debug/pe: better error messages

Updates #15345

Change-Id: Iae35d3e378cbc8157ba1ff91e4971ed4515a5e5c
Reviewed-on: https://go-review.googlesource.com/22394
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Run-TryBot: Alex Brainman <alex.brainman@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

diff --git a/src/debug/pe/file.go b/src/debug/pe/file.go
index abc33dfea89a73ce9dae69de0f3a52a4b41007e3..1cd84d5727761e482518b0566138d9051bd1312f 100644 (file)
--- a/src/debug/pe/file.go
+++ b/src/debug/pe/file.go
@@ -8,7 +8,6 @@ package pe
 import (
        "debug/dwarf"
        "encoding/binary"
-       "errors"
        "fmt"
        "io"
        "os"
@@ -58,6 +57,8 @@ var (
        sizeofOptionalHeader64 = uint16(binary.Size(OptionalHeader64{}))
 )
 
+// TODO(brainman): add Load function, as a replacement for NewFile, that does not call removeAuxSymbols (for performance)
+
 // NewFile creates a new File for accessing a PE binary in an underlying reader.
 func NewFile(r io.ReaderAt) (*File, error) {
        f := new(File)
@@ -73,7 +74,7 @@ func NewFile(r io.ReaderAt) (*File, error) {
                var sign [4]byte
                r.ReadAt(sign[:], signoff)
                if !(sign[0] == 'P' && sign[1] == 'E' && sign[2] == 0 && sign[3] == 0) {
-                       return nil, errors.New("Invalid PE File Format.")
+                       return nil, fmt.Errorf("Invalid PE COFF file signature of %v.", sign)
                }
                base = signoff + 4
        } else {
@@ -83,8 +84,10 @@ func NewFile(r io.ReaderAt) (*File, error) {
        if err := binary.Read(sr, binary.LittleEndian, &f.FileHeader); err != nil {
                return nil, err
        }
-       if f.FileHeader.Machine != IMAGE_FILE_MACHINE_UNKNOWN && f.FileHeader.Machine != IMAGE_FILE_MACHINE_AMD64 && f.FileHeader.Machine != IMAGE_FILE_MACHINE_I386 {
-               return nil, errors.New("Invalid PE File Format.")
+       switch f.FileHeader.Machine {
+       case IMAGE_FILE_MACHINE_UNKNOWN, IMAGE_FILE_MACHINE_AMD64, IMAGE_FILE_MACHINE_I386:
+       default:
+               return nil, fmt.Errorf("Unrecognised COFF file header machine value of 0x%x.", f.FileHeader.Machine)
        }
 
        var err error