mirror of git://gcc.gnu.org/git/gcc.git
				
				
				
			
		
			
				
	
	
		
			99 lines
		
	
	
		
			2.7 KiB
		
	
	
	
		
			Go
		
	
	
	
			
		
		
	
	
			99 lines
		
	
	
		
			2.7 KiB
		
	
	
	
		
			Go
		
	
	
	
// Copyright 2011 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Package debug contains facilities for programs to debug themselves while
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// they are running.
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package debug
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import (
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	"bytes"
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	"fmt"
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	"io/ioutil"
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	"os"
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	"runtime"
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)
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var (
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	dunno     = []byte("???")
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	centerDot = []byte("·")
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	dot       = []byte(".")
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	slash     = []byte("/")
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)
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// PrintStack prints to standard error the stack trace returned by Stack.
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func PrintStack() {
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	os.Stderr.Write(stack())
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}
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// Stack returns a formatted stack trace of the goroutine that calls it.
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// For each routine, it includes the source line information and PC value,
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// then attempts to discover, for Go functions, the calling function or
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// method and the text of the line containing the invocation.
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//
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// This function is deprecated. Use package runtime's Stack instead.
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func Stack() []byte {
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	return stack()
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}
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// stack implements Stack, skipping 2 frames
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func stack() []byte {
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	buf := new(bytes.Buffer) // the returned data
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	// As we loop, we open files and read them. These variables record the currently
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	// loaded file.
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	var lines [][]byte
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	var lastFile string
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	for i := 2; ; i++ { // Caller we care about is the user, 2 frames up
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		pc, file, line, ok := runtime.Caller(i)
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		if !ok {
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			break
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		}
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		// Print this much at least.  If we can't find the source, it won't show.
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		fmt.Fprintf(buf, "%s:%d (0x%x)\n", file, line, pc)
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		if file != lastFile {
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			data, err := ioutil.ReadFile(file)
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			if err != nil {
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				continue
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			}
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			lines = bytes.Split(data, []byte{'\n'})
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			lastFile = file
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		}
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		line-- // in stack trace, lines are 1-indexed but our array is 0-indexed
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		fmt.Fprintf(buf, "\t%s: %s\n", function(pc), source(lines, line))
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	}
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	return buf.Bytes()
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}
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// source returns a space-trimmed slice of the n'th line.
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func source(lines [][]byte, n int) []byte {
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	if n < 0 || n >= len(lines) {
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		return dunno
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	}
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	return bytes.Trim(lines[n], " \t")
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}
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// function returns, if possible, the name of the function containing the PC.
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func function(pc uintptr) []byte {
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	fn := runtime.FuncForPC(pc)
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	if fn == nil {
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		return dunno
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	}
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	name := []byte(fn.Name())
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	// The name includes the path name to the package, which is unnecessary
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	// since the file name is already included.  Plus, it has center dots.
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	// That is, we see
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	//	runtime/debug.*T·ptrmethod
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	// and want
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	//	*T.ptrmethod
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	// Since the package path might contains dots (e.g. code.google.com/...),
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	// we first remove the path prefix if there is one.
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	if lastslash := bytes.LastIndex(name, slash); lastslash >= 0 {
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		name = name[lastslash+1:]
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	}
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	if period := bytes.Index(name, dot); period >= 0 {
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		name = name[period+1:]
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	}
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	name = bytes.Replace(name, centerDot, dot, -1)
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	return name
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}
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