constexpr irgen: Add irgen support for APValue::Struct, APValue::Union,

APValue::Array and APValue::MemberPointer. All APValue values can now be emitted
as constants.

Add new CGCXXABI entry point for emitting an APValue MemberPointer. The other
entrypoints dealing with constant member pointers are no longer necessary and
will be removed in a later change.

Switch codegen from using EvaluateAsRValue/EvaluateAsLValue to
VarDecl::evaluateValue. This performs caching and deals with the nasty cases in
C++11 where a non-const object's initializer can refer indirectly to
previously-initialized fields within the same object.

Building the intermediate APValue object incurs a measurable performance hit on
pathological testcases with huge initializer lists, so we continue to build IR
directly from the Expr nodes for array and record types outside of C++11.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@148178 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 10 insertions, 0 deletions

diff --git a/lib/CodeGen/CodeGenModule.h b/lib/CodeGen/CodeGenModule.h
index 4c839d1353..d94d10afc1 100644
--- a/lib/CodeGen/CodeGenModule.h
+++ b/lib/CodeGen/CodeGenModule.h
@@ -687,12 +687,22 @@ public:
 
   llvm::Constant *getMemberPointerConstant(const UnaryOperator *e);
 
+  /// EmitConstantInit - Try to emit the initializer for the given declaration
+  /// as a constant; returns 0 if the expression cannot be emitted as a
+  /// constant.
+  llvm::Constant *EmitConstantInit(const VarDecl &D, CodeGenFunction *CGF = 0);
+
   /// EmitConstantExpr - Try to emit the given expression as a
   /// constant; returns 0 if the expression cannot be emitted as a
   /// constant.
   llvm::Constant *EmitConstantExpr(const Expr *E, QualType DestType,
                                    CodeGenFunction *CGF = 0);
 
+  /// EmitConstantValue - Try to emit the given constant value as a
+  /// constant; returns 0 if the value cannot be emitted as a constant.
+  llvm::Constant *EmitConstantValue(const APValue &Value, QualType DestType,
+                                    CodeGenFunction *CGF = 0);
+
   /// EmitNullConstant - Return the result of value-initializing the given
   /// type, i.e. a null expression of the given type.  This is usually,
   /// but not always, an LLVM null constant.