From 2177ab7be5256e691a115356fcb8f3eef9c9733f Mon Sep 17 00:00:00 2001 From: Anders Carlsson Date: Tue, 8 Jun 2010 16:20:35 +0000 Subject: [PATCH] When checking whether we can place a base subobject at an offset, we don't need to go past the highest offset that's known to contain an empty base subobject. git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@105611 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/AST/RecordLayoutBuilder.cpp | 23 ++++++++++++++++++++++- 1 file changed, 22 insertions(+), 1 deletion(-) diff --git a/lib/AST/RecordLayoutBuilder.cpp b/lib/AST/RecordLayoutBuilder.cpp index 704a974a88..77b6f8a1c3 100644 --- a/lib/AST/RecordLayoutBuilder.cpp +++ b/lib/AST/RecordLayoutBuilder.cpp @@ -107,7 +107,8 @@ public: uint64_t SizeOfLargestEmptySubobject; EmptySubobjectMap(ASTContext &Context, const CXXRecordDecl *Class) - : Context(Context), Class(Class), SizeOfLargestEmptySubobject(0) { + : Context(Context), Class(Class), MaxEmptyClassOffset(0), + SizeOfLargestEmptySubobject(0) { ComputeEmptySubobjectSizes(); } @@ -210,6 +211,11 @@ void EmptySubobjectMap::AddSubobjectAtOffset(const CXXRecordDecl *RD, bool EmptySubobjectMap::CanPlaceBaseSubobjectAtOffset(const BaseSubobjectInfo *Info, uint64_t Offset) { + // We don't have to keep looking past the maximum offset that's known to + // contain an empty class. + if (!AnyEmptySubobjectsBeyondOffset(Offset)) + return true; + if (!CanPlaceSubobjectAtOffset(Info->Class, Offset)) return false; @@ -302,6 +308,11 @@ bool EmptySubobjectMap::CanPlaceFieldSubobjectAtOffset(const CXXRecordDecl *RD, const CXXRecordDecl *Class, uint64_t Offset) const { + // We don't have to keep looking past the maximum offset that's known to + // contain an empty class. + if (!AnyEmptySubobjectsBeyondOffset(Offset)) + return true; + if (!CanPlaceSubobjectAtOffset(RD, Offset)) return false; @@ -338,6 +349,11 @@ EmptySubobjectMap::CanPlaceFieldSubobjectAtOffset(const CXXRecordDecl *RD, bool EmptySubobjectMap::CanPlaceFieldSubobjectAtOffset(const FieldDecl *FD, uint64_t Offset) const { + // We don't have to keep looking past the maximum offset that's known to + // contain an empty class. + if (!AnyEmptySubobjectsBeyondOffset(Offset)) + return true; + QualType T = FD->getType(); if (const RecordType *RT = T->getAs()) { const CXXRecordDecl *RD = cast(RT->getDecl()); @@ -357,6 +373,11 @@ bool EmptySubobjectMap::CanPlaceFieldSubobjectAtOffset(const FieldDecl *FD, uint64_t NumElements = Context.getConstantArrayElementCount(AT); uint64_t ElementOffset = Offset; for (uint64_t I = 0; I != NumElements; ++I) { + // We don't have to keep looking past the maximum offset that's known to + // contain an empty class. + if (!AnyEmptySubobjectsBeyondOffset(ElementOffset)) + return true; + if (!CanPlaceFieldSubobjectAtOffset(RD, RD, ElementOffset)) return false; -- 2.40.0