Add LLVMGlobalAddDebugInfo to Core.cpp (#148747)

This change allows globals to have multiple metadata attached. The
GlobalSetMetadata function only allows only one and is clobbered if
more metadata is attempted to be added. The addDebugInfo
function calls addMetadata. This is needed because some languages have
global structs containing lots of compiler-generated globals.

Author: demoitem

llvm/include/llvm-c/Core.h

@@ -2694,6 +2694,14 @@ LLVM_C_ABI void LLVMSetAlignment(LLVMValueRef V, unsigned Bytes);
 LLVM_C_ABI void LLVMGlobalSetMetadata(LLVMValueRef Global, unsigned Kind,
                                       LLVMMetadataRef MD);
 
+/**
+ * Adds a metadata attachment.
+ *
+ * @see llvm::GlobalObject::addMetadata()
+ */
+LLVM_C_ABI void LLVMGlobalAddMetadata(LLVMValueRef Global, unsigned Kind,
+                                      LLVMMetadataRef MD);
+
 /**
  * Erases a metadata attachment of the given kind if it exists.
  *
@@ -2708,6 +2716,14 @@ LLVM_C_ABI void LLVMGlobalEraseMetadata(LLVMValueRef Global, unsigned Kind);
  */
 LLVM_C_ABI void LLVMGlobalClearMetadata(LLVMValueRef Global);
 
+/**
+ * Add debuginfo metadata to this global.
+ *
+ * @see llvm::GlobalVariable::addDebugInfo()
+ */
+LLVM_C_ABI void LLVMGlobalAddDebugInfo(LLVMValueRef Global,
+                                       LLVMMetadataRef GVE);
+
 /**
  * Retrieves an array of metadata entries representing the metadata attached to
  * this value. The caller is responsible for freeing this array by calling

llvm/lib/IR/Core.cpp

@@ -2186,6 +2186,11 @@ void LLVMGlobalSetMetadata(LLVMValueRef Global, unsigned Kind,
   unwrap<GlobalObject>(Global)->setMetadata(Kind, unwrap<MDNode>(MD));
 }
 
+void LLVMGlobalAddMetadata(LLVMValueRef Global, unsigned Kind,
+                           LLVMMetadataRef MD) {
+  unwrap<GlobalObject>(Global)->addMetadata(Kind, *unwrap<MDNode>(MD));
+}
+
 void LLVMGlobalEraseMetadata(LLVMValueRef Global, unsigned Kind) {
   unwrap<GlobalObject>(Global)->eraseMetadata(Kind);
 }
@@ -2194,6 +2199,11 @@ void LLVMGlobalClearMetadata(LLVMValueRef Global) {
   unwrap<GlobalObject>(Global)->clearMetadata();
 }
 
+void LLVMGlobalAddDebugInfo(LLVMValueRef Global, LLVMMetadataRef GVE) {
+  unwrap<GlobalVariable>(Global)->addDebugInfo(
+      unwrap<DIGlobalVariableExpression>(GVE));
+}
+
 /*--.. Operations on global variables ......................................--*/
 
 LLVMValueRef LLVMAddGlobal(LLVMModuleRef M, LLVMTypeRef Ty, const char *Name) {

llvm/test/Bindings/llvm-c/add_globaldebuginfo.ll

@@ -0,0 +1,2 @@
+; RUN: llvm-c-test --add-globaldebuginfo < /dev/null
+; This used to trigger an assertion

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

@@ -416,3 +416,40 @@ int llvm_di_type_get_name(void) {
 
   return 0;
 }
+
+int llvm_add_globaldebuginfo(void) {
+  const char *Filename = "debuginfo.c";
+  LLVMModuleRef M = LLVMModuleCreateWithName(Filename);
+  LLVMDIBuilderRef Builder = LLVMCreateDIBuilder(M);
+  LLVMMetadataRef File =
+      LLVMDIBuilderCreateFile(Builder, Filename, strlen(Filename), ".", 1);
+
+  LLVMMetadataRef GlobalVarValueExpr =
+      LLVMDIBuilderCreateConstantValueExpression(Builder, 0);
+  LLVMMetadataRef Int64Ty =
+      LLVMDIBuilderCreateBasicType(Builder, "Int64", 5, 64, 0, LLVMDIFlagZero);
+  LLVMMetadataRef Int64TypeDef = LLVMDIBuilderCreateTypedef(
+      Builder, Int64Ty, "int64_t", 7, File, 42, File, 0);
+
+  LLVMMetadataRef GVE = LLVMDIBuilderCreateGlobalVariableExpression(
+      Builder, File, "global", 6, "", 0, File, 1, Int64TypeDef, true,
+      GlobalVarValueExpr, NULL, 0);
+
+  LLVMTypeRef RecType =
+      LLVMStructCreateNamed(LLVMGetModuleContext(M), "struct");
+  LLVMValueRef Global = LLVMAddGlobal(M, RecType, "global");
+
+  LLVMGlobalAddDebugInfo(Global, GVE);
+  // use AddMetadata to add twice
+  int kindId = LLVMGetMDKindID("dbg", 3);
+  LLVMGlobalAddMetadata(Global, kindId, GVE);
+  size_t numEntries;
+  LLVMValueMetadataEntry *ME = LLVMGlobalCopyAllMetadata(Global, &numEntries);
+  assert(ME != NULL);
+  assert(numEntries == 2);
+
+  LLVMDisposeDIBuilder(Builder);
+  LLVMDisposeModule(M);
+
+  return 0;
+}

llvm/tools/llvm-c-test/llvm-c-test.h

@@ -45,6 +45,7 @@ int llvm_add_named_metadata_operand(void);
 int llvm_set_metadata(void);
 int llvm_replace_md_operand(void);
 int llvm_is_a_value_as_metadata(void);
+int llvm_add_globaldebuginfo(void);
 
 // object.c
 int llvm_object_list_sections(void);

llvm/tools/llvm-c-test/main.c

@@ -101,6 +101,8 @@ int main(int argc, char **argv) {
     return llvm_replace_md_operand();
   } else if (argc == 2 && !strcmp(argv[1], "--is-a-value-as-metadata")) {
     return llvm_is_a_value_as_metadata();
+  } else if (argc == 2 && !strcmp(argv[1], "--add-globaldebuginfo")) {
+    return llvm_add_globaldebuginfo();
   } else if (argc == 2 && !strcmp(argv[1], "--test-function-attributes")) {
     return llvm_test_function_attributes();
   } else if (argc == 2 && !strcmp(argv[1], "--test-callsite-attributes")) {