Expose TailCallKind via the LLVM C API

Summary: This exposes `CallInst`'s tail call kind via new `LLVMGetTailCallKind` and `LLVMSetTailCallKind` functions. The motivation for this is to be able to see `musttail` for languages that require mandatory tail calls for correctness. Today only the weaker `LLVMSetTail` is exposed and there is no way to set `GuaranteedTailCallOpt` via the C API.

Reviewers: CodaFi, jyknight, deadalnix, rnk

Reviewed By: CodaFi

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D66061

llvm-svn: 368945

1 files changed, 25 insertions, 0 deletions

diff --git a/llvm/include/llvm-c/Core.h b/llvm/include/llvm-c/Core.h
index cac2f297056..00d151c4541 100644
--- a/llvm/include/llvm-c/Core.h
+++ b/llvm/include/llvm-c/Core.h
@@ -452,6 +452,13 @@ enum {
 
 typedef unsigned LLVMAttributeIndex;
 
+typedef enum {
+  LLVMTailCallKindNone,
+  LLVMTailCallKindTail,
+  LLVMTailCallKindMustTail,
+  LLVMTailCallKindNoTail
+} LLVMTailCallKind;
+
 /**
  * @}
  */
@@ -3264,6 +3271,24 @@ LLVMBool LLVMIsTailCall(LLVMValueRef CallInst);
 void LLVMSetTailCall(LLVMValueRef CallInst, LLVMBool IsTailCall);
 
 /**
+ * Obtains the kind of tail call for a call instruction.
+ *
+ * This only works on llvm::CallInst instructions.
+ *
+ * @see llvm::CallInst::getTailCallKind()
+ */
+LLVMTailCallKind LLVMGetTailCallKind(LLVMValueRef CallInst);
+
+/**
+ * Set the kind of tail call for a call instruction.
+ *
+ * This only works on llvm::CallInst instructions.
+ *
+ * @see llvm::CallInst::setTailCallKind()
+ */
+void LLVMSetTailCallKind(LLVMValueRef CallInst, LLVMTailCallKind TCK);
+
+/**
  * Return the normal destination basic block.
  *
  * This only works on llvm::InvokeInst instructions.