Improved section offset calculation

go.mod

@@ -7,4 +7,4 @@ require (
 	git.akyoto.dev/go/color v0.1.1
 )
 
-require golang.org/x/sys v0.24.0 // indirect
+require golang.org/x/sys v0.29.0 // indirect

go.sum

@@ -2,5 +2,5 @@ git.akyoto.dev/go/assert v0.1.3 h1:QwCUbmG4aZYsNk/OuRBz1zWVKmGlDUHhOnnDBfn8Qw8=
 git.akyoto.dev/go/assert v0.1.3/go.mod h1:0GzMaM0eURuDwtGkJJkCsI7r2aUKr+5GmWNTFPgDocM=
 git.akyoto.dev/go/color v0.1.1 h1:mMAoMIwLBPNy7ocRSxdsCFs7onPC3GfDEiJErCneqRE=
 git.akyoto.dev/go/color v0.1.1/go.mod h1:ywOjoD0O0sk6bIn92uAJf7mErlEFCuQInL84y4Lqi3Q=
-golang.org/x/sys v0.24.0 h1:Twjiwq9dn6R1fQcyiK+wQyHWfaz/BJB+YIpzU/Cv3Xg=
+golang.org/x/sys v0.29.0 h1:TPYlXGxvx1MGTn2GiZDhnjPA9wZzZeGKHHmKhHYvgaU=
-golang.org/x/sys v0.24.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/sys v0.29.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=

src/asm/Finalize.go

@@ -8,7 +8,10 @@ import (
 
 	"git.akyoto.dev/cli/q/src/config"
 	"git.akyoto.dev/cli/q/src/dll"
+	"git.akyoto.dev/cli/q/src/elf"
 	"git.akyoto.dev/cli/q/src/fs"
+	"git.akyoto.dev/cli/q/src/macho"
+	"git.akyoto.dev/cli/q/src/pe"
 	"git.akyoto.dev/cli/q/src/sizeof"
 	"git.akyoto.dev/cli/q/src/x64"
 )
@@ -370,21 +373,40 @@ restart:
 		}
 	}
 
+	headerEnd := Address(0)
+
+	switch config.TargetOS {
+	case "linux":
+		headerEnd = elf.HeaderEnd
+	case "macos":
+		headerEnd = macho.HeaderEnd
+	case "windows":
+		headerEnd = pe.HeaderEnd
+	}
+
+	codeStart, _ := fs.Align(headerEnd, config.Align)
+	dataStart, _ := fs.Align(codeStart+Address(len(code)), config.Align)
 	data, dataLabels = a.Data.Finalize()
-	dataStart := config.BaseAddress + config.CodeOffset + len(code)
-	dataStart, _ = fs.Align(dataStart, config.Align)
 
 	for _, pointer := range dataPointers {
-		address := Address(dataStart) + pointer.Resolve()
+		address := config.BaseAddress + Address(dataStart) + pointer.Resolve()
 		slice := code[pointer.Position : pointer.Position+4]
 		binary.LittleEndian.PutUint32(slice, uint32(address))
 	}
 
-	for _, pointer := range dllPointers {
+	if config.TargetOS == "windows" {
-		destination := Address(0x3000) + pointer.Resolve()
+		if len(data) == 0 {
-		address := destination - Address(config.CodeOffset+pointer.Position+Address(pointer.Size))
+			data = []byte{0}
-		slice := code[pointer.Position : pointer.Position+4]
+		}
-		binary.LittleEndian.PutUint32(slice, uint32(address))
+
+		importsStart, _ := fs.Align(dataStart+Address(len(data)), config.Align)
+
+		for _, pointer := range dllPointers {
+			destination := Address(importsStart) + pointer.Resolve()
+			delta := destination - Address(codeStart+pointer.Position+Address(pointer.Size))
+			slice := code[pointer.Position : pointer.Position+4]
+			binary.LittleEndian.PutUint32(slice, uint32(delta))
+		}
 	}
 
 	return code, data

src/config/config.go

@@ -9,11 +9,8 @@ const (
 	// The base address is the virtual address for our ELF file.
 	BaseAddress = 0x40 * MinAddress
 
-	// Align decides the alignment of the sections and it must be a multiple of the page size.
+	// Align is the alignment of the sections and it must be a multiple of the page size.
 	Align = 0x1000
-
-	// The code offset is the offset of the executable machine code within the file.
-	CodeOffset = Align
 )
 
 var (

src/elf/ELF.go

@@ -9,6 +9,8 @@ import (
 	"git.akyoto.dev/cli/q/src/fs"
 )
 
+const HeaderEnd = HeaderSize + ProgramHeaderSize*2
+
 // ELF represents an ELF file.
 type ELF struct {
 	Header
@@ -18,8 +20,6 @@ type ELF struct {
 
