debug/pe: add symbol support

Add support for processing the COFF symbol table.

R=alex.brainman
CC=golang-dev
https://golang.org/cl/6551045

src/pkg/debug/pe/file.go

diff --git a/src/pkg/debug/pe/file.go b/src/pkg/debug/pe/file.go
index 6b98a5f..c857eca 100644
--- a/src/pkg/debug/pe/file.go
+++ b/src/pkg/debug/pe/file.go
@@ -19,6 +19,7 @@
 type File struct {
 	FileHeader
 	Sections []*Section
+	Symbols  []*Symbol
 
 	closer io.Closer
 }
@@ -49,6 +50,14 @@
 	sr *io.SectionReader
 }
 
+type Symbol struct {
+	Name          string
+	Value         uint32
+	SectionNumber int16
+	Type          uint16
+	StorageClass  uint8
+}
+
 type ImportDirectory struct {
 	OriginalFirstThunk uint32
 	TimeDateStamp      uint32
@@ -138,16 +147,49 @@
 	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.")
 	}
-	// get symbol string table
-	sr.Seek(int64(f.FileHeader.PointerToSymbolTable+18*f.FileHeader.NumberOfSymbols), os.SEEK_SET)
+
+	// Get COFF string table, which is located at the end of the COFF symbol table.
+	sr.Seek(int64(f.FileHeader.PointerToSymbolTable+COFFSymbolSize*f.FileHeader.NumberOfSymbols), os.SEEK_SET)
 	var l uint32
 	if err := binary.Read(sr, binary.LittleEndian, &l); err != nil {
 		return nil, err
 	}
 	ss := make([]byte, l)
-	if _, err := r.ReadAt(ss, int64(f.FileHeader.PointerToSymbolTable+18*f.FileHeader.NumberOfSymbols)); err != nil {
+	if _, err := r.ReadAt(ss, int64(f.FileHeader.PointerToSymbolTable+COFFSymbolSize*f.FileHeader.NumberOfSymbols)); err != nil {
 		return nil, err
 	}
+
+	// Process COFF symbol table.
+	sr.Seek(int64(f.FileHeader.PointerToSymbolTable), os.SEEK_SET)
+	aux := uint8(0)
+	for i := 0; i < int(f.FileHeader.NumberOfSymbols); i++ {
+		cs := new(COFFSymbol)
+		if err := binary.Read(sr, binary.LittleEndian, cs); err != nil {
+			return nil, err
+		}
+		if aux > 0 {
+			aux--
+			continue
+		}
+		var name string
+		if cs.Name[0] == 0 && cs.Name[1] == 0 && cs.Name[2] == 0 && cs.Name[3] == 0 {
+			si := int(binary.LittleEndian.Uint32(cs.Name[4:]))
+			name, _ = getString(ss, si)
+		} else {
+			name = cstring(cs.Name[:])
+		}
+		aux = cs.NumberOfAuxSymbols
+		s := &Symbol{
+			Name:          name,
+			Value:         cs.Value,
+			SectionNumber: cs.SectionNumber,
+			Type:          cs.Type,
+			StorageClass:  cs.StorageClass,
+		}
+		f.Symbols = append(f.Symbols, s)
+	}
+
+	// Process sections.
 	sr.Seek(base, os.SEEK_SET)
 	binary.Read(sr, binary.LittleEndian, &f.FileHeader)
 	sr.Seek(int64(f.FileHeader.SizeOfOptionalHeader), os.SEEK_CUR) //Skip OptionalHeader

src/pkg/debug/pe/file_test.go

diff --git a/src/pkg/debug/pe/file_test.go b/src/pkg/debug/pe/file_test.go
index 2815d72..c0f9fcb 100644
--- a/src/pkg/debug/pe/file_test.go
+++ b/src/pkg/debug/pe/file_test.go
@@ -13,6 +13,7 @@
 	file     string
 	hdr      FileHeader
 	sections []*SectionHeader
+	symbols  []*Symbol
 }
 
 var fileTests = []fileTest{
@@ -33,6 +34,24 @@
 			{".debug_pubtypes", 0, 0, 38, 1370, 1580, 0, 1, 0, 1108344832},
 			{".debug_aranges", 0, 0, 32, 1408, 1590, 0, 2, 0, 1108344832},
 		},
+		[]*Symbol{
+			{".file", 0x0, -2, 0x0, 0x67},
+			{"_main", 0x0, 1, 0x20, 0x2},
+			{".text", 0x0, 1, 0x0, 0x3},
+			{".data", 0x0, 2, 0x0, 0x3},
+			{".bss", 0x0, 3, 0x0, 0x3},
+			{".debug_abbrev", 0x0, 4, 0x0, 0x3},
+			{".debug_info", 0x0, 5, 0x0, 0x3},
+			{".debug_line", 0x0, 6, 0x0, 0x3},
+			{".rdata", 0x0, 7, 0x0, 0x3},
+			{".debug_frame", 0x0, 8, 0x0, 0x3},
+			{".debug_loc", 0x0, 9, 0x0, 0x3},
+			{".debug_pubnames", 0x0, 10, 0x0, 0x3},
+			{".debug_pubtypes", 0x0, 11, 0x0, 0x3},
+			{".debug_aranges", 0x0, 12, 0x0, 0x3},
+			{"___main", 0x0, 0, 0x20, 0x2},
+			{"_puts", 0x0, 0, 0x20, 0x2},
+		},
 	},
 	{
 		"testdata/gcc-386-mingw-exec",
@@ -54,6 +73,7 @@
 			{Name: ".debug_frame", VirtualSize: 0x34, VirtualAddress: 0xe000, Size: 0x200, Offset: 0x3800, PointerToRelocations: 0x0, PointerToLineNumbers: 0x0, NumberOfRelocations: 0x0, NumberOfLineNumbers: 0x0, Characteristics: 0x42300000},
 			{Name: ".debug_loc", VirtualSize: 0x38, VirtualAddress: 0xf000, Size: 0x200, Offset: 0x3a00, PointerToRelocations: 0x0, PointerToLineNumbers: 0x0, NumberOfRelocations: 0x0, NumberOfLineNumbers: 0x0, Characteristics: 0x42100000},
 		},
+		[]*Symbol{},
 	},
 }
 
@@ -86,7 +106,15 @@
 		if tn != fn {
 			t.Errorf("open %s: len(Sections) = %d, want %d", tt.file, fn, tn)
 		}
-
+		for i, have := range f.Symbols {
+			if i >= len(tt.symbols) {
+				break
+			}
+			want := tt.symbols[i]
+			if !reflect.DeepEqual(have, want) {
+				t.Errorf("open %s, symbol %d:\n\thave %#v\n\twant %#v\n", tt.file, i, have, want)
+			}
+		}
 	}
 }
 

src/pkg/debug/pe/pe.go

diff --git a/src/pkg/debug/pe/pe.go b/src/pkg/debug/pe/pe.go
index b3dab73..0606217 100644
--- a/src/pkg/debug/pe/pe.go
+++ b/src/pkg/debug/pe/pe.go
@@ -27,6 +27,17 @@
 	Characteristics      uint32
 }
 
+const COFFSymbolSize = 18
+
+type COFFSymbol struct {
+	Name               [8]uint8
+	Value              uint32
+	SectionNumber      int16
+	Type               uint16
+	StorageClass       uint8
+	NumberOfAuxSymbols uint8
+}
+
 const (
 	IMAGE_FILE_MACHINE_UNKNOWN   = 0x0
 	IMAGE_FILE_MACHINE_AM33      = 0x1d3