Extract IRGen's constant-emitter into its own helper class and clean up

the interface.

The ultimate goal here is to make it easier to do some more interesting
things in constant emission, like emit constant initializers that have
ignorable side-effects, or doing the majority of an initialization
in-place and then patching up the last few things with calls.  But for
now this is mostly just a refactoring.

llvm-svn: 310964

1 files changed, 7 insertions, 3 deletions

diff --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp
index cd7911a6046b..0217efb9fb4f 100644
--- a/clang/lib/CodeGen/CGExpr.cpp
+++ b/clang/lib/CodeGen/CGExpr.cpp
@@ -20,6 +20,7 @@
 #include "CGRecordLayout.h"
 #include "CodeGenFunction.h"
 #include "CodeGenModule.h"
+#include "ConstantEmitter.h"
 #include "TargetInfo.h"
 #include "clang/AST/ASTContext.h"
 #include "clang/AST/Attr.h"
@@ -356,7 +357,7 @@ static Address createReferenceTemporary(CodeGenFunction &CGF,
     if (CGF.CGM.getCodeGenOpts().MergeAllConstants &&
         (Ty->isArrayType() || Ty->isRecordType()) &&
         CGF.CGM.isTypeConstant(Ty, true))
-      if (llvm::Constant *Init = CGF.CGM.EmitConstantExpr(Inner, Ty, &CGF)) {
+      if (auto Init = ConstantEmitter(CGF).tryEmitAbstract(Inner, Ty)) {
         if (auto AddrSpace = CGF.getTarget().getConstantAddressSpace()) {
           auto AS = AddrSpace.getValue();
           auto *GV = new llvm::GlobalVariable(
@@ -1318,7 +1319,8 @@ CodeGenFunction::tryEmitAsConstant(DeclRefExpr *refExpr) {
     return ConstantEmission();
 
   // Emit as a constant.
-  llvm::Constant *C = CGM.EmitConstantValue(result.Val, resultType, this);
+  auto C = ConstantEmitter(*this).emitAbstract(refExpr->getLocation(),
+                                               result.Val, resultType);
 
   // Make sure we emit a debug reference to the global variable.
   // This should probably fire even for
@@ -2283,7 +2285,9 @@ LValue CodeGenFunction::EmitDeclRefLValue(const DeclRefExpr *E) {
         !(E->refersToEnclosingVariableOrCapture() && CapturedStmtInfo &&
           LocalDeclMap.count(VD))) {
       llvm::Constant *Val =
-        CGM.EmitConstantValue(*VD->evaluateValue(), VD->getType(), this);
+        ConstantEmitter(*this).emitAbstract(E->getLocation(),
+                                            *VD->evaluateValue(),
+                                            VD->getType());
       assert(Val && "failed to emit reference constant expression");
       // FIXME: Eventually we will want to emit vector element references.