Teach clang to add metadata tags to calls and invokes in ObjC with
-fno-objc-arc-exceptions. This will allow the optimizer to perform
optimizations which are only safe under that flag.
This is a part of rdar://10803830.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@150644 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGCall.cpp b/lib/CodeGen/CGCall.cpp
index b52a897..6690a69 100644
--- a/lib/CodeGen/CGCall.cpp
+++ b/lib/CodeGen/CGCall.cpp
@@ -1593,6 +1593,16 @@
args.add(EmitAnyExprToTemp(E), type);
}
+// In ObjC ARC mode with no ObjC ARC exception safety, tell the ARC
+// optimizer it can aggressively ignore unwind edges.
+void
+CodeGenFunction::AddObjCARCExceptionMetadata(llvm::Instruction *Inst) {
+ if (CGM.getCodeGenOpts().OptimizationLevel != 0 &&
+ !CGM.getCodeGenOpts().ObjCAutoRefCountExceptions)
+ Inst->setMetadata("clang.arc.no_objc_arc_exceptions",
+ CGM.getNoObjCARCExceptionsMetadata());
+}
+
/// Emits a call or invoke instruction to the given function, depending
/// on the current state of the EH stack.
llvm::CallSite
@@ -1600,14 +1610,22 @@
ArrayRef<llvm::Value *> Args,
const Twine &Name) {
llvm::BasicBlock *InvokeDest = getInvokeDest();
- if (!InvokeDest)
- return Builder.CreateCall(Callee, Args, Name);
- llvm::BasicBlock *ContBB = createBasicBlock("invoke.cont");
- llvm::InvokeInst *Invoke = Builder.CreateInvoke(Callee, ContBB, InvokeDest,
- Args, Name);
- EmitBlock(ContBB);
- return Invoke;
+ llvm::Instruction *Inst;
+ if (!InvokeDest)
+ Inst = Builder.CreateCall(Callee, Args, Name);
+ else {
+ llvm::BasicBlock *ContBB = createBasicBlock("invoke.cont");
+ Inst = Builder.CreateInvoke(Callee, ContBB, InvokeDest, Args, Name);
+ EmitBlock(ContBB);
+ }
+
+ // In ObjC ARC mode with no ObjC ARC exception safety, tell the ARC
+ // optimizer it can aggressively ignore unwind edges.
+ if (CGM.getLangOptions().ObjCAutoRefCount)
+ AddObjCARCExceptionMetadata(Inst);
+
+ return Inst;
}
llvm::CallSite
@@ -1916,6 +1934,11 @@
CS.setAttributes(Attrs);
CS.setCallingConv(static_cast<llvm::CallingConv::ID>(CallingConv));
+ // In ObjC ARC mode with no ObjC ARC exception safety, tell the ARC
+ // optimizer it can aggressively ignore unwind edges.
+ if (CGM.getLangOptions().ObjCAutoRefCount)
+ AddObjCARCExceptionMetadata(CS.getInstruction());
+
// If the call doesn't return, finish the basic block and clear the
// insertion point; this allows the rest of IRgen to discard
// unreachable code.