[llvm-c] Add bindings for DbgRecord (#166383)

In the LLVM-C library, there is currently no way to get information about a
DbgRecord - which is the new way to attach debug information to llvm
instructions.

We can only iterate on debug records with LLVMGetFirstDbgRecord/
LLVMGetLastDbgRecord/LLVMGetNextDbgRecord, but there is no way to read
information.

This PR adds utility functions to read DbgRecord information.

Author: arthaud

llvm/include/llvm-c/Core.h

@@ -531,6 +531,13 @@ enum {
  */
 typedef unsigned LLVMGEPNoWrapFlags;
 
+typedef enum {
+  LLVMDbgRecordLabel,
+  LLVMDbgRecordDeclare,
+  LLVMDbgRecordValue,
+  LLVMDbgRecordAssign,
+} LLVMDbgRecordKind;
+
 /**
  * @}
  */
@@ -3896,6 +3903,37 @@ LLVM_C_ABI LLVMDbgRecordRef LLVMGetNextDbgRecord(LLVMDbgRecordRef DbgRecord);
 LLVM_C_ABI LLVMDbgRecordRef
 LLVMGetPreviousDbgRecord(LLVMDbgRecordRef DbgRecord);
 
+/**
+ * Get the debug location attached to the debug record.
+ *
+ * @see llvm::DbgRecord::getDebugLoc()
+ */
+LLVMMetadataRef LLVMDbgRecordGetDebugLoc(LLVMDbgRecordRef Rec);
+
+LLVMDbgRecordKind LLVMDbgRecordGetKind(LLVMDbgRecordRef Rec);
+
+/**
+ * Get the value of the DbgVariableRecord.
+ *
+ * @see llvm::DbgVariableRecord::getValue()
+ */
+LLVMValueRef LLVMDbgVariableRecordGetValue(LLVMDbgRecordRef Rec,
+                                           unsigned OpIdx);
+
+/**
+ * Get the debug info variable of the DbgVariableRecord.
+ *
+ * @see llvm::DbgVariableRecord::getVariable()
+ */
+LLVMMetadataRef LLVMDbgVariableRecordGetVariable(LLVMDbgRecordRef Rec);
+
+/**
+ * Get the debug info expression of the DbgVariableRecord.
+ *
+ * @see llvm::DbgVariableRecord::getExpression()
+ */
+LLVMMetadataRef LLVMDbgVariableRecordGetExpression(LLVMDbgRecordRef Rec);
+
 /**
  * @defgroup LLVMCCoreValueInstructionCall Call Sites and Invocations
  *

llvm/lib/IR/Core.cpp

@@ -3036,6 +3036,37 @@ LLVMDbgRecordRef LLVMGetPreviousDbgRecord(LLVMDbgRecordRef Rec) {
   return wrap(&*--I);
 }
 
+LLVMMetadataRef LLVMDbgRecordGetDebugLoc(LLVMDbgRecordRef Rec) {
+  return wrap(unwrap<DbgRecord>(Rec)->getDebugLoc().getAsMDNode());
+}
+
+LLVMDbgRecordKind LLVMDbgRecordGetKind(LLVMDbgRecordRef Rec) {
+  DbgRecord *Record = unwrap<DbgRecord>(Rec);
+  if (isa<DbgLabelRecord>(Record))
+    return LLVMDbgRecordLabel;
+  DbgVariableRecord *VariableRecord = dyn_cast<DbgVariableRecord>(Record);
+  assert(VariableRecord && "unexpected record");
+  if (VariableRecord->isDbgDeclare())
+    return LLVMDbgRecordDeclare;
+  if (VariableRecord->isDbgValue())
+    return LLVMDbgRecordValue;
+  assert(VariableRecord->isDbgAssign() && "unexpected record");
+  return LLVMDbgRecordAssign;
+}
+
+LLVMValueRef LLVMDbgVariableRecordGetValue(LLVMDbgRecordRef Rec,
+                                           unsigned OpIdx) {
+  return wrap(unwrap<DbgVariableRecord>(Rec)->getValue(OpIdx));
+}
+
+LLVMMetadataRef LLVMDbgVariableRecordGetVariable(LLVMDbgRecordRef Rec) {
+  return wrap(unwrap<DbgVariableRecord>(Rec)->getRawVariable());
+}
+
+LLVMMetadataRef LLVMDbgVariableRecordGetExpression(LLVMDbgRecordRef Rec) {
+  return wrap(unwrap<DbgVariableRecord>(Rec)->getRawExpression());
+}
+
 unsigned LLVMGetNumArgOperands(LLVMValueRef Instr) {
   if (FuncletPadInst *FPI = dyn_cast<FuncletPadInst>(unwrap(Instr))) {
     return FPI->arg_size();

