Add LLVM-C interface for Windows x64 SEH instructions

[NickBarnes]

Summary

The LLVM-C interface provides no means to construct catchswitch, catchpad, catchret, cleanuppad, or cleanupret instructions, or to attach a funclet operand bundle to call or invoke instructions (which is required in cleanuppad blocks).

This patch provides the most basic functionality, and is sufficient for the project I'm working on. More could be done, but this much is required to get anywhere.

See https://llvm.org/bugs/show_bug.cgi?id=30785

[deadalnix]

A few things here.

1/ Please add a test for this. You can use the echo facility to do so. You can grep for 'llvm-c-test --echo' in the test folder to find some examples of this. This will ensure you can read/write this IR properly.
2/ The formatting is off all over the place. Please follow the usual formatting. You can use clang-format to help you do so.

[deadalnix]

Any news here ? This is a pretty good patch if we put aside the lack of tests. With a test on it, I'd merge.

[Wallbraker]

include/llvm-c/Core.h

1526

We probably also want one that takes a Context for those of us that manages those ourselves.

[Wallbraker]

This can be closed, as changes has landed in a different review. See D45100.

include/llvm-c/Core.h

 LLVMValueRef LLVMConstPointerNull(LLVMTypeRef Ty);
 
 /**
+ * Obtain the constant token "none", used in SEH instructions.
+ */
+LLVMValueRef LLVMConstTokenNone(void);
+
+/**
  * @defgroup LLVMCCoreValueConstantScalar Scalar constants
  *
  * Functions in this group model LLVMValueRef instances that correspond

                              LLVMValueRef *Args, unsigned NumArgs,
                              LLVMBasicBlockRef Then, LLVMBasicBlockRef Catch,
                              const char *Name);
+LLVMValueRef LLVMBuildInvokeInPad(LLVMBuilderRef B, LLVMValueRef Fn,
+                                  LLVMValueRef *Args, unsigned NumArgs,
+                                  LLVMBasicBlockRef Then, LLVMBasicBlockRef Catch,
+          LLVMValueRef Pad, const char *Name);
 LLVMValueRef LLVMBuildLandingPad(LLVMBuilderRef B, LLVMTypeRef Ty,
                                  LLVMValueRef PersFn, unsigned NumClauses,
                                  const char *Name);
+LLVMValueRef LLVMBuildCatchSwitch(LLVMBuilderRef B, LLVMValueRef ParentPad,
+          LLVMBasicBlockRef UnwindBB, unsigned NumHandlers,
+          const char *Name);
+void LLVMAddHandler(LLVMValueRef CatchSwitch, LLVMBasicBlockRef HandlerVal);
+LLVMValueRef LLVMBuildCatchPad(LLVMBuilderRef B, LLVMValueRef ParentPad,
+             LLVMValueRef *Args, unsigned NumArgs,
+             const char *Name);
+LLVMValueRef LLVMBuildCleanupPad(LLVMBuilderRef B, LLVMValueRef ParentPad,
+         LLVMValueRef *Args, unsigned NumArgs,
+         const char *Name);
+LLVMValueRef LLVMBuildCatchRet(LLVMBuilderRef B, LLVMValueRef CatchPad,
+             LLVMBasicBlockRef BB);
+LLVMValueRef LLVMBuildCleanupRet(LLVMBuilderRef B, LLVMValueRef CleanupPad,
+         LLVMBasicBlockRef UnwindBB);
 LLVMValueRef LLVMBuildResume(LLVMBuilderRef B, LLVMValueRef Exn);
 LLVMValueRef LLVMBuildUnreachable(LLVMBuilderRef);
 

 LLVMValueRef LLVMBuildCall(LLVMBuilderRef, LLVMValueRef Fn,
                            LLVMValueRef *Args, unsigned NumArgs,
                            const char *Name);
+LLVMValueRef LLVMBuildCallInPad(LLVMBuilderRef B, LLVMValueRef Fn,
+                                LLVMValueRef *Args, unsigned NumArgs,
+        LLVMValueRef Pad, const char *Name);
 LLVMValueRef LLVMBuildSelect(LLVMBuilderRef, LLVMValueRef If,
                              LLVMValueRef Then, LLVMValueRef Else,
                              const char *Name);

lib/IR/Core.cpp

   return wrap(ConstantPointerNull::get(unwrap<PointerType>(Ty)));
 }
 
+LLVMValueRef LLVMConstTokenNone(void) {
+    return wrap(ConstantTokenNone::get(*unwrap(LLVMGetGlobalContext())));
+}
+
 /*--.. Operations on metadata nodes ........................................--*/
 
