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

[chandlerc]

Summary

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.

[chandlerc]

Sending this for pre-commit review as I want to be sure I'm doing the right thing w/ the C-API here.

[chandlerc]

Ping? Would be really nice to get a review here.

[chandlerc]

Ping again! Also rebase...

[chandlerc]

Ping, rebase, and update to remove all but the type system bits to match the
progress outside of the C API.

[jyknight]

llvm/include/llvm-c/Core.h

2921

I would actually make this function "LLVMIsATerminatorInst", *replacing* the LLVMIsATermiantorInst function defined using "macro" at the top. (A similar thing was done with e.g. LLVMIsAMDNode). With that, I think this change will be 100% compatible in the C API.

3063–3064

(LLVMIsATerminator)

[chandlerc]

Update based on Jame's suggestion.

[chandlerc]

Fix one more place.

[chandlerc]

Done.

[jyknight]

LGTM.

llvm/include/llvm-c/Core.h

3064

Typo: "eturns"

llvm/include/llvm-c/Core.h

  *   * The instruction has no parent
  *   * The instruction has no name
  *
  * @see llvm::Instruction::clone()
  */
 LLVMValueRef LLVMInstructionClone(LLVMValueRef Inst);
 
 /**
+ * Determine whether an instruction is a terminator.
+ *
+ * @see llvm::Instruction::isTerminator()
+ */
+LLVMBool LLVMIsTerminator(LLVMValueRef Inst);
+
+/**
  * @defgroup LLVMCCoreValueInstructionCall Call Sites and Invocations
  *
  * Functions in this group apply to instructions that refer to call
  * sites and invocations. These correspond to C++ types in the
  * llvm::CallInst class tree.
  *
  * @{
  */

 
 /**
  * @}
  */
 
 /**
  * @defgroup LLVMCCoreValueInstructionTerminator Terminators
  *
- * Functions in this group only apply to instructions that map to
- * llvm::TerminatorInst instances.
+ * Functions in this group only apply to instructions for which LLVMIsTerminator
+ * returns true.
  *
  * @{
  */
 
 /**
  * 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);
 
 /**
  * Return if a branch is conditional.
  *
  * This only works on llvm::BranchInst instructions.
  *

llvm/lib/IR/Core.cpp

 }
 
 LLVMValueRef LLVMInstructionClone(LLVMValueRef Inst) {
   if (Instruction *C = dyn_cast<Instruction>(unwrap(Inst)))
     return wrap(C->clone());
   return nullptr;
 }
 
+LLVMBool LLVMIsTerminator(LLVMValueRef Inst) {
+  if (Instruction *I = dyn_cast<Instruction>(unwrap(Inst)))
+    return I->isTerminator();
+  return false;
+}
+
 unsigned LLVMGetNumArgOperands(LLVMValueRef Instr) {
   if (FuncletPadInst *FPI = dyn_cast<FuncletPadInst>(unwrap(Instr))) {
     return FPI->getNumArgOperands();
   }
   return CallSite(unwrap<Instruction>(Instr)).getNumArgOperands();
 }
 
 /*--.. Call and invoke instructions ........................................--*/
if (CleanupReturnInst *CRI = dyn_cast<CleanupReturnInst>(unwrap(Invoke))) {
     return CSI->setUnwindDest(unwrap(B));
   }
   unwrap<InvokeInst>(Invoke)->setUnwindDest(unwrap(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) ............................--*/
 
 LLVMBool LLVMIsConditional(LLVMValueRef Branch) {
   return unwrap<BranchInst>(Branch)->isConditional();
 }