang trunk (by Ivan A. Kosarev): | |||||
| [CodeGen] Initialize large arrays by copying from a global | |||||
| Currently, clang compiles explicit initializers for array elements | |||||
| into series of store instructions. For large arrays of built-in types | |||||
| this results in bloated output code and significant amount of time | |||||
| spent on the instruction selection phase. This patch fixes the issue | |||||
| by initializing such arrays with global constants that store the | |||||
| binary image of the initializer. | |||||
| Differential Revision: https://reviews.llvm.org/D43181 | |||||
| This should fix a compiler hang (and excessive memory usage) while | |||||
| building the science/rmg port. | |||||
| Approved by: re (kib) | |||||
| Reported by: yuri@tsoft.com | |||||
| See also: https://bugs.llvm.org/show_bug.cgi?id=38798 | |||||
| MFC after: 3 days | |||||
| Index: tools/clang/lib/CodeGen/CGExprAgg.cpp | |||||
| =================================================================== | |||||
| --- tools/clang/lib/CodeGen/CGExprAgg.cpp (revision 338696) | |||||
| +++ tools/clang/lib/CodeGen/CGExprAgg.cpp (revision 338697) | |||||
| @@ -14,6 +14,7 @@ | |||||
| #include "CodeGenFunction.h" | |||||
| #include "CGObjCRuntime.h" | |||||
| #include "CodeGenModule.h" | |||||
| +#include "ConstantEmitter.h" | |||||
| #include "clang/AST/ASTContext.h" | |||||
| #include "clang/AST/DeclCXX.h" | |||||
| #include "clang/AST/DeclTemplate.h" | |||||
| @@ -85,7 +86,7 @@ class AggExprEmitter : public StmtVisitor<AggExprE | |||||
| void EmitMoveFromReturnSlot(const Expr *E, RValue Src); | |||||
| void EmitArrayInit(Address DestPtr, llvm::ArrayType *AType, | |||||
| - QualType elementType, InitListExpr *E); | |||||
| + QualType ArrayQTy, InitListExpr *E); | |||||
| AggValueSlot::NeedsGCBarriers_t needsGC(QualType T) { | |||||
| if (CGF.getLangOpts().getGC() && TypeRequiresGCollection(T)) | |||||
| @@ -392,12 +393,15 @@ static bool isTrivialFiller(Expr *E) { | |||||
| /// \brief Emit initialization of an array from an initializer list. | |||||
| void AggExprEmitter::EmitArrayInit(Address DestPtr, llvm::ArrayType *AType, | |||||
| - QualType elementType, InitListExpr *E) { | |||||
| + QualType ArrayQTy, InitListExpr *E) { | |||||
| uint64_t NumInitElements = E->getNumInits(); | |||||
| uint64_t NumArrayElements = AType->getNumElements(); | |||||
| assert(NumInitElements <= NumArrayElements); | |||||
| + QualType elementType = | |||||
| + CGF.getContext().getAsArrayType(ArrayQTy)->getElementType(); | |||||
| + | |||||
| // DestPtr is an array*. Construct an elementType* by drilling | |||||
| // down a level. | |||||
| llvm::Value *zero = llvm::ConstantInt::get(CGF.SizeTy, 0); | |||||
| @@ -409,6 +413,29 @@ void AggExprEmitter::EmitArrayInit(Address DestPtr | |||||
| CharUnits elementAlign = | |||||
| DestPtr.getAlignment().alignmentOfArrayElement(elementSize); | |||||
| + // Consider initializing the array by copying from a global. For this to be | |||||
| + // more efficient than per-element initialization, the size of the elements | |||||
| + // with explicit initializers should be large enough. | |||||
| + if (NumInitElements * elementSize.getQuantity() > 16 && | |||||
| + elementType.isTriviallyCopyableType(CGF.getContext())) { | |||||
| + CodeGen::CodeGenModule &CGM = CGF.CGM; | |||||
| + ConstantEmitter Emitter(CGM); | |||||
| + LangAS AS = ArrayQTy.getAddressSpace(); | |||||
| + if (llvm::Constant *C = Emitter.tryEmitForInitializer(E, AS, ArrayQTy)) { | |||||
| + auto GV = new llvm::GlobalVariable( | |||||
| + CGM.getModule(), C->getType(), | |||||
| + CGM.isTypeConstant(ArrayQTy, /* ExcludeCtorDtor= */ true), | |||||
| + llvm::GlobalValue::PrivateLinkage, C, "constinit", | |||||
| + /* InsertBefore= */ nullptr, llvm::GlobalVariable::NotThreadLocal, | |||||
| + CGM.getContext().getTargetAddressSpace(AS)); | |||||
| + Emitter.finalize(GV); | |||||
| + CharUnits Align = CGM.getContext().getTypeAlignInChars(ArrayQTy); | |||||
| + GV->setAlignment(Align.getQuantity()); | |||||
| + EmitFinalDestCopy(ArrayQTy, CGF.MakeAddrLValue(GV, ArrayQTy, Align)); | |||||
| + return; | |||||
| + } | |||||
| + } | |||||
| + | |||||
| // Exception safety requires us to destroy all the | |||||
| // already-constructed members if an initializer throws. | |||||
| // For that, we'll need an EH cleanup. | |||||
| @@ -1156,11 +1183,8 @@ void AggExprEmitter::VisitInitListExpr(InitListExp | |||||
| // Handle initialization of an array. | |||||
| if (E->getType()->isArrayType()) { | |||||
| - QualType elementType = | |||||
| - CGF.getContext().getAsArrayType(E->getType())->getElementType(); | |||||
| - | |||||
| auto AType = cast<llvm::ArrayType>(Dest.getAddress().getElementType()); | |||||
| - EmitArrayInit(Dest.getAddress(), AType, elementType, E); | |||||
| + EmitArrayInit(Dest.getAddress(), AType, E->getType(), E); | |||||
| return; | |||||
| } | |||||