cmd/link/internal/ld: add dwarf testing helpers
Many tests build a program just to analyze it with dwtest.Examiner. Add
gobuildAndExamine, a helper that returns Examiner directly to reduce
duplication in these tests.
Many tests also lookup the DIE for a specific subprogram, which includes
several verification steps. Package those up in findSubprogramDIE.
Change-Id: I72202ba289ae8389b682be525ff7e6cfbfc00ff3
Reviewed-on: https://go-review.googlesource.com/c/go/+/458196
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Auto-Submit: Michael Pratt <mpratt@google.com>
Run-TryBot: Michael Pratt <mpratt@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
diff --git a/src/cmd/link/internal/ld/dwarf_test.go b/src/cmd/link/internal/ld/dwarf_test.go
index a11541f..e3a2109 100644
--- a/src/cmd/link/internal/ld/dwarf_test.go
+++ b/src/cmd/link/internal/ld/dwarf_test.go
@@ -135,6 +135,45 @@
return &builtFile{f, dst}
}
+// Helper to build a snippet of source for examination with dwtest.Examiner.
+func gobuildAndExamine(t *testing.T, source string, gcflags string) (*dwarf.Data, *dwtest.Examiner) {
+ dir := t.TempDir()
+
+ f := gobuild(t, dir, source, gcflags)
+ defer f.Close()
+
+ d, err := f.DWARF()
+ if err != nil {
+ t.Fatalf("error reading DWARF in program %q: %v", source, err)
+ }
+
+ rdr := d.Reader()
+ ex := &dwtest.Examiner{}
+ if err := ex.Populate(rdr); err != nil {
+ t.Fatalf("error populating DWARF examiner for program %q: %v", source, err)
+ }
+
+ return d, ex
+}
+
+func findSubprogramDIE(t *testing.T, ex *dwtest.Examiner, sym string) *dwarf.Entry {
+ dies := ex.Named(sym)
+ if len(dies) == 0 {
+ t.Fatalf("unable to locate DIE for %s", sym)
+ }
+ if len(dies) != 1 {
+ t.Fatalf("more than one %s DIE: %+v", sym, dies)
+ }
+ die := dies[0]
+
+ // Vet the DIE.
+ if die.Tag != dwarf.TagSubprogram {
+ t.Fatalf("unexpected tag %v on %s DIE", die.Tag, sym)
+ }
+
+ return die
+}
+
func TestEmbeddedStructMarker(t *testing.T) {
t.Parallel()
testenv.MustHaveGoBuild(t)
@@ -341,21 +380,7 @@
prog := fmt.Sprintf("package main\n%s\nfunc main() {\n\nvar i int\ni = i\n}\n", directive)
const iLineOffset = 2
- dir := t.TempDir()
-
- f := gobuild(t, dir, prog, NoOpt)
- defer f.Close()
-
- d, err := f.DWARF()
- if err != nil {
- t.Fatalf("error reading DWARF: %v", err)
- }
-
- rdr := d.Reader()
- ex := dwtest.Examiner{}
- if err := ex.Populate(rdr); err != nil {
- t.Fatalf("error reading DWARF: %v", err)
- }
+ d, ex := gobuildAndExamine(t, prog, NoOpt)
// Locate the main.main DIE
mains := ex.Named("main.main")
@@ -466,44 +491,17 @@
G = x
}
`
- dir := t.TempDir()
-
// Note: this is a build with "-l=4", as opposed to "-l -N". The
// test is intended to verify DWARF that is only generated when
// the inliner is active. We're only going to look at the DWARF for
// main.main, however, hence we build with "-gcflags=-l=4" as opposed
// to "-gcflags=all=-l=4".