 LLVMValueRef LLVMMDStringInContext(LLVMContextRef C, const char *Str,

                                       Name));
 }
 
+LLVMValueRef LLVMBuildInvokeInPad(LLVMBuilderRef B, LLVMValueRef Fn,
+                                  LLVMValueRef *Args, unsigned NumArgs,
+                                  LLVMBasicBlockRef Then, LLVMBasicBlockRef Catch,
+          LLVMValueRef Pad, const char *Name) {
+  SmallVector<OperandBundleDef, 1> BundleList;
+  BundleList.emplace_back("funclet", unwrap<Instruction>(Pad));
+  return wrap(unwrap(B)->CreateInvoke(unwrap(Fn), unwrap(Then), unwrap(Catch),
+                                      makeArrayRef(unwrap(Args), NumArgs),
+              BundleList, Name));
+}
+
 LLVMValueRef LLVMBuildLandingPad(LLVMBuilderRef B, LLVMTypeRef Ty,
                                  LLVMValueRef PersFn, unsigned NumClauses,
                                  const char *Name) {

   return wrap(unwrap(B)->CreateResume(unwrap(Exn)));
 }
 
+LLVMValueRef LLVMBuildCatchSwitch(LLVMBuilderRef B,
+          LLVMValueRef ParentPad,
+          LLVMBasicBlockRef UnwindBB,
+          unsigned NumHandlers,
+          const char *Name) {
+    return wrap(unwrap(B)->CreateCatchSwitch(unwrap(ParentPad), unwrap(UnwindBB),
+               NumHandlers, Name));
+}
+
+void LLVMAddHandler(LLVMValueRef CatchSwitch, LLVMBasicBlockRef handler) {
+    unwrap<CatchSwitchInst>(CatchSwitch)->addHandler(unwrap(handler));
+}
+
+LLVMValueRef LLVMBuildCatchPad(LLVMBuilderRef B,
+             LLVMValueRef ParentPad,
+             LLVMValueRef *Args,
+             unsigned NumArgs,
+             const char *Name) {
+    ArrayRef<Value *> ArgList(unwrap(Args), NumArgs);
+    return wrap(unwrap(B)->CreateCatchPad(unwrap(ParentPad), ArgList, Name));
+}
+
+LLVMValueRef LLVMBuildCleanupPad(LLVMBuilderRef B,
+         LLVMValueRef ParentPad,
+         LLVMValueRef *Args,
+         unsigned NumArgs,
+         const char *Name) {
+    ArrayRef<Value *> ArgList(unwrap(Args), NumArgs);
+    return wrap(unwrap(B)->CreateCleanupPad(unwrap(ParentPad), ArgList, Name));
+}
+
+LLVMValueRef LLVMBuildCatchRet(LLVMBuilderRef B,
+         LLVMValueRef CatchPad,
+         LLVMBasicBlockRef BB) {
+    return wrap(unwrap(B)->CreateCatchRet(unwrap<CatchPadInst>(CatchPad), unwrap(BB)));
+}
+
+LLVMValueRef LLVMBuildCleanupRet(LLVMBuilderRef B,
+         LLVMValueRef CleanupPad,
+         LLVMBasicBlockRef UnwindBB) {
+    return wrap(unwrap(B)->CreateCleanupRet(unwrap<CleanupPadInst>(CleanupPad), unwrap(UnwindBB)));
+}
+
+
 LLVMValueRef LLVMBuildUnreachable(LLVMBuilderRef B) {
   return wrap(unwrap(B)->CreateUnreachable());
 }

                                     Name));
 }
 
+LLVMValueRef LLVMBuildCallInPad(LLVMBuilderRef B, LLVMValueRef Fn,
+                                LLVMValueRef *Args, unsigned NumArgs,
+        LLVMValueRef Pad, const char *Name) {
+  SmallVector<OperandBundleDef, 1> BundleList;
+  BundleList.emplace_back("funclet", unwrap<Instruction>(Pad));
+  return wrap(unwrap(B)->CreateCall(unwrap(Fn),
+                                    makeArrayRef(unwrap(Args), NumArgs),
+            BundleList,
+                                    Name));
+}
+
 LLVMValueRef LLVMBuildSelect(LLVMBuilderRef B, LLVMValueRef If,
                              LLVMValueRef Then, LLVMValueRef Else,
                              const char *Name) {