[TI removal] Update the C API for the move away from `TerminatorInst`.

This updates the C API for the removal of `TerminatorInst`. It converts
the type query to a predicate query and moves the generic methods to
work on `Instruction` instances that satisfy this predicate rather than
requiring a specific type. It also clarifies that the C API wrapping
`BasicBlock::getTerminator` just returns an `Instruction`. Because this
was always wrapped opaquely as a value and the functions consuming these
values will work on `Instruction` objects, this shouldn't break any
clients.

This is a completely compatible change to the C API.

Differential Revision: https://reviews.llvm.org/D52968

llvm-svn: 344764

llvm/include/llvm-c/Core.h

@@ -1539,7 +1539,6 @@ LLVMTypeRef LLVMX86MMXType(void);
       macro(SelectInst)                     \
       macro(ShuffleVectorInst)              \
       macro(StoreInst)                      \
-      macro(TerminatorInst)                 \
       macro(BranchInst)                     \
       macro(IndirectBrInst)                 \
       macro(InvokeInst)                     \
@@ -2679,7 +2678,7 @@ LLVMValueRef LLVMGetBasicBlockParent(LLVMBasicBlockRef BB);
  * If the basic block does not have a terminator (it is not well-formed
  * if it doesn't), then NULL is returned.
  *
- * The returned LLVMValueRef corresponds to a llvm::TerminatorInst.
+ * The returned LLVMValueRef corresponds to an llvm::Instruction.
  *
  * @see llvm::BasicBlock::getTerminator()
  */
@@ -2951,6 +2950,15 @@ LLVMRealPredicate LLVMGetFCmpPredicate(LLVMValueRef Inst);
  */
 LLVMValueRef LLVMInstructionClone(LLVMValueRef Inst);
 
+/**
+ * Determine whether an instruction is a terminator. This routine is named to
+ * be compatible with historical functions that did this by querying the
+ * underlying C++ type.
+ *
+ * @see llvm::Instruction::isTerminator()
+ */
+LLVMValueRef LLVMIsATerminatorInst(LLVMValueRef Inst);
+
 /**
  * @defgroup LLVMCCoreValueInstructionCall Call Sites and Invocations
  *
@@ -3091,8 +3099,8 @@ void LLVMSetUnwindDest(LLVMValueRef InvokeInst, LLVMBasicBlockRef B);
 /**
  * @defgroup LLVMCCoreValueInstructionTerminator Terminators
  *
- * Functions in this group only apply to instructions that map to
+ * Functions in this group only apply to instructions for which
- * llvm::TerminatorInst instances.
+ * LLVMIsATerminatorInst returns true.
  *
  * @{
  */
@@ -3100,21 +3108,21 @@ void LLVMSetUnwindDest(LLVMValueRef InvokeInst, LLVMBasicBlockRef B);
 /**
  * Return the number of successors that this terminator has.
  *
- * @see llvm::TerminatorInst::getNumSuccessors
+ * @see llvm::Instruction::getNumSuccessors
  */
 unsigned LLVMGetNumSuccessors(LLVMValueRef Term);
 
 /**
  * Return the specified successor.
  *
- * @see llvm::TerminatorInst::getSuccessor
+ * @see llvm::Instruction::getSuccessor
  */
 LLVMBasicBlockRef LLVMGetSuccessor(LLVMValueRef Term, unsigned i);
 
 /**
  * Update the specified successor to point at the provided block.
  *
- * @see llvm::TerminatorInst::setSuccessor
+ * @see llvm::Instruction::setSuccessor
  */
 void LLVMSetSuccessor(LLVMValueRef Term, unsigned i, LLVMBasicBlockRef block);
 

llvm/lib/IR/Core.cpp

@@ -2595,6 +2595,11 @@ LLVMValueRef LLVMInstructionClone(LLVMValueRef Inst) {
   return nullptr;
 }
 
+LLVMValueRef LLVMIsATerminatorInst(LLVMValueRef Inst) {
+  Instruction *I = dyn_cast<Instruction>(unwrap(Inst));
+  return (I && I->isTerminator()) ? wrap(I) : nullptr;
+}
+
 unsigned LLVMGetNumArgOperands(LLVMValueRef Instr) {
   if (FuncletPadInst *FPI = dyn_cast<FuncletPadInst>(unwrap(Instr))) {
     return FPI->getNumArgOperands();
@@ -2710,15 +2715,15 @@ void LLVMSetUnwindDest(LLVMValueRef Invoke, LLVMBasicBlockRef B) {
 /*--.. Operations on terminators ...........................................--*/
 
 unsigned LLVMGetNumSuccessors(LLVMValueRef Term) {
-  return unwrap<TerminatorInst>(Term)->getNumSuccessors();
+  return unwrap<Instruction>(Term)->getNumSuccessors();
 }
 
 LLVMBasicBlockRef LLVMGetSuccessor(LLVMValueRef Term, unsigned i) {
-  return wrap(unwrap<TerminatorInst>(Term)->getSuccessor(i));
+  return wrap(unwrap<Instruction>(Term)->getSuccessor(i));
 }
 
 void LLVMSetSuccessor(LLVMValueRef Term, unsigned i, LLVMBasicBlockRef block) {
-  return unwrap<TerminatorInst>(Term)->setSuccessor(i,unwrap(block));
+  return unwrap<Instruction>(Term)->setSuccessor(i, unwrap(block));
 }
 
 /*--.. Operations on branch instructions (only) ............................--*/