- f := gobuild(t, dir, prog, OptInl4)
- defer f.Close()
-
- d, err := f.DWARF()
- if err != nil {
- t.Fatalf("error reading DWARF: %v", err)
- }
+ d, ex := gobuildAndExamine(t, prog, OptInl4)
// The inlined subroutines we expect to visit
expectedInl := []string{"main.cand"}
- rdr := d.Reader()
- ex := dwtest.Examiner{}
- if err := ex.Populate(rdr); err != nil {
- t.Fatalf("error reading DWARF: %v", err)
- }
-
- // 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")
- }
- maindie := mains[0]
-
- // Vet the main.main DIE
- if maindie.Tag != dwarf.TagSubprogram {
- t.Fatalf("unexpected tag %v on main.main DIE", maindie.Tag)
- }
+ maindie := findSubprogramDIE(t, ex, "main.main")
// Walk main's children and pick out the inlined subroutines
mainIdx := ex.IdxFromOffset(maindie.Offset)
@@ -1334,20 +1332,12 @@
t.Fatalf("error parsing DWARF: %v", err)
}
rdr := dw.Reader()
- ex := dwtest.Examiner{}
+ ex := &dwtest.Examiner{}
if err := ex.Populate(rdr); err != nil {
t.Fatalf("error reading DWARF: %v", err)
}
- // 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")
- }
- maindie := mains[0]
+ maindie := findSubprogramDIE(t, ex, "main.main")
// Collect the start/end PC for main.main
lowpc := maindie.Val(dwarf.AttrLowpc).(uint64)
@@ -1556,38 +1546,12 @@
println(v1, v2, v3[0], v4, v5, v6)
}
`
- dir := t.TempDir()
- f := gobuild(t, dir, prog, NoOpt)
- defer f.Close()
+ _, ex := gobuildAndExamine(t, prog, NoOpt)
- d, err := f.DWARF()
- if err != nil {
- t.Fatalf("error reading DWARF: %v", err)
- }
-
- rdr := d.Reader()
- ex := dwtest.Examiner{}
- if err := ex.Populate(rdr); err != nil {
- t.Fatalf("error reading DWARF: %v", err)
- }
-
- // Locate the main.ABC DIE
- abcs := ex.Named("main.ABC")
- if len(abcs) == 0 {
- t.Fatalf("unable to locate DIE for main.ABC")
- }
- if len(abcs) != 1 {
- t.Fatalf("more than one main.ABC DIE")
- }
- abcdie := abcs[0]
-
- // Vet the DIE
- if abcdie.Tag != dwarf.TagSubprogram {
- t.Fatalf("unexpected tag %v on main.ABC DIE", abcdie.Tag)
- }
+ abcdie := findSubprogramDIE(t, ex, "main.ABC")
// Call a helper to collect param info.
- found := processParams(abcdie, &ex)
+ found := processParams(abcdie, ex)
// Make sure we see all of the expected params in the proper
// order, that they have the varparam attr, and the varparam is
@@ -1788,20 +1752,7 @@
}
`
- dir := t.TempDir()
- f := gobuild(t, dir, prog, DefaultOpt)
- defer f.Close()
-
- d, err := f.DWARF()
- if err != nil {
- t.Fatalf("error reading DWARF: %v", err)
- }
-
- rdr := d.Reader()
- ex := dwtest.Examiner{}
- if err := ex.Populate(rdr); err != nil {
- t.Fatalf("error reading DWARF: %v", err)
- }
+ _, ex := gobuildAndExamine(t, prog, DefaultOpt)
testcases := []struct {
tag string
@@ -1828,22 +1779,10 @@
for _, tc := range testcases {
// Locate the proper DIE
which := fmt.Sprintf("main.%s", tc.tag)
- tcs := ex.Named(which)
- if len(tcs) == 0 {
- t.Fatalf("unable to locate DIE for " + which)
- }
- if len(tcs) != 1 {
- t.Fatalf("more than one " + which + " DIE")
- }
- die := tcs[0]
-
- // Vet the DIE
- if die.Tag != dwarf.TagSubprogram {
- t.Fatalf("unexpected tag %v on "+which+" DIE", die.Tag)
- }
+ die := findSubprogramDIE(t, ex, which)
// Examine params for this subprogram.
- foundParams := processParams(die, &ex)
+ foundParams := processParams(die, ex)
if foundParams != tc.expected {
t.Errorf("check failed for testcase %s -- wanted:\n%s\ngot:%s\n",
tc.tag, tc.expected, foundParams)
@@ -1956,29 +1895,18 @@
`
for _, opt := range []string{NoOpt, DefaultOpt} {
- dir := t.TempDir()
- f := gobuild(t, dir, prog, opt)
- defer f.Close()
- defer os.RemoveAll(dir)
+ opt := opt
+ t.Run(opt, func(t *testing.T) {
+ _, ex := gobuildAndExamine(t, prog, opt)
- d, err := f.DWARF()
- if err != nil {
- t.Fatalf("error reading DWARF: %v", err)
- }
-
- rdr := d.Reader()
- ex := dwtest.Examiner{}
- if err := ex.Populate(rdr); err != nil {
- t.Fatalf("error reading DWARF: %v", err)
- }
-
- // Locate the main.zeroSizedVariable DIE
- abcs := ex.Named("zeroSizedVariable")
- if len(abcs) == 0 {
- t.Fatalf("unable to locate DIE for zeroSizedVariable")
- }
- if len(abcs) != 1 {
- t.Fatalf("more than one zeroSizedVariable DIE")
- }
+ // Locate the main.zeroSizedVariable DIE
+ abcs := ex.Named("zeroSizedVariable")
+ if len(abcs) == 0 {
+ t.Fatalf("unable to locate DIE for zeroSizedVariable")
+ }
+ if len(abcs) != 1 {
+ t.Fatalf("more than one zeroSizedVariable DIE")
+ }
+ })
}
}
