[stackprotector] Refactor out the end of isInTailCallPosition into the function returnTypeIsEligibleForTailCall.

This allows me to use returnTypeIsEligibleForTailCall in the stack protector pass.

rdar://13935163

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188765 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 17 insertions, 1 deletions

diff --git a/include/llvm/CodeGen/Analysis.h b/include/llvm/CodeGen/Analysis.h
index ce9ca0a058..b2cc7047b3 100644
--- a/include/llvm/CodeGen/Analysis.h
+++ b/include/llvm/CodeGen/Analysis.h
@@ -26,6 +26,7 @@ namespace llvm {
 
 class GlobalVariable;
 class TargetLowering;
+class TargetLoweringBase;
 class SDNode;
 class SDValue;
 class SelectionDAG;
@@ -88,6 +89,14 @@ ISD::CondCode getICmpCondCode(ICmpInst::Predicate Pred);
 /// This function only tests target-independent requirements.
 bool isInTailCallPosition(ImmutableCallSite CS, const TargetLowering &TLI);
 
+/// Test if given that the input instruction is in the tail call position if the
+/// return type or any attributes of the function will inhibit tail call
+/// optimization.
+bool returnTypeIsEligibleForTailCall(const Function *F,
+                                     const Instruction *I,
+                                     const ReturnInst *Ret,
+                                     const TargetLoweringBase &TLI);
+
 } // End llvm namespace
 
 #endif
diff --git a/lib/CodeGen/Analysis.cpp b/lib/CodeGen/Analysis.cpp
index 332a042551..1600c67a7c 100644
--- a/lib/CodeGen/Analysis.cpp
+++ b/lib/CodeGen/Analysis.cpp
@@ -510,6 +510,13 @@ bool llvm::isInTailCallPosition(ImmutableCallSite CS,
         return false;
     }
 
+  return returnTypeIsEligibleForTailCall(ExitBB->getParent(), I, Ret, TLI);
+}
+
+bool llvm::returnTypeIsEligibleForTailCall(const Function *F,
+                                           const Instruction *I,
+                                           const ReturnInst *Ret,
+                                           const TargetLoweringBase &TLI) {
   // If the block ends with a void return or unreachable, it doesn't matter
   // what the call's return type is.
   if (!Ret || Ret->getNumOperands() == 0) return true;
@@ -519,7 +526,7 @@ bool llvm::isInTailCallPosition(ImmutableCallSite CS,
   if (isa<UndefValue>(Ret->getOperand(0))) return true;
 
   // Make sure the attributes attached to each return are compatible.
-  AttrBuilder CallerAttrs(ExitBB->getParent()->getAttributes(),
+  AttrBuilder CallerAttrs(F->getAttributes(),
                           AttributeSet::ReturnIndex);
   AttrBuilder CalleeAttrs(cast<CallInst>(I)->getAttributes(),
                           AttributeSet::ReturnIndex);