1 files changed, 285 insertions, 0 deletions
diff --git a/src/runtime/symtab_test.go b/src/runtime/symtab_test.go
new file mode 100644
index 0000000..cf20ea7
--- /dev/null
+++ b/src/runtime/symtab_test.go
@@ -0,0 +1,285 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package runtime_test
+
+import (
+	"runtime"
+	"strings"
+	"testing"
+	"unsafe"
+)
+
+func TestCaller(t *testing.T) {
+	procs := runtime.GOMAXPROCS(-1)
+	c := make(chan bool, procs)
+	for p := 0; p < procs; p++ {
+		go func() {
+			for i := 0; i < 1000; i++ {
+				testCallerFoo(t)
+			}
+			c <- true
+		}()
+		defer func() {
+			<-c
+		}()
+	}
+}
+
+// These are marked noinline so that we can use FuncForPC
+// in testCallerBar.
+//
+//go:noinline
+func testCallerFoo(t *testing.T) {
+	testCallerBar(t)
+}
+
+//go:noinline
+func testCallerBar(t *testing.T) {
+	for i := 0; i < 2; i++ {
+		pc, file, line, ok := runtime.Caller(i)
+		f := runtime.FuncForPC(pc)
+		if !ok ||
+			!strings.HasSuffix(file, "symtab_test.go") ||
+			(i == 0 && !strings.HasSuffix(f.Name(), "testCallerBar")) ||
+			(i == 1 && !strings.HasSuffix(f.Name(), "testCallerFoo")) ||
+			line < 5 || line > 1000 ||
+			f.Entry() >= pc {
+			t.Errorf("incorrect symbol info %d: %t %d %d %s %s %d",
+				i, ok, f.Entry(), pc, f.Name(), file, line)
+		}
+	}
+}
+
+func lineNumber() int {
+	_, _, line, _ := runtime.Caller(1)
+	return line // return 0 for error
+}
+
+// Do not add/remove lines in this block without updating the line numbers.
+var firstLine = lineNumber() // 0
+var (                        // 1
+	lineVar1             = lineNumber()               // 2
+	lineVar2a, lineVar2b = lineNumber(), lineNumber() // 3
+)                        // 4
+var compLit = []struct { // 5
+	lineA, lineB int // 6
+}{ // 7
+	{ // 8
+		lineNumber(), lineNumber(), // 9
+	}, // 10
+	{ // 11
+		lineNumber(), // 12
+		lineNumber(), // 13
+	}, // 14
+	{ // 15
+		lineB: lineNumber(), // 16
+		lineA: lineNumber(), // 17
+	}, // 18
+}                                     // 19
+var arrayLit = [...]int{lineNumber(), // 20
+	lineNumber(), lineNumber(), // 21
+	lineNumber(), // 22
+}                                  // 23
+var sliceLit = []int{lineNumber(), // 24
+	lineNumber(), lineNumber(), // 25
+	lineNumber(), // 26
+}                         // 27
+var mapLit = map[int]int{ // 28
+	29:           lineNumber(), // 29
+	30:           lineNumber(), // 30
+	lineNumber(): 31,           // 31
+	lineNumber(): 32,           // 32
+}                           // 33
+var intLit = lineNumber() + // 34
+	lineNumber() + // 35
+	lineNumber() // 36
+func trythis() { // 37
+	recordLines(lineNumber(), // 38
+		lineNumber(), // 39
+		lineNumber()) // 40
+}
+
+// Modifications below this line are okay.
+
+var l38, l39, l40 int
+
+func recordLines(a, b, c int) {
+	l38 = a
+	l39 = b
+	l40 = c
+}
+
+func TestLineNumber(t *testing.T) {
+	trythis()
+	for _, test := range []struct {
+		name string
+		val  int
+		want int
+	}{
+		{"firstLine", firstLine, 0},
+		{"lineVar1", lineVar1, 2},
+		{"lineVar2a", lineVar2a, 3},
+		{"lineVar2b", lineVar2b, 3},
+		{"compLit[0].lineA", compLit[0].lineA, 9},
+		{"compLit[0].lineB", compLit[0].lineB, 9},
+		{"compLit[1].lineA", compLit[1].lineA, 12},
+		{"compLit[1].lineB", compLit[1].lineB, 13},
+		{"compLit[2].lineA", compLit[2].lineA, 17},
+		{"compLit[2].lineB", compLit[2].lineB, 16},
+
+		{"arrayLit[0]", arrayLit[0], 20},
+		{"arrayLit[1]", arrayLit[1], 21},
+		{"arrayLit[2]", arrayLit[2], 21},
+		{"arrayLit[3]", arrayLit[3], 22},
+
+		{"sliceLit[0]", sliceLit[0], 24},
+		{"sliceLit[1]", sliceLit[1], 25},
+		{"sliceLit[2]", sliceLit[2], 25},
+		{"sliceLit[3]", sliceLit[3], 26},
+
+		{"mapLit[29]", mapLit[29], 29},
+		{"mapLit[30]", mapLit[30], 30},
+		{"mapLit[31]", mapLit[31+firstLine] + firstLine, 31}, // nb it's the key not the value
+		{"mapLit[32]", mapLit[32+firstLine] + firstLine, 32}, // nb it's the key not the value
+
+		{"intLit", intLit - 2*firstLine, 34 + 35 + 36},
+
+		{"l38", l38, 38},
+		{"l39", l39, 39},
+		{"l40", l40, 40},
+	} {
+		if got := test.val - firstLine; got != test.want {
+			t.Errorf("%s on firstLine+%d want firstLine+%d (firstLine=%d, val=%d)",
+				test.name, got, test.want, firstLine, test.val)
+		}
+	}
+}
+
+func TestNilName(t *testing.T) {
+	defer func() {
+		if ex := recover(); ex != nil {
+			t.Fatalf("expected no nil panic, got=%v", ex)
+		}
+	}()
+	if got := (*runtime.Func)(nil).Name(); got != "" {
+		t.Errorf("Name() = %q, want %q", got, "")
+	}
+}
+
+var dummy int
+
+func inlined() {
+	// Side effect to prevent elimination of this entire function.