llvm/tools/llvm-c-test/debuginfo.c

@@ -364,6 +364,43 @@ int llvm_test_dibuilder(void) {
   assert(AddDbgRecordUnderTheRange == NULL);
   (void)AddDbgRecordUnderTheRange;
 
+  // Test that we can read the first debug record.
+  LLVMMetadataRef AddDbgRecordFirstDebugLoc =
+      LLVMDbgRecordGetDebugLoc(AddDbgRecordFirst);
+  (void)AddDbgRecordFirstDebugLoc;
+  assert(LLVMDILocationGetLine(AddDbgRecordFirstDebugLoc) == 43);
+  assert(LLVMDbgRecordGetKind(AddDbgRecordFirst) == LLVMDbgRecordValue);
+  LLVMValueRef AddDbgRecordFirstValue =
+      LLVMDbgVariableRecordGetValue(AddDbgRecordFirst, 0);
+  (void)AddDbgRecordFirstValue;
+  assert(LLVMGetValueKind(AddDbgRecordFirstValue) == LLVMConstantIntValueKind);
+  assert(LLVMConstIntGetZExtValue(AddDbgRecordFirstValue) == 0);
+  LLVMMetadataRef AddDbgRecordFirstVariable =
+      LLVMDbgVariableRecordGetVariable(AddDbgRecordFirst);
+  (void)AddDbgRecordFirstVariable;
+  assert(LLVMGetMetadataKind(AddDbgRecordFirstVariable) ==
+         LLVMDILocalVariableMetadataKind);
+  // TODO: For now, there is no way to get the name.
+  LLVMMetadataRef AddDbgRecordFirstVariableScope =
+      LLVMDIVariableGetScope(AddDbgRecordFirstVariable);
+  (void)AddDbgRecordFirstVariableScope;
+  assert(LLVMGetMetadataKind(AddDbgRecordFirstVariableScope) ==
+         LLVMDILexicalBlockMetadataKind);
+  LLVMMetadataRef AddDbgRecordFirstVariableFile =
+      LLVMDIScopeGetFile(AddDbgRecordFirstVariableScope);
+  (void)AddDbgRecordFirstVariableFile;
+  assert(LLVMGetMetadataKind(AddDbgRecordFirstVariableFile) ==
+         LLVMDIFileMetadataKind);
+  unsigned FileLen = 0;
+  assert(strcmp(LLVMDIFileGetFilename(AddDbgRecordFirstVariableFile, &FileLen),
+                "debuginfo.c") == 0);
+  (void)FileLen;
+  LLVMMetadataRef AddDbgRecordFirstExpr =
+      LLVMDbgVariableRecordGetExpression(AddDbgRecordFirst);
+  assert(LLVMGetMetadataKind(AddDbgRecordFirstExpr) ==
+         LLVMDIExpressionMetadataKind);
+  (void)AddDbgRecordFirstExpr;
+
   char *MStr = LLVMPrintModuleToString(M);
   puts(MStr);
   LLVMDisposeMessage(MStr);