From 89bab9883341fcf1a3e0e7770b5431710e2c2e4c Mon Sep 17 00:00:00 2001
From: pancake <pancake@nowsecure.com>
Date: Fri, 26 Nov 2021 18:03:15 +0100
Subject: [PATCH] native: implement a working hello world compilation for w64
 (#12577)

---
 cmd/tools/vtest-all.v     |  17 ++++
 vlib/v/gen/native/amd64.v | 102 ++++++++++++++++++++++--
 vlib/v/gen/native/gen.v   |  12 +++
 vlib/v/gen/native/macho.v |   9 ++-
 vlib/v/gen/native/pe.v    | 159 +++++++++++++++++++++++++-------------
 5 files changed, 236 insertions(+), 63 deletions(-)

diff --git a/cmd/tools/vtest-all.v b/cmd/tools/vtest-all.v
index aaf74da119..76ca6ac4fd 100644
--- a/cmd/tools/vtest-all.v
+++ b/cmd/tools/vtest-all.v
@@ -71,6 +71,23 @@ fn get_all_commands() []Command {
 			line: '$vexe run examples/v_script.vsh > /dev/null'
 			okmsg: 'V can run the .VSH script file examples/v_script.vsh'
 		}
+		//
+		res << Command{
+			line: '$vexe -os linux -b native -o hw.linux examples/hello_world.v'
+			okmsg: 'V compiles hello_world.v on the native backend for linux'
+			rmfile: 'hw.linux'
+		}
+		res << Command{
+			line: '$vexe -os macos -b native -o hw.macos examples/hello_world.v'
+			okmsg: 'V compiles hello_world.v on the native backend for macos'
+			rmfile: 'hw.macos'
+		}
+		res << Command{
+			line: '$vexe -os windows -b native -o hw.exe examples/hello_world.v'
+			okmsg: 'V compiles hello_world.v on the native backend for windows'
+			rmfile: 'hw.exe'
+		}
+		//
 		res << Command{
 			line: '$vexe -b js -o hw.js examples/hello_world.v'
 			okmsg: 'V compiles hello_world.v on the JS backend'
diff --git a/vlib/v/gen/native/amd64.v b/vlib/v/gen/native/amd64.v
index a4a32c35ef..cc27eb1bbc 100644
--- a/vlib/v/gen/native/amd64.v
+++ b/vlib/v/gen/native/amd64.v
@@ -204,6 +204,14 @@ fn (mut g Gen) mov64(reg Register, val i64) {
 			g.write8(0xc7)
 			g.write8(0xc1)
 		}
+		.rdx {
+			g.write8(0x48)
+			g.write8(0xc7)
+			g.write8(0xc2)
+			g.write32(i32(int(val)))
+			g.println('mov32 $reg, $val')
+			return
+		}
 		.rbx {
 			g.write8(0x48)
 			g.write8(0xc7)
@@ -427,7 +435,8 @@ pub fn (mut g Gen) allocate_string(s string, opsize int) int {
 	g.strings << s
 	str_pos := g.buf.len + opsize
 	g.str_pos << str_pos
-	return 0
+	g.strs << String{s, str_pos}
+	return str_pos
 }
 
 pub fn (mut g Gen) cld_repne_scasb() {
@@ -484,7 +493,45 @@ pub fn (mut g Gen) gen_print_reg(r Register, n int, fd int) {
 	g.syscall()
 }
 
