Go binding: Add GetCurrentDebugLocation to obtain debug location from builder

Summary:

Currently Go binding only has SetCurrentDebugLocation method.
I added GetCurrentDebugLocation method to IRBuilder instance.

I added this because I want to save current debug location, change debug location temporary and restore the saved one finally.
This is useful when source location jumps and goes back after while LLVM IR generation.

I also added tests for this to ir_test.go.
I confirmed that all test passed with this patch based on r298890

Patch by Ryuichi Hayashida!

Differential Revision: https://reviews.llvm.org/D31415

llvm-svn: 299185

bindings/go/llvm/IRBindings.cpp

@@ -14,6 +14,7 @@
 #include "IRBindings.h"
 #include "llvm/IR/Attributes.h"
 #include "llvm/IR/DebugLoc.h"
+#include "llvm/IR/DebugInfoMetadata.h"
 #include "llvm/IR/Function.h"
 #include "llvm/IR/IRBuilder.h"
 #include "llvm/IR/LLVMContext.h"
@@ -71,6 +72,18 @@ void LLVMSetCurrentDebugLocation2(LLVMBuilderRef Bref, unsigned Line,
                     InlinedAt ? unwrap<MDNode>(InlinedAt) : nullptr));
 }
 
+LLVMDebugLocMetadata LLVMGetCurrentDebugLocation2(LLVMBuilderRef Bref) {
+  const auto& Loc = unwrap(Bref)->getCurrentDebugLocation();
+  const auto* InlinedAt = Loc.getInlinedAt();
+  const LLVMDebugLocMetadata md{
+    Loc.getLine(),
+    Loc.getCol(),
+    wrap(Loc.getScope()),
+    InlinedAt == nullptr ? nullptr : wrap(InlinedAt->getRawInlinedAt()),
+  };
+  return md;
+}
+
 void LLVMSetSubprogram(LLVMValueRef Func, LLVMMetadataRef SP) {
   unwrap<Function>(Func)->setSubprogram(unwrap<DISubprogram>(SP));
 }

bindings/go/llvm/IRBindings.h

@@ -27,6 +27,12 @@ extern "C" {
 #endif
 
 typedef struct LLVMOpaqueMetadata *LLVMMetadataRef;
+struct LLVMDebugLocMetadata{
+    unsigned Line;
+    unsigned Col;
+    LLVMMetadataRef Scope;
+    LLVMMetadataRef InlinedAt;
+};
 
 LLVMMetadataRef LLVMConstantAsMetadata(LLVMValueRef Val);
 
@@ -46,6 +52,8 @@ void LLVMSetCurrentDebugLocation2(LLVMBuilderRef Bref, unsigned Line,
                                   unsigned Col, LLVMMetadataRef Scope,
                                   LLVMMetadataRef InlinedAt);
 
+struct LLVMDebugLocMetadata LLVMGetCurrentDebugLocation2(LLVMBuilderRef Bref);
+
 void LLVMSetSubprogram(LLVMValueRef Fn, LLVMMetadataRef SP);
 
 #ifdef __cplusplus

bindings/go/llvm/ir.go

@@ -1226,9 +1226,23 @@ func (b Builder) InsertWithName(instr Value, name string) {
 func (b Builder) Dispose() { C.LLVMDisposeBuilder(b.C) }
 
 // Metadata
+type DebugLoc struct {
+	Line, Col      uint
+	Scope          Metadata
+	InlinedAt      Metadata
+}
 func (b Builder) SetCurrentDebugLocation(line, col uint, scope, inlinedAt Metadata) {
 	C.LLVMSetCurrentDebugLocation2(b.C, C.unsigned(line), C.unsigned(col), scope.C, inlinedAt.C)
 }
+// Get current debug location. Please do not call this function until setting debug location with SetCurrentDebugLocation()
+func (b Builder) GetCurrentDebugLocation() (loc DebugLoc) {
+	md := C.LLVMGetCurrentDebugLocation2(b.C)
+	loc.Line = uint(md.Line)
+	loc.Col = uint(md.Col)
+	loc.Scope = Metadata{C: md.Scope}
+	loc.InlinedAt = Metadata{C: md.InlinedAt}
+	return
+}
 func (b Builder) SetInstDebugLocation(v Value) { C.LLVMSetInstDebugLocation(b.C, v.C) }
 func (b Builder) InsertDeclare(module Module, storage Value, md Value) Value {
 	f := module.NamedFunction("llvm.dbg.declare")

bindings/go/llvm/ir_test.go

@@ -95,3 +95,42 @@ func TestAttributes(t *testing.T) {
 		testAttribute(t, name)
 	}
 }
+
+func TestDebugLoc(t *testing.T) {
+	mod := NewModule("")
+	defer mod.Dispose()
+
+	ctx := mod.Context()
+
+	b := ctx.NewBuilder()
+	defer b.Dispose()
+
+	d := NewDIBuilder(mod)
+	defer func() {
+		d.Destroy()
+	}()
+	file := d.CreateFile("dummy_file", "dummy_dir")
+	voidInfo := d.CreateBasicType(DIBasicType{Name: "void"})
+	typeInfo := d.CreateSubroutineType(DISubroutineType{file, []Metadata{voidInfo}})
+	scope := d.CreateFunction(file, DIFunction{
+		Name:         "foo",
+		LinkageName:  "foo",
+		Line:         10,
+		ScopeLine:    10,
+		Type:         typeInfo,
+		File:         file,
+		IsDefinition: true,
+	})
+
+	b.SetCurrentDebugLocation(10, 20, scope, Metadata{})
+	loc := b.GetCurrentDebugLocation()
+	if loc.Line != 10 {
+		t.Errorf("Got line %d, though wanted 10", loc.Line)
+	}
+	if loc.Col != 20 {
+		t.Errorf("Got column %d, though wanted 20", loc.Col)
+	}
+	if loc.Scope.C != scope.C {
+		t.Errorf("Got metadata %v as scope, though wanted %v", loc.Scope.C, scope.C)
+	}
+}