commit cbec0269baeaa572bcfb62fdac7dea708d94c1e9
author Reid Kleckner <rnk@google.com> Mon Apr 02 20:00:39 2018 +0000
committer Reid Kleckner <rnk@google.com> Mon Apr 02 20:00:39 2018 +0000
tree 98af7e672bbecd6da6c94975f3269620ca3f9090
parent 227d4399bf32dc87a8307af6f1c86cd5bdde5e08

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

clang/lib/AST/MicrosoftMangle.cpp

diff --git a/clang/lib/AST/MicrosoftMangle.cpp b/clang/lib/AST/MicrosoftMangle.cpp
index 785ee3a..9d49e0f 100644
--- a/clang/lib/AST/MicrosoftMangle.cpp
+++ b/clang/lib/AST/MicrosoftMangle.cpp
@@ -135,7 +135,8 @@
   bool shouldMangleStringLiteral(const StringLiteral *SL) override;
   void mangleCXXName(const NamedDecl *D, raw_ostream &Out) override;
   void mangleVirtualMemPtrThunk(const CXXMethodDecl *MD,
-                                raw_ostream &) override;
+                                const MethodVFTableLocation &ML,
+                                raw_ostream &Out) override;
   void mangleThunk(const CXXMethodDecl *MD, const ThunkInfo &Thunk,
                    raw_ostream &) override;
   void mangleCXXDtorThunk(const CXXDestructorDecl *DD, CXXDtorType Type,
@@ -297,9 +298,8 @@
   void mangleMemberDataPointer(const CXXRecordDecl *RD, const ValueDecl *VD);
   void mangleMemberFunctionPointer(const CXXRecordDecl *RD,
                                    const CXXMethodDecl *MD);
-  void mangleVirtualMemPtrThunk(
-      const CXXMethodDecl *MD,
-      const MicrosoftVTableContext::MethodVFTableLocation &ML);
+  void mangleVirtualMemPtrThunk(const CXXMethodDecl *MD,
+                                const MethodVFTableLocation &ML);
   void mangleNumber(int64_t Number);
   void mangleTagTypeKind(TagTypeKind TK);
   void mangleArtificalTagType(TagTypeKind TK, StringRef UnqualifiedName,
@@ -607,7 +607,7 @@
     if (MD->isVirtual()) {
       MicrosoftVTableContext *VTContext =
           cast<MicrosoftVTableContext>(getASTContext().getVTableContext());
-      const MicrosoftVTableContext::MethodVFTableLocation &ML =
+      MethodVFTableLocation ML =
           VTContext->getMethodVFTableLocation(GlobalDecl(MD));
       mangleVirtualMemPtrThunk(MD, ML);
       NVOffset = ML.VFPtrOffset.getQuantity();
@@ -644,8 +644,7 @@
 }
 
 void MicrosoftCXXNameMangler::mangleVirtualMemPtrThunk(
-    const CXXMethodDecl *MD,
-    const MicrosoftVTableContext::MethodVFTableLocation &ML) {
+    const CXXMethodDecl *MD, const MethodVFTableLocation &ML) {
   // Get the vftable offset.
   CharUnits PointerWidth = getASTContext().toCharUnitsFromBits(
       getASTContext().getTargetInfo().getPointerWidth(0));
@@ -2775,14 +2774,9 @@
   }
 }
 
-void
-MicrosoftMangleContextImpl::mangleVirtualMemPtrThunk(const CXXMethodDecl *MD,
-                                                     raw_ostream &Out) {
-  MicrosoftVTableContext *VTContext =
-      cast<MicrosoftVTableContext>(getASTContext().getVTableContext());
-  const MicrosoftVTableContext::MethodVFTableLocation &ML =
-      VTContext->getMethodVFTableLocation(GlobalDecl(MD));
-
+void MicrosoftMangleContextImpl::mangleVirtualMemPtrThunk(
+    const CXXMethodDecl *MD, const MethodVFTableLocation &ML,
+    raw_ostream &Out) {
   msvc_hashing_ostream MHO(Out);
   MicrosoftCXXNameMangler Mangler(*this, MHO);
   Mangler.getStream() << '?';