cmd/link/internal/ld: split varDeclCoords tests

This test set is a bit hard to follow due to trying to test both
variable and function declaration location information.

Now that we have additional helpers to avoid duplication, it isn't too
much work to split them up into individually more understandable tests.

Change-Id: I619ac82ac3b5d00683e22a4a2064e2a5b15e8ce9
Reviewed-on: https://go-review.googlesource.com/c/go/+/458197
Auto-Submit: Michael Pratt <mpratt@google.com>
Run-TryBot: Michael Pratt <mpratt@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>

1 files changed, 108 insertions, 66 deletions

diff --git a/src/cmd/link/internal/ld/dwarf_test.go b/src/cmd/link/internal/ld/dwarf_test.go
index e3a2109445..df2e247508 100644
--- a/src/cmd/link/internal/ld/dwarf_test.go
+++ b/src/cmd/link/internal/ld/dwarf_test.go
@@ -373,94 +373,136 @@ func main() {
 	}
 }
 
-// expectLine is the expected line for main.
-func varDeclCoordsAndSubprogramDeclFile(t *testing.T, testpoint string, expectFile string, expectLine int, directive string) {
+func TestSubprogramDeclFileLine(t *testing.T) {
+	testenv.MustHaveGoBuild(t)
 	t.Parallel()
 
-	prog := fmt.Sprintf("package main\n%s\nfunc main() {\n\nvar i int\ni = i\n}\n", directive)
-	const iLineOffset = 2
-
-	d, ex := gobuildAndExamine(t, prog, NoOpt)
-
-	// Locate the main.main DIE
-	mains := ex.Named("main.main")
-	if len(mains) == 0 {
-		t.Fatalf("unable to locate DIE for main.main")
-	}
-	if len(mains) != 1 {
-		t.Fatalf("more than one main.main DIE")
+	if runtime.GOOS == "plan9" {
+		t.Skip("skipping on plan9; no DWARF symbol table in executables")
 	}
-	maindie := mains[0]
 
-	// Vet the main.main DIE
-	if maindie.Tag != dwarf.TagSubprogram {
-		t.Fatalf("unexpected tag %v on main.main DIE", maindie.Tag)
+	const prog = `package main
+%s
+func main() {}
+`
+	tests := []struct {
+		name string
+		prog string
+		file string
+		line int64
+	}{
+		{
+			name: "normal",
+			prog: fmt.Sprintf(prog, ""),
+			file: "test.go",
+			line: 3,
+		},
+		{
+			name: "line-directive",
+			prog: fmt.Sprintf(prog, "//line /foobar.go:200"),
+			file: "foobar.go",
+			line: 200,
+		},
 	}
+	for _, tc := range tests {
+		tc := tc
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
 
-	// Walk main's children and select variable "i".
-	mainIdx := ex.IdxFromOffset(maindie.Offset)
-	childDies := ex.Children(mainIdx)
-	var iEntry *dwarf.Entry
-	for _, child := range childDies {
-		if child.Tag == dwarf.TagVariable && child.Val(dwarf.AttrName).(string) == "i" {
-			iEntry = child
-			break
-		}
-	}
-	if iEntry == nil {
-		t.Fatalf("didn't find DW_TAG_variable for i in main.main")
-	}
+			d, ex := gobuildAndExamine(t, tc.prog, NoOpt)
 
-	// Verify line/file attributes.
-	line, lineOK := iEntry.Val(dwarf.AttrDeclLine).(int64)
-	if !lineOK {
-		t.Errorf("missing or invalid DW_AT_decl_line for i")
-	}
-	if line != int64(expectLine+iLineOffset) {
-		t.Errorf("DW_AT_decl_line for i is %v, want %d", line, expectLine+iLineOffset)
-	}
+			maindie := findSubprogramDIE(t, ex, "main.main")
 
