[cfe-commits] r105447 - /cfe/trunk/lib/CodeGen/CGVTables.cpp
Anders Carlsson
andersca at mac.com
Thu Jun 3 17:54:04 PDT 2010
Author: andersca
Date: Thu Jun 3 19:54:04 2010
New Revision: 105447
URL: http://llvm.org/viewvc/llvm-project?rev=105447&view=rev
Log:
Use CXXRecordDecl::getFinalOverriders to get final overriders. This speeds up vtable layout by moving away from the old final overrider computation code that had O(N^2) complexity in some cases.
Modified:
cfe/trunk/lib/CodeGen/CGVTables.cpp
Modified: cfe/trunk/lib/CodeGen/CGVTables.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGVTables.cpp?rev=105447&r1=105446&r2=105447&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGVTables.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGVTables.cpp Thu Jun 3 19:54:04 2010
@@ -150,6 +150,22 @@
static void MergeSubobjectOffsets(const SubobjectOffsetsMapTy &NewOffsets,
SubobjectOffsetsMapTy &Offsets);
+ /// SubobjectsToOffsetsMapTy - A mapping from a base subobject (represented
+ /// as a record decl and a subobject number) and its offsets in the most
+ /// derived class as well as the layout class.
+ typedef llvm::DenseMap<std::pair<const CXXRecordDecl *, unsigned>,
+ uint64_t> SubobjectOffsetMapTy;
+
+ typedef llvm::DenseMap<const CXXRecordDecl *, unsigned> SubobjectCountMapTy;
+
+ /// ComputeBaseOffsets - Compute the offsets for all base subobjects of the
+ /// given base.
+ void ComputeBaseOffsets(BaseSubobject Base, bool IsVirtual,
+ uint64_t OffsetInLayoutClass,
+ SubobjectOffsetMapTy &SubobjectOffsets,
+ SubobjectOffsetMapTy &SubobjectLayoutClassOffsets,
+ SubobjectCountMapTy &SubobjectCounts);
+
public:
FinalOverriders(const CXXRecordDecl *MostDerivedClass,
uint64_t MostDerivedClassOffset,
@@ -187,13 +203,59 @@
MostDerivedClassOffset(MostDerivedClassOffset), LayoutClass(LayoutClass),
Context(MostDerivedClass->getASTContext()),
MostDerivedClassLayout(Context.getASTRecordLayout(MostDerivedClass)) {
-
+#if 0
// Compute the final overriders.
SubobjectOffsetsMapTy Offsets;
ComputeFinalOverriders(BaseSubobject(MostDerivedClass, 0),
/*BaseSubobjectIsVisitedVBase=*/false,
MostDerivedClassOffset, Offsets);
VisitedVirtualBases.clear();
+#endif
+ // Compute base offsets.
+ SubobjectOffsetMapTy SubobjectOffsets;
+ SubobjectOffsetMapTy SubobjectLayoutClassOffsets;
+ SubobjectCountMapTy SubobjectCounts;
+ ComputeBaseOffsets(BaseSubobject(MostDerivedClass, 0), /*IsVirtual=*/false,
+ MostDerivedClassOffset, SubobjectOffsets,
+ SubobjectLayoutClassOffsets, SubobjectCounts);
+
+ // Get the the final overriders.
