[LLVM-C] Correct The Current Debug Location Accessors

[CodaFi]

Summary

Deprecate the existing accessors for the "current debug location" of an IRBuilder. The setter could not handle being reset to NULL, and the getter would create bogus metadata if the NULL location was returned. Provide direct metadata-based accessors instead.

[whitequark]

llvm/include/llvm-c/Core.h

3531 ↗

(On Diff #194388)

Let's add the 2 suffix here for consistency as well.

[CodaFi]

llvm/include/llvm-c/Core.h

3531 ↗

(On Diff #194388)

This API didn't change, the diff is just a mess!

[whitequark]

llvm/include/llvm-c/Core.h

3531 ↗

(On Diff #194388)

Oh... Can you add some docs for this API? I had to look up the C++ source to even understand what it's supposed to do.

[CodaFi]

Add documentation to LLVMSetInstDebugLocation

[whitequark]

LGTM

[sammccall]

These symbols conflict with identically-named symbols in llvm/bindings/go/llvm/IRBindings.h, going to revert (I don't know what the right name is, and in the C API that's probably important)

[CodaFi]

*sigh*, I'll resubmit this and nuke the ones in the Go bindings then.

llvm/trunk/include/llvm-c/Core.h

 LLVMBasicBlockRef LLVMGetInsertBlock(LLVMBuilderRef Builder);
 void LLVMClearInsertionPosition(LLVMBuilderRef Builder);
 void LLVMInsertIntoBuilder(LLVMBuilderRef Builder, LLVMValueRef Instr);
 void LLVMInsertIntoBuilderWithName(LLVMBuilderRef Builder, LLVMValueRef Instr,
                                    const char *Name);
 void LLVMDisposeBuilder(LLVMBuilderRef Builder);
 
 /* Metadata */
+
+/**
+ * Get location information used by debugging information.
+ *
+ * @see llvm::IRBuilder::getCurrentDebugLocation()
+ */
+LLVMMetadataRef LLVMGetCurrentDebugLocation2(LLVMBuilderRef Builder);
+
+/**
+ * Set location information used by debugging information.
+ *
+ * To clear the location metadata of the given instruction, pass NULL to \p Loc.
+ *
+ * @see llvm::IRBuilder::SetCurrentDebugLocation()
+ */
+void LLVMSetCurrentDebugLocation2(LLVMBuilderRef Builder, LLVMMetadataRef Loc);
+
+/**
+ * Attempts to set the debug location for the given instruction using the
+ * current debug location for the given builder.  If the builder has no current
+ * debug location, this function is a no-op.
+ *
+ * @see llvm::IRBuilder::SetInstDebugLocation()
+ */
+void LLVMSetInstDebugLocation(LLVMBuilderRef Builder, LLVMValueRef Inst);
+  
+/**
+ * Deprecated: Passing the NULL location will crash.
+ * Use LLVMGetCurrentDebugLocation2 instead.
+ */
 void LLVMSetCurrentDebugLocation(LLVMBuilderRef Builder, LLVMValueRef L);
+/**
+ * Deprecated: Returning the NULL location will crash.
+ * Use LLVMGetCurrentDebugLocation2 instead.
+ */
 LLVMValueRef LLVMGetCurrentDebugLocation(LLVMBuilderRef Builder);
-void LLVMSetInstDebugLocation(LLVMBuilderRef Builder, LLVMValueRef Inst);
 
 /* Terminators */
 LLVMValueRef LLVMBuildRetVoid(LLVMBuilderRef);
 LLVMValueRef LLVMBuildRet(LLVMBuilderRef, LLVMValueRef V);
 LLVMValueRef LLVMBuildAggregateRet(LLVMBuilderRef, LLVMValueRef *RetVals,
                                    unsigned N);
 LLVMValueRef LLVMBuildBr(LLVMBuilderRef, LLVMBasicBlockRef Dest);
 LLVMValueRef LLVMBuildCondBr(LLVMBuilderRef, LLVMValueRef If,

llvm/trunk/lib/IR/Core.cpp

 }
 
 void LLVMDisposeBuilder(LLVMBuilderRef Builder) {
   delete unwrap(Builder);
 }
 
 /*--.. Metadata builders ...................................................--*/
 
+LLVMMetadataRef LLVMGetCurrentDebugLocation2(LLVMBuilderRef Builder) {
+  return wrap(unwrap(Builder)->getCurrentDebugLocation().getAsMDNode());
+}
+
+void LLVMSetCurrentDebugLocation2(LLVMBuilderRef Builder, LLVMMetadataRef Loc) {
+  if (Loc)
+    unwrap(Builder)->SetCurrentDebugLocation(DebugLoc(unwrap<MDNode>(Loc)));
+  else
+    unwrap(Builder)->SetCurrentDebugLocation(DebugLoc());
+}
+
 void LLVMSetCurrentDebugLocation(LLVMBuilderRef Builder, LLVMValueRef L) {
   MDNode *Loc =
       L ? cast<MDNode>(unwrap<MetadataAsValue>(L)->getMetadata()) : nullptr;
   unwrap(Builder)->SetCurrentDebugLocation(DebugLoc(Loc));
 }
 
 LLVMValueRef LLVMGetCurrentDebugLocation(LLVMBuilderRef Builder) {
   LLVMContext &Context = unwrap(Builder)->getContext();
   return wrap(MetadataAsValue::get(
       Context, unwrap(Builder)->getCurrentDebugLocation().getAsMDNode()));
 }
 
 void LLVMSetInstDebugLocation(LLVMBuilderRef Builder, LLVMValueRef Inst) {
   unwrap(Builder)->SetInstDebugLocation(unwrap<Instruction>(Inst));
 }
 
-
 /*--.. Instruction builders ................................................--*/
 
 LLVMValueRef LLVMBuildRetVoid(LLVMBuilderRef B) {
   return wrap(unwrap(B)->CreateRetVoid());
 }
 
 LLVMValueRef LLVMBuildRet(LLVMBuilderRef B, LLVMValueRef V) {
   return wrap(unwrap(B)->CreateRet(unwrap(V)));