Generating assumption loads of vptr after ctor call (fixed)

Generating call assume(icmp %vtable, %global_vtable) after constructor
call for devirtualization purposes.

For more info go to:
http://lists.llvm.org/pipermail/cfe-dev/2015-July/044227.html

Edit:
Fixed version because of PR24479.
After this patch got reverted because of ScalarEvolution bug (D12719)
Merged after John McCall big patch (Added Address).

http://reviews.llvm.org/D11859

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@247199 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 22 insertions, 8 deletions

diff --git a/lib/CodeGen/CGCXXABI.h b/lib/CodeGen/CGCXXABI.h
index 828c9ecfc6..fb878e753f 100644
--- a/lib/CodeGen/CGCXXABI.h
+++ b/lib/CodeGen/CGCXXABI.h
@@ -228,8 +228,10 @@ public:
   virtual void emitThrow(CodeGenFunction &CGF, const CXXThrowExpr *E) = 0;
   virtual llvm::GlobalVariable *getThrowInfo(QualType T) { return nullptr; }
 
-  virtual bool canEmitAvailableExternallyVTable(
-      const CXXRecordDecl *RD) const = 0;
+  /// \brief Determine whether it's possible to emit a vtable for \p RD, even
+  /// though we do not know that the vtable has been marked as used by semantic
+  /// analysis.
+  virtual bool canSpeculativelyEmitVTable(const CXXRecordDecl *RD) const = 0;
 
   virtual void emitBeginCatch(CodeGenFunction &CGF, const CXXCatchStmt *C) = 0;
 
@@ -355,13 +357,25 @@ public:
   virtual void emitVTableDefinitions(CodeGenVTables &CGVT,
                                      const CXXRecordDecl *RD) = 0;
 
+  /// Checks if ABI requires extra virtual offset for vtable field.
+  virtual bool
+  isVirtualOffsetNeededForVTableField(CodeGenFunction &CGF,
+                                      CodeGenFunction::VPtr Vptr) = 0;
+
+  /// Checks if ABI requires to initilize vptrs for given dynamic class.
+  virtual bool doStructorsInitializeVPtrs(const CXXRecordDecl *VTableClass) = 0;
+
+  /// Get the address point of the vtable for the given base subobject.
+  virtual llvm::Constant *
+  getVTableAddressPoint(BaseSubobject Base,
+                        const CXXRecordDecl *VTableClass) = 0;
+
   /// Get the address point of the vtable for the given base subobject while
-  /// building a constructor or a destructor. On return, NeedsVirtualOffset
-  /// tells if a virtual base adjustment is needed in order to get the offset
-  /// of the base subobject.
-  virtual llvm::Value *getVTableAddressPointInStructor(
-      CodeGenFunction &CGF, const CXXRecordDecl *RD, BaseSubobject Base,
-      const CXXRecordDecl *NearestVBase, bool &NeedsVirtualOffset) = 0;
+  /// building a constructor or a destructor.
+  virtual llvm::Value *
+  getVTableAddressPointInStructor(CodeGenFunction &CGF, const CXXRecordDecl *RD,
+                                  BaseSubobject Base,
+                                  const CXXRecordDecl *NearestVBase) = 0;
 
   /// Get the address point of the vtable for the given base subobject while
   /// building a constexpr.