+ CXXFinalOverriderMap FinalOverriders;
+ MostDerivedClass->getFinalOverriders(FinalOverriders);
+
+ for (CXXFinalOverriderMap::const_iterator I = FinalOverriders.begin(),
+ E = FinalOverriders.end(); I != E; ++I) {
+ const CXXMethodDecl *MD = I->first;
+ const OverridingMethods& Methods = I->second;
+
+ for (OverridingMethods::const_iterator I = Methods.begin(),
+ E = Methods.end(); I != E; ++I) {
+ unsigned SubobjectNumber = I->first;
+ assert(SubobjectOffsets.count(std::make_pair(MD->getParent(),
+ SubobjectNumber)) &&
+ "Did not find subobject offset!");
+
+ uint64_t BaseOffset = SubobjectOffsets[std::make_pair(MD->getParent(),
+ SubobjectNumber)];
+
+ assert(I->second.size() == 1 && "Final overrider is not unique!");
+ const UniqueVirtualMethod &Method = I->second.front();
+
+ const CXXRecordDecl *OverriderRD = Method.Method->getParent();
+ assert(SubobjectLayoutClassOffsets.count(
+ std::make_pair(OverriderRD, Method.Subobject))
+ && "Did not find subobject offset!");
+ uint64_t OverriderOffset =
+ SubobjectLayoutClassOffsets[std::make_pair(OverriderRD,
+ Method.Subobject)];
+
+ OverriderInfo& Overrider = OverridersMap[std::make_pair(MD, BaseOffset)];
+ assert(!Overrider.Method && "Overrider should not exist yet!");
+
+ Overrider.Offset = OverriderOffset;
+ Overrider.Method = Method.Method;
+ }
+ }
#if DUMP_OVERRIDERS
// And dump them (for now).
@@ -478,6 +540,62 @@
Offsets[RD].insert(Base.getBaseOffset());
}
+void
+FinalOverriders::ComputeBaseOffsets(BaseSubobject Base, bool IsVirtual,
+ uint64_t OffsetInLayoutClass,
+ SubobjectOffsetMapTy &SubobjectOffsets,
+ SubobjectOffsetMapTy &SubobjectLayoutClassOffsets,
+ SubobjectCountMapTy &SubobjectCounts) {
+ const CXXRecordDecl *RD = Base.getBase();
+
+ unsigned SubobjectNumber = 0;
+ if (!IsVirtual)
+ SubobjectNumber = ++SubobjectCounts[RD];
+
+ // Set up the subobject to offset mapping.
+ assert(!SubobjectOffsets.count(std::make_pair(RD, SubobjectNumber))
+ && "Subobject offset already exists!");
+ assert(!SubobjectLayoutClassOffsets.count(std::make_pair(RD, SubobjectNumber))
+ && "Subobject offset already exists!");
+
+ SubobjectOffsets[std::make_pair(RD, SubobjectNumber)] =
+ Base.getBaseOffset();
+ SubobjectLayoutClassOffsets[std::make_pair(RD, SubobjectNumber)] =
+ OffsetInLayoutClass;
+
+ // Traverse our bases.
+ for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
+ E = RD->bases_end(); I != E; ++I) {
+ const CXXRecordDecl *BaseDecl =
+ cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
+
+ uint64_t BaseOffset;
+ uint64_t BaseOffsetInLayoutClass;
+ if (I->isVirtual()) {
+ // Check if we've visited this virtual base before.
+ if (SubobjectOffsets.count(std::make_pair(BaseDecl, 0)))
+ continue;
+
+ const ASTRecordLayout &LayoutClassLayout =
+ Context.getASTRecordLayout(LayoutClass);
+
+ BaseOffset = MostDerivedClassLayout.getVBaseClassOffset(BaseDecl);
+ BaseOffsetInLayoutClass =
+ LayoutClassLayout.getVBaseClassOffset(BaseDecl);
+ } else {
+ const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
+ uint64_t Offset = Layout.getBaseClassOffset(BaseDecl);
+
+ BaseOffset = Base.getBaseOffset() + Offset;
+ BaseOffsetInLayoutClass = OffsetInLayoutClass + Offset;
+ }
+
+ ComputeBaseOffsets(BaseSubobject(BaseDecl, BaseOffset), I->isVirtual(),
+ BaseOffsetInLayoutClass, SubobjectOffsets,
+ SubobjectLayoutClassOffsets, SubobjectCounts);
+ }
+}
+
void FinalOverriders::dump(llvm::raw_ostream &Out, BaseSubobject Base) {
const CXXRecordDecl *RD = Base.getBase();
const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
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