-	fileIdx, fileIdxOK := maindie.Val(dwarf.AttrDeclFile).(int64)
-	if !fileIdxOK {
-		t.Errorf("missing or invalid DW_AT_decl_file for main")
-	}
-	file, err := ex.FileRef(d, mainIdx, fileIdx)
-	if err != nil {
-		t.Fatalf("FileRef: %v", err)
-	}
-	base := filepath.Base(file)
-	if base != expectFile {
-		t.Errorf("DW_AT_decl_file for main is %v, want %v", base, expectFile)
-	}
+			mainIdx := ex.IdxFromOffset(maindie.Offset)
 
-	line, lineOK = maindie.Val(dwarf.AttrDeclLine).(int64)
-	if !lineOK {
-		t.Errorf("missing or invalid DW_AT_decl_line for main")
-	}
-	if line != int64(expectLine) {
-		t.Errorf("DW_AT_decl_line for main is %v, want %d", line, expectLine)
+			fileIdx, fileIdxOK := maindie.Val(dwarf.AttrDeclFile).(int64)
+			if !fileIdxOK {
+				t.Errorf("missing or invalid DW_AT_decl_file for main")
+			}
+			file, err := ex.FileRef(d, mainIdx, fileIdx)
+			if err != nil {
+				t.Fatalf("FileRef: %v", err)
+			}
+			base := filepath.Base(file)
+			if base != tc.file {
+				t.Errorf("DW_AT_decl_file for main is %v, want %v", base, tc.file)
+			}
+
+			line, lineOK := maindie.Val(dwarf.AttrDeclLine).(int64)
+			if !lineOK {
+				t.Errorf("missing or invalid DW_AT_decl_line for main")
+			}
+			if line != tc.line {
+				t.Errorf("DW_AT_decl_line for main is %v, want %d", line, tc.line)
+			}
+		})
 	}
 }
 
-func TestVarDeclCoordsAndSubrogramDeclFile(t *testing.T) {
+func TestVarDeclLine(t *testing.T) {
 	testenv.MustHaveGoBuild(t)
+	t.Parallel()
 
 	if runtime.GOOS == "plan9" {
 		t.Skip("skipping on plan9; no DWARF symbol table in executables")
 	}
 
-	varDeclCoordsAndSubprogramDeclFile(t, "TestVarDeclCoords", "test.go", 3, "")
+	const prog = `package main
+%s
+func main() {
+
+	var i int
+	i = i
 }
+`
+	tests := []struct {
+		name string
+		prog string
+		line int64
+	}{
+		{
+			name: "normal",
+			prog: fmt.Sprintf(prog, ""),
+			line: 5,
+		},
+		{
+			name: "line-directive",
+			prog: fmt.Sprintf(prog, "//line /foobar.go:200"),
+			line: 202,
+		},
+	}
+	for _, tc := range tests {
+		tc := tc
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
 
-func TestVarDeclCoordsWithLineDirective(t *testing.T) {
-	testenv.MustHaveGoBuild(t)
+			_, ex := gobuildAndExamine(t, tc.prog, NoOpt)
 
-	if runtime.GOOS == "plan9" {
-		t.Skip("skipping on plan9; no DWARF symbol table in executables")
-	}
+			maindie := findSubprogramDIE(t, ex, "main.main")
 
-	varDeclCoordsAndSubprogramDeclFile(t, "TestVarDeclCoordsWithLineDirective",
-		"foobar.go", 200, "//line /foobar.go:200")
+			mainIdx := ex.IdxFromOffset(maindie.Offset)
+			childDies := ex.Children(mainIdx)
+			var iEntry *dwarf.Entry
+			for _, child := range childDies {
+				if child.Tag == dwarf.TagVariable && child.Val(dwarf.AttrName).(string) == "i" {
+					iEntry = child
+					break
+				}
+			}
+			if iEntry == nil {
+				t.Fatalf("didn't find DW_TAG_variable for i in main.main")
+			}
+
+			// Verify line/file attributes.
+			line, lineOK := iEntry.Val(dwarf.AttrDeclLine).(int64)
+			if !lineOK {
+				t.Errorf("missing or invalid DW_AT_decl_line for i")
+			}
+			if line != tc.line {
+				t.Errorf("DW_AT_decl_line for i is %v, want %d", line, tc.line)
+			}
+		})
+	}
 }
 
 func TestInlinedRoutineRecords(t *testing.T) {