+pub fn (mut g Gen) apicall(s string) {
+	if g.pref.os != .windows {
+		g.n_error('apicalls are only for windows')
+	}
+	g.write8(0xff)
+	g.write8(0x15)
+	delta := match s {
+		'WriteFile' {
+			-(0xbcc + g.buf.len)
+		}
+		'GetStdHandle' {
+			-(0xbcc + g.buf.len + 8)
+		}
+		'ExitProcess' {
+			-(0xbcc + g.buf.len + 16)
+		}
+		else {
+			0
+		}
+	}
+	g.write32(delta)
+}
+
 pub fn (mut g Gen) gen_print(s string, fd int) {
+	if g.pref.os == .windows {
+		g.sub(.rsp, 0x38)
+		g.mov(.rcx, -11)
+		g.apicall('GetStdHandle')
+		g.mov_reg(.rcx, .rax)
+		// g.mov64(.rdx, g.allocate_string(s, 3))
+		g.lea(.rdx, g.allocate_string(s, 3))
+		g.mov(.r8, s.len) // string length
+		g.write([byte(0x4c), 0x8d, 0x4c, 0x24, 0x20]) // lea r9, [rsp+0x20]
+		g.write([byte(0x48), 0xc7, 0x44, 0x24, 0x20])
+		g.write32(0) // mov qword[rsp+0x20], 0
+		// g.mov(.r9, rsp+0x20)
+		g.apicall('WriteFile')
+		return
+	}
 	//
 	// qq := s + '\n'
 	//
@@ -554,8 +601,21 @@ pub fn (mut g Gen) gen_amd64_exit(expr ast.Expr) {
 			g.n_error('native builtin exit expects a numeric argument')
 		}
 	}
-	g.mov(.eax, g.nsyscall_exit())
-	g.syscall()
+	if g.pref.os == .windows {
+		g.mov_reg(.rcx, .rdi)
+		g.apicall('ExitProcess')
+	} else {
+		g.mov(.eax, g.nsyscall_exit())
+		g.syscall()
+	}
+	g.trap() // should never be reached, just in case
+}
+
+fn (mut g Gen) lea(reg Register, val int) {
+	g.write8(0x48)
+	g.write8(0x8d)
+	g.write8(0x15)
+	g.write32(val)
 }
 
 fn (mut g Gen) mov(reg Register, val int) {
@@ -569,10 +629,15 @@ fn (mut g Gen) mov(reg Register, val int) {
 				return
 			}
 			.rcx {
-				g.write8(0x48)
-				g.write8(0xc7)
-				g.write8(0xc1)
-				g.write32(-1)
+				if val == -1 {
+					g.write8(0x48)
+					g.write8(0xc7)
+					g.write8(0xc1)
+					g.write32(-1)
+				} else {
+					g.write8(0xff)
+					g.write8(0xff) // mov rcx 0xffff5
+				}
 				return
 			}
 			else {
@@ -629,7 +694,16 @@ fn (mut g Gen) mov(reg Register, val int) {
 				g.write8(0xbf)
 			}
 			.rcx {
+				g.write8(0x48)
 				g.write8(0xc7)
+				g.write8(0xc1)
+			}
+			.r8 {
+				g.write8(0x41)
+				g.write8(0xb8)
+			}
+			.r9 {
+				g.write8(0xb9)
 			}
 			.rdx, .edx {
 				g.write8(0xba)
@@ -738,6 +812,14 @@ fn (mut g Gen) mov_reg(a Register, b Register) {
 		g.write8(0x48)
 		g.write8(0x89)
 		g.write8(0xf8)
+	} else if a == .rcx && b == .rdi {
+		g.write8(0x48)
+		g.write8(0x89)
+		g.write8(0xf9)
+	} else if a == .rcx && b == .rax {
+		g.write8(0x48)
+		g.write8(0x89)
+		g.write8(0xc1)
 	} else if a == .rdi && b == .rsi {
 		g.write8(0x48)
 		g.write8(0x89)
@@ -1076,7 +1158,11 @@ fn (mut g Gen) infix_expr(node ast.InfixExpr) {
 
 fn (mut g Gen) trap() {
 	// funnily works on x86 and arm64
-	g.write32(0xcccccccc)
+	if g.pref.arch == .arm64 {
+		g.write32(0xcccccccc)
+	} else {
+		g.write8(0xcc)
+	}
 	g.println('trap')
 }
 
diff --git a/vlib/v/gen/native/gen.v b/vlib/v/gen/native/gen.v
index 7d153c4524..74911f37fe 100644
--- a/vlib/v/gen/native/gen.v
+++ b/vlib/v/gen/native/gen.v
@@ -47,6 +47,12 @@ mut:
 	size_pos             []int
 	nlines               int
 	callpatches          []CallPatch
+	strs                 []String
+}
+
+struct String {
+	str string
+	pos int
 }
 
 struct CallPatch {
@@ -176,6 +182,12 @@ pub fn (g &Gen) pos() i64 {
 	return g.buf.len
 }
 