 // Write writes the ELF64 format to the given writer.
 func Write(writer io.Writer, code []byte, data []byte) {
-	const HeaderEnd = HeaderSize + ProgramHeaderSize*2
-
 	var (
 		codeStart, codePadding = fs.Align(HeaderEnd, config.Align)
 		dataStart, dataPadding = fs.Align(codeStart+len(code), config.Align)
@@ -36,7 +36,7 @@ func Write(writer io.Writer, code []byte, data []byte) {
 			Type:                        TypeExecutable,
 			Architecture:                ArchitectureAMD64,
 			FileVersion:                 1,
-			EntryPointInMemory:          config.BaseAddress + config.CodeOffset,
+			EntryPointInMemory:          int64(config.BaseAddress + codeStart),
 			ProgramHeaderOffset:         HeaderSize,
 			SectionHeaderOffset:         0,
 			Flags:                       0,
@@ -50,9 +50,9 @@ func Write(writer io.Writer, code []byte, data []byte) {
 		CodeHeader: ProgramHeader{
 			Type:            ProgramTypeLOAD,
 			Flags:           ProgramFlagsExecutable | ProgramFlagsReadable,
-			Offset:          config.CodeOffset,
+			Offset:          int64(codeStart),
-			VirtualAddress:  config.BaseAddress + config.CodeOffset,
+			VirtualAddress:  int64(config.BaseAddress + codeStart),
-			PhysicalAddress: config.BaseAddress + config.CodeOffset,
+			PhysicalAddress: int64(config.BaseAddress + codeStart),
 			SizeInFile:      int64(len(code)),
 			SizeInMemory:    int64(len(code)),
 			Align:           config.Align,

src/macho/MachO.go

@@ -9,6 +9,11 @@ import (
 	"git.akyoto.dev/cli/q/src/fs"
 )
 
+const (
+	SizeCommands = Segment64Size*3 + ThreadSize
+	HeaderEnd    = HeaderSize + SizeCommands
+)
+
 // MachO is the executable format used on MacOS.
 type MachO struct {
 	Header
@@ -20,11 +25,6 @@ type MachO struct {
 
 // Write writes the Mach-O format to the given writer.
 func Write(writer io.Writer, code []byte, data []byte) {
-	const (
-		SizeCommands = Segment64Size*3 + ThreadSize
-		HeaderEnd    = HeaderSize + SizeCommands
-	)
-
 	var (
 		codeStart, codePadding = fs.Align(HeaderEnd, config.Align)
 		dataStart, dataPadding = fs.Align(codeStart+len(code), config.Align)
@@ -102,7 +102,7 @@ func Write(writer io.Writer, code []byte, data []byte) {
 				0, 0,
 				0, 0,
 				0, 0,
-				config.BaseAddress + config.CodeOffset, 0,
+				uint32(config.BaseAddress + codeStart), 0,
 				0, 0,
 				0, 0,
 				0, 0,

src/pe/EXE.go

@@ -10,6 +10,11 @@ import (
 	"git.akyoto.dev/cli/q/src/fs"
 )
 
+const (
+	NumSections = 3
+	HeaderEnd   = DOSHeaderSize + NTHeaderSize + OptionalHeader64Size + SectionHeaderSize*NumSections
+)
+
 // EXE is the portable executable format used on Windows.
 type EXE struct {
 	DOSHeader
@@ -20,12 +25,6 @@ type EXE struct {
 
 // Write writes the EXE file to the given writer.
 func Write(writer io.Writer, code []byte, data []byte, dlls dll.List) {
-	if len(data) == 0 {
-		data = []byte{0}
-	}
-
-	NumSections := 3
-	HeaderEnd := DOSHeaderSize + NTHeaderSize + OptionalHeader64Size + SectionHeaderSize*NumSections
 	codeStart, codePadding := fs.Align(HeaderEnd, config.Align)
 	dataStart, dataPadding := fs.Align(codeStart+len(code), config.Align)
 	importsStart, importsPadding := fs.Align(dataStart+len(data), config.Align)
@@ -115,8 +114,8 @@ func Write(writer io.Writer, code []byte, data []byte, dlls dll.List) {
 			SizeOfCode:                  uint32(len(code)),
 			SizeOfInitializedData:       0,
 			SizeOfUninitializedData:     0,
-			AddressOfEntryPoint:         config.CodeOffset,
+			AddressOfEntryPoint:         uint32(codeStart),
-			BaseOfCode:                  config.CodeOffset,
+			BaseOfCode:                  uint32(codeStart),
 			ImageBase:                   config.BaseAddress,
 			SectionAlignment:            config.Align, // power of 2, must be greater than or equal to FileAlignment
 			FileAlignment:               config.Align, // power of 2
@@ -128,7 +127,7 @@ func Write(writer io.Writer, code []byte, data []byte, dlls dll.List) {
 			MinorSubsystemVersion:       0,
 			Win32VersionValue:           0,
 			SizeOfImage:                 uint32(imageSize),
-			SizeOfHeaders:               config.CodeOffset, // section bodies begin here
+			SizeOfHeaders:               uint32(codeStart), // section bodies begin here
 			CheckSum:                    0,
 			Subsystem:                   uint16(subSystem),
 			DllCharacteristics:          IMAGE_DLLCHARACTERISTICS_HIGH_ENTROPY_VA | IMAGE_DLLCHARACTERISTICS_NX_COMPAT | IMAGE_DLLCHARACTERISTICS_TERMINAL_SERVER_AWARE, // IMAGE_DLLCHARACTERISTICS_DYNAMIC_BASE
@@ -161,9 +160,9 @@ func Write(writer io.Writer, code []byte, data []byte, dlls dll.List) {
 			{
 				Name:            [8]byte{'.', 't', 'e', 'x', 't'},
 				VirtualSize:     uint32(len(code)),
-				VirtualAddress:  config.CodeOffset,
+				VirtualAddress:  uint32(codeStart),
 				RawSize:         uint32(len(code)), // must be a multiple of FileAlignment
-				RawAddress:      config.CodeOffset, // must be a multiple of FileAlignment
+				RawAddress:      uint32(codeStart), // must be a multiple of FileAlignment
 				Characteristics: IMAGE_SCN_CNT_CODE | IMAGE_SCN_MEM_EXECUTE | IMAGE_SCN_MEM_READ,
 			},
 			{