Fix some DenseMap use-after-rehash bugs and hoist MethodVFTableLocation
This re-lands r328845 with fixes for crbug.com/827810.
The initial motiviation was to hoist MethodVFTableLocation to global
scope so it could be forward declared.
In this patch, I noticed that MicrosoftVTableContext uses some risky
patterns. It has methods that return references to data stored in
DenseMaps. I've made some of them return by value for trivial structs
and I've moved some things into separate allocations.
llvm-svn: 329007
diff --git a/clang/lib/CodeGen/MicrosoftCXXABI.cpp b/clang/lib/CodeGen/MicrosoftCXXABI.cpp
index 542e1bf..d5b168d 100644
--- a/clang/lib/CodeGen/MicrosoftCXXABI.cpp
+++ b/clang/lib/CodeGen/MicrosoftCXXABI.cpp
@@ -230,7 +230,7 @@
getThisArgumentTypeForMethod(const CXXMethodDecl *MD) override {
MD = MD->getCanonicalDecl();
if (MD->isVirtual() && !isa<CXXDestructorDecl>(MD)) {
- MicrosoftVTableContext::MethodVFTableLocation ML =
+ MethodVFTableLocation ML =
CGM.getMicrosoftVTableContext().getMethodVFTableLocation(MD);
// The vbases might be ordered differently in the final overrider object
// and the complete object, so the "this" argument may sometimes point to
@@ -616,9 +616,8 @@
const VBTableGlobals &enumerateVBTables(const CXXRecordDecl *RD);
/// \brief Generate a thunk for calling a virtual member function MD.
- llvm::Function *EmitVirtualMemPtrThunk(
- const CXXMethodDecl *MD,
- const MicrosoftVTableContext::MethodVFTableLocation &ML);
+ llvm::Function *EmitVirtualMemPtrThunk(const CXXMethodDecl *MD,
+ const MethodVFTableLocation &ML);
public:
llvm::Type *ConvertMemberPointerType(const MemberPointerType *MPT) override;
@@ -1336,7 +1335,7 @@
LookupGD = GlobalDecl(DD, Dtor_Deleting);
}
- MicrosoftVTableContext::MethodVFTableLocation ML =
+ MethodVFTableLocation ML =
CGM.getMicrosoftVTableContext().getMethodVFTableLocation(LookupGD);
CharUnits Adjustment = ML.VFPtrOffset;
@@ -1385,7 +1384,7 @@
// with the base one, so look up the deleting one instead.
LookupGD = GlobalDecl(DD, Dtor_Deleting);
}
- MicrosoftVTableContext::MethodVFTableLocation ML =
+ MethodVFTableLocation ML =
CGM.getMicrosoftVTableContext().getMethodVFTableLocation(LookupGD);
CharUnits StaticOffset = ML.VFPtrOffset;
@@ -1851,8 +1850,7 @@
llvm::Value *VTable = CGF.GetVTablePtr(VPtr, Ty, MethodDecl->getParent());
MicrosoftVTableContext &VFTContext = CGM.getMicrosoftVTableContext();
- MicrosoftVTableContext::MethodVFTableLocation ML =
- VFTContext.getMethodVFTableLocation(GD);
+ MethodVFTableLocation ML = VFTContext.getMethodVFTableLocation(GD);
// Compute the identity of the most derived class whose virtual table is
// located at the MethodVFTableLocation ML.
@@ -1937,16 +1935,16 @@
return VBGlobals;
}
-llvm::Function *MicrosoftCXXABI::EmitVirtualMemPtrThunk(
- const CXXMethodDecl *MD,
- const MicrosoftVTableContext::MethodVFTableLocation &ML) {
+llvm::Function *
+MicrosoftCXXABI::EmitVirtualMemPtrThunk(const CXXMethodDecl *MD,
+ const MethodVFTableLocation &ML) {
assert(!isa<CXXConstructorDecl>(MD) && !isa<CXXDestructorDecl>(MD) &&
"can't form pointers to ctors or virtual dtors");
// Calculate the mangled name.
SmallString<256> ThunkName;
llvm::raw_svector_ostream Out(ThunkName);
- getMangleContext().mangleVirtualMemPtrThunk(MD, Out);
+ getMangleContext().mangleVirtualMemPtrThunk(MD, ML, Out);
// If the thunk has been generated previously, just return it.
if (llvm::GlobalValue *GV = CGM.getModule().getNamedValue(ThunkName))
@@ -2760,8 +2758,7 @@
FirstField = CGM.GetAddrOfFunction(MD, Ty);
} else {
auto &VTableContext = CGM.getMicrosoftVTableContext();
- MicrosoftVTableContext::MethodVFTableLocation ML =
- VTableContext.getMethodVFTableLocation(MD);
+ MethodVFTableLocation ML = VTableContext.getMethodVFTableLocation(MD);
FirstField = EmitVirtualMemPtrThunk(MD, ML);
// Include the vfptr adjustment if the method is in a non-primary vftable.
NonVirtualBaseAdjustment += ML.VFPtrOffset;