+fn (mut g Gen) write(bytes []byte) {
+	for _, b in bytes {
+		g.buf << b
+	}
+}
+
 fn (mut g Gen) write8(n int) {
 	// write 1 byte
 	g.buf << byte(n)
diff --git a/vlib/v/gen/native/macho.v b/vlib/v/gen/native/macho.v
index b25bf05a1d..c7aee25b03 100644
--- a/vlib/v/gen/native/macho.v
+++ b/vlib/v/gen/native/macho.v
@@ -395,9 +395,14 @@ fn (mut g Gen) write_symbol(s Symbol) {
 fn (mut g Gen) sym_string_table() int {
 	begin := g.buf.len
 	g.zeroes(1)
-	at := i64(0x100000000)
 	for i, s in g.strings {
-		g.write64_at(at + g.buf.len, int(g.str_pos[i]))
+		pos := g.buf.len - int(g.str_pos[i])
+		if g.pref.os == .windows {
+			g.write32_at(int(g.str_pos[i]), pos - 4) // 0x402028 + pos)
+		} else {
+			baddr := i64(0x100000000)
+			g.write64_at(g.buf.len + baddr, int(g.str_pos[i]))
+		}
 		g.write_string(s)
 		g.write8(0)
 	}
diff --git a/vlib/v/gen/native/pe.v b/vlib/v/gen/native/pe.v
index d23794d1f6..ed42685d09 100644
--- a/vlib/v/gen/native/pe.v
+++ b/vlib/v/gen/native/pe.v
@@ -1,9 +1,16 @@
 module native
 
 enum PeCharacteristics {
-	executable_image = 0x102
+	// 1: relocation info stripped
+	// 2: file is executable
+	// 4: line numbers stripped
+	// 8: local symbols stripped
+	// 20: app can handle > 2GB
+	executable_image = 0x2f
 }
 
+const image_base = i64(0x400000)
+
 enum PeMachine {
 	i386 = 0x14c
 	amd64 = 0x8664
@@ -18,14 +25,14 @@ enum PeHeader {
 pub fn (mut g Gen) write_dos_header() {
 	dos_header := [
 		int(PeHeader.mz),
-		0x90, // usedbytesinthelastpage
-		3, // filesizeinpages
-		0, // numofrelocs
-		2, // header size in paragraph
-		0, // minimum extra paragraphs
-		-1, // maximum extra paragraphs
+		0x80, // bytes on last page of file
+		1, // pages in file
+		0, // relocations
+		4, // header size in paragraph
+		0x10, // minimum extra paragraphs
+		0xffff, // maximum extra paragraphs
 		0, // initial relative ss
-		0xb8, // initial SP
+		0x140, // initial SP
 		0, // checksum
 		0, // IP
 		0, // IP relative CS
@@ -47,14 +54,14 @@ pub fn (mut g Gen) write_dos_header() {
 		0,
 		0,
 		0,
-		0xf8,
+		0x80,
 		0, // address of PE header
 	]
 	for b in dos_header {
 		g.write16(b)
 	}
 	if g.buf.len != 0x40 {
-		// g.warning('Invalid dos header size')
+		g.n_error('Invalid dos header size')
 	}
 }
 
