[llvm-c] Add LLVMSetTailCallKind and LLVMGetTailCallKind

Reviewed By: aeubanks

Differential Revision: https://reviews.llvm.org/D153107

Author: yamt

llvm/docs/ReleaseNotes.rst

@@ -116,6 +116,10 @@ Changes to the Python bindings
 Changes to the C API
 --------------------
 
+* Added ``LLVMGetTailCallKind`` and ``LLVMSetTailCallKind`` to
+  allow getting and setting ``tail``, ``musttail``, and ``notail``
+  attributes on call instructions.
+
 Changes to the CodeGen infrastructure
 -------------------------------------
 

llvm/include/llvm-c/Core.h

@@ -468,6 +468,20 @@ enum {
   LLVMAttributeFunctionIndex = -1,
 };
 
+/**
+ * Tail call kind for LLVMSetTailCallKind and LLVMGetTailCallKind.
+ *
+ * Note that 'musttail' implies 'tail'.
+ *
+ * @see CallInst::TailCallKind
+ */
+typedef enum {
+  LLVMTailCallKindNone = 0,
+  LLVMTailCallKindTail = 1,
+  LLVMTailCallKindMustTail = 2,
+  LLVMTailCallKindNoTail = 3,
+} LLVMTailCallKind;
+
 typedef unsigned LLVMAttributeIndex;
 
 /**
@@ -3429,6 +3443,20 @@ LLVMBool LLVMIsTailCall(LLVMValueRef CallInst);
  */
 void LLVMSetTailCall(LLVMValueRef CallInst, LLVMBool IsTailCall);
 
+/**
+ * Obtain a tail call kind of the call instruction.
+ *
+ * @see llvm::CallInst::setTailCallKind()
+ */
+LLVMTailCallKind LLVMGetTailCallKind(LLVMValueRef CallInst);
+
+/**
+ * Set the call kind of the call instruction.
+ *
+ * @see llvm::CallInst::getTailCallKind()
+ */
+void LLVMSetTailCallKind(LLVMValueRef CallInst, LLVMTailCallKind kind);
+
 /**
  * Return the normal destination basic block.
  *

llvm/lib/IR/Core.cpp

@@ -2896,6 +2896,14 @@ void LLVMSetTailCall(LLVMValueRef Call, LLVMBool isTailCall) {
   unwrap<CallInst>(Call)->setTailCall(isTailCall);
 }
 
+LLVMTailCallKind LLVMGetTailCallKind(LLVMValueRef Call) {
+  return (LLVMTailCallKind)unwrap<CallInst>(Call)->getTailCallKind();
+}
+
+void LLVMSetTailCallKind(LLVMValueRef Call, LLVMTailCallKind kind) {
+  unwrap<CallInst>(Call)->setTailCallKind((CallInst::TailCallKind)kind);
+}
+
 /*--.. Operations on invoke instructions (only) ............................--*/
 
 LLVMBasicBlockRef LLVMGetNormalDest(LLVMValueRef Invoke) {

llvm/test/Bindings/llvm-c/echo.ll

@@ -98,6 +98,21 @@ define i32 @call() {
   ret i32 %1
 }
 
+define i32 @tailcall() {
+  %1 = tail call i32 @call()
+  ret i32 %1
+}
+
+define i32 @musttailcall() {
+  %1 = musttail call i32 @call()
+  ret i32 %1
+}
+
+define i32 @notailcall() {
+  %1 = notail call i32 @call()
+  ret i32 %1
+}
+
 define i32 @cond(i32 %a, i32 %b) {
   br label %br
 unreachable:

llvm/tools/llvm-c-test/echo.cpp

@@ -736,7 +736,7 @@ struct FunCloner {
         LLVMTypeRef FnTy = CloneType(LLVMGetCalledFunctionType(Src));
         LLVMValueRef Fn = CloneValue(LLVMGetCalledValue(Src));
         Dst = LLVMBuildCall2(Builder, FnTy, Fn, Args.data(), ArgCount, Name);
-        LLVMSetTailCall(Dst, LLVMIsTailCall(Src));
+        LLVMSetTailCallKind(Dst, LLVMGetTailCallKind(Src));
         CloneAttrs(Src, Dst);
         break;
       }