In ARC, emit non-peepholed +1s within the full-expression instead

of immediately afterwards.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@174922 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 19 insertions, 17 deletions

diff --git a/lib/CodeGen/CGObjC.cpp b/lib/CodeGen/CGObjC.cpp
index 4583367bb9..b2f5aa3ef1 100644
--- a/lib/CodeGen/CGObjC.cpp
+++ b/lib/CodeGen/CGObjC.cpp
@@ -2497,12 +2497,10 @@ static TryEmitResult tryEmitARCRetainPseudoObject(CodeGenFunction &CGF,
 
 static TryEmitResult
 tryEmitARCRetainScalarExpr(CodeGenFunction &CGF, const Expr *e) {
-  // Look through cleanups.
-  if (const ExprWithCleanups *cleanups = dyn_cast<ExprWithCleanups>(e)) {
-    CGF.enterFullExpression(cleanups);
-    CodeGenFunction::RunCleanupsScope scope(CGF);
-    return tryEmitARCRetainScalarExpr(CGF, cleanups->getSubExpr());
-  }
+  // We should *never* see a nested full-expression here, because if
+  // we fail to emit at +1, our caller must not retain after we close
+  // out the full-expression.
+  assert(!isa<ExprWithCleanups>(e));
 
   // The desired result type, if it differs from the type of the
   // ultimate opaque expression.
@@ -2654,6 +2652,13 @@ static llvm::Value *emitARCRetainLoadOfScalar(CodeGenFunction &CGF,
 /// best-effort attempt to peephole expressions that naturally produce
 /// retained objects.
 llvm::Value *CodeGenFunction::EmitARCRetainScalarExpr(const Expr *e) {
+  // The retain needs to happen within the full-expression.
+  if (const ExprWithCleanups *cleanups = dyn_cast<ExprWithCleanups>(e)) {
+    enterFullExpression(cleanups);
+    RunCleanupsScope scope(*this);
+    return EmitARCRetainScalarExpr(cleanups->getSubExpr());
+  }
+
   TryEmitResult result = tryEmitARCRetainScalarExpr(*this, e);
   llvm::Value *value = result.getPointer();
   if (!result.getInt())
@@ -2663,6 +2668,13 @@ llvm::Value *CodeGenFunction::EmitARCRetainScalarExpr(const Expr *e) {
 
 llvm::Value *
 CodeGenFunction::EmitARCRetainAutoreleaseScalarExpr(const Expr *e) {
+  // The retain needs to happen within the full-expression.
+  if (const ExprWithCleanups *cleanups = dyn_cast<ExprWithCleanups>(e)) {
+    enterFullExpression(cleanups);
+    RunCleanupsScope scope(*this);
+    return EmitARCRetainAutoreleaseScalarExpr(cleanups->getSubExpr());
+  }
+
   TryEmitResult result = tryEmitARCRetainScalarExpr(*this, e);
   llvm::Value *value = result.getPointer();
   if (result.getInt())
@@ -2694,17 +2706,7 @@ llvm::Value *CodeGenFunction::EmitObjCThrowOperand(const Expr *expr) {
   // In ARC, retain and autorelease the expression.
   if (getLangOpts().ObjCAutoRefCount) {
     // Do so before running any cleanups for the full-expression.
-    // tryEmitARCRetainScalarExpr does make an effort to do things
-    // inside cleanups, but there are crazy cases like
-    //   @throw A().foo;
-    // where a full retain+autorelease is required and would
-    // otherwise happen after the destructor for the temporary.
-    if (const ExprWithCleanups *ewc = dyn_cast<ExprWithCleanups>(expr)) {
-      enterFullExpression(ewc);
-      expr = ewc->getSubExpr();
-    }
-
-    CodeGenFunction::RunCleanupsScope cleanups(*this);
+    // EmitARCRetainAutoreleaseScalarExpr does this for us.
     return EmitARCRetainAutoreleaseScalarExpr(expr);
   }