+	dummy = 42
+}
+
+// A function with an InlTree. Returns a PC within the function body.
+//
+// No inline to ensure this complete function appears in output.
+//
+//go:noinline
+func tracebackFunc(t *testing.T) uintptr {
+	// This body must be more complex than a single call to inlined to get
+	// an inline tree.
+	inlined()
+	inlined()
+
+	// Acquire a PC in this function.
+	pc, _, _, ok := runtime.Caller(0)
+	if !ok {
+		t.Fatalf("Caller(0) got ok false, want true")
+	}
+
+	return pc
+}
+
+// Test that CallersFrames handles PCs in the alignment region between
+// functions (int 3 on amd64) without crashing.
+//
+// Go will never generate a stack trace containing such an address, as it is
+// not a valid call site. However, the cgo traceback function passed to
+// runtime.SetCgoTraceback may not be completely accurate and may incorrect
+// provide PCs in Go code or the alignment region between functions.
+//
+// Go obviously doesn't easily expose the problematic PCs to running programs,
+// so this test is a bit fragile. Some details:
+//
+//   - tracebackFunc is our target function. We want to get a PC in the
+//     alignment region following this function. This function also has other
+//     functions inlined into it to ensure it has an InlTree (this was the source
+//     of the bug in issue 44971).
+//
+//   - We acquire a PC in tracebackFunc, walking forwards until FuncForPC says
+//     we're in a new function. The last PC of the function according to FuncForPC
+//     should be in the alignment region (assuming the function isn't already
+//     perfectly aligned).
+//
+// This is a regression test for issue 44971.
+func TestFunctionAlignmentTraceback(t *testing.T) {
+	pc := tracebackFunc(t)
+
+	// Double-check we got the right PC.
+	f := runtime.FuncForPC(pc)
+	if !strings.HasSuffix(f.Name(), "tracebackFunc") {
+		t.Fatalf("Caller(0) = %+v, want tracebackFunc", f)
+	}
+
+	// Iterate forward until we find a different function. Back up one
+	// instruction is (hopefully) an alignment instruction.
+	for runtime.FuncForPC(pc) == f {
+		pc++
+	}
+	pc--
+
+	// Is this an alignment region filler instruction? We only check this
+	// on amd64 for simplicity. If this function has no filler, then we may
+	// get a false negative, but will never get a false positive.
+	if runtime.GOARCH == "amd64" {
+		code := *(*uint8)(unsafe.Pointer(pc))
+		if code != 0xcc { // INT $3
+			t.Errorf("PC %v code got %#x want 0xcc", pc, code)
+		}
+	}
+
+	// Finally ensure that Frames.Next doesn't crash when processing this
+	// PC.
+	frames := runtime.CallersFrames([]uintptr{pc})
+	frame, _ := frames.Next()
+	if frame.Func != f {
+		t.Errorf("frames.Next() got %+v want %+v", frame.Func, f)
+	}
+}
+
+func BenchmarkFunc(b *testing.B) {
+	pc, _, _, ok := runtime.Caller(0)
+	if !ok {
+		b.Fatal("failed to look up PC")
+	}
+	f := runtime.FuncForPC(pc)
+	b.Run("Name", func(b *testing.B) {
+		for i := 0; i < b.N; i++ {
+			name := f.Name()
+			if name != "runtime_test.BenchmarkFunc" {
+				b.Fatalf("unexpected name %q", name)
+			}
+		}
+	})
+	b.Run("Entry", func(b *testing.B) {
+		for i := 0; i < b.N; i++ {
+			pc := f.Entry()
+			if pc == 0 {
+				b.Fatal("zero PC")
+			}
+		}
+	})
+	b.Run("FileLine", func(b *testing.B) {
+		for i := 0; i < b.N; i++ {
+			file, line := f.FileLine(pc)
+			if !strings.HasSuffix(file, "symtab_test.go") || line == 0 {
+				b.Fatalf("unexpected file/line %q:%d", file, line)
+			}
+		}
+	})
+}