@@ -65,9 +72,46 @@ pub fn (mut g Gen) write_dos_stub() {
 	g.write8(0xba) // richend
 	g.write8(0x0e) // richend
 	// TODO: add a stub for DOS/16, we only run on amd64
-	for g.buf.len < 0xf8 {
-		g.write8(0) // entries
-	}
+	pad_to(mut g.buf, 0x80)
+}
+
+fn (mut g Gen) write_pe_sections() {
+	pad_to(mut g.buf, 0x180)
+	g.write64(0)
+	g.write_string_with_padding('.idata', 8)
+	g.write32(0x89) // 137
+	g.write16(0x1000)
+	g.write32(0x02000000)
+	g.write32(0x02000000)
+	g.zeroes(14)
+	g.write16(64)
+	g.write8(0)
+	g.write8(192)
+	g.write_string_with_padding('.text', 8)
+	g.write32(75)
+	g.write8(0)
+	g.write32(0x20)
+	g.write32(0x00002)
+	g.write32(4)
+	g.write32(0)
+	g.write32(0)
+	g.write32(0x20000000) // 0, 0, 0, 32,
+	g.write([byte(0), 0, 96])
+	g.zeroes(52)
+	g.write([byte(72), 16, 0, 0])
+	g.write([byte(40), 16, 0, 0])
+	g.zeroes(20)
+	g.write([byte(96), 16, 0, 0])
+	g.write32(0)
+	g.write([byte(110), 16, 0, 0])
+	g.write32(0)
+	g.write([byte(125), 16, 0, 0])
+	g.zeroes(12)
+	g.write_string_with_padding('KERNEL32.DLL', 13)
+	g.write_string_with_padding('USER32.DLL', 13)
+	g.write_string_with_padding('ExitProcess', 14)
+	g.write_string_with_padding('GetStdHandle', 15)
+	g.write_string_with_padding('WriteFile', 13)
 }
 
 pub fn (mut g Gen) write_pe_header() {
@@ -75,7 +119,7 @@ pub fn (mut g Gen) write_pe_header() {
 		int(PeHeader.pe),
 		0,
 		int(PeMachine.amd64), // machine
-		1, // number of sections
+		2, // number of sections
 		0,
 		0, // timestamp
 		0,
@@ -83,55 +127,59 @@ pub fn (mut g Gen) write_pe_header() {
 		0, // number of symbols
 		0,
 		0xf0, // 40 // size of optional header
-		int(PeCharacteristics.executable_image), // c
-		// 0 // optional header magic
+		int(PeCharacteristics.executable_image),
 	]
 	for b in pe_header {
 		g.write16(b)
 	}
+
 	// optional here comes here
 	p_opthdr := g.buf.len // should be 0x110
-	if p_opthdr != 0x110 {
-		eprintln('Invalid optdr location')
+	if p_opthdr != 0x98 {
+		eprintln('Invalid optdr location $p_opthdr != 0x98')
 	}
-	g.write16(0x20b) // magic (0x10b=pe32, 0x20b=pe64)
-	g.write8(0xe) // major linker version
-	g.write8(0x1d) // minor linker version
-	g.write32(0x10) // sizeofcode
-	g.write32(0x10) // initial data size
-	g.write32(0) // sizeof sizeof uninit data
+	g.write16(0x20b) // magic (0x10b=pe32, 0x20b=pe32+)
+	g.write8(0x1) // major linker version
+	g.write8(0x49) // minor linker version
+	g.write32(0x200) // sizeofcode
+	g.write32(0x200) // initial data size
+	g.write32(0) // sizeof uninit data
 
-	image_base := i64(0x140000000)
-	g.write32(0x1188) // paddr of map // aligned to 4 bytes // entrypoint
-	g.write32(0x1000) // base of code // aligned to 4 bytes
-	g.write64(image_base) // image base vaddr // va // aligned to 4 bytes
+	g.write32(0x2000) // paddr of map // aligned to 4 bytes // entrypoint
+	g.write32(0x2000) // base of code // aligned to 4 bytes
+	g.write64(native.image_base) // image base vaddr // va // aligned to 4 bytes
 	g.write32(0x1000) // SectionAlignment
 	g.write32(0x200) // FileAlignment
-	g.write16(6) // Major OS Version
+	g.write16(1) // Major OS Version
 	g.write16(0) // Minor OS Version
 	g.write16(0) // major image version
 	g.write16(0) // minor image version
-	g.write16(6) // major subsystem version
+	g.write16(5) // major subsystem version
 	g.write16(0) // minor subsystem version
 
 	g.write32(0) // win32versionvalue
-	g.write32(0x1000) // hdrsize + codelen) // sizeofimage
-	g.write32(0x180) // hdrsize) // sizeofheaders
+	g.write32(0x3000) // hdrsize + codelen) // sizeofimage
+	g.write32(0x200) // hdrsize) // sizeofheaders
 
 	g.write32(0) // checksum
 	g.write16(3) // subsystem // subsystem
 	// g.write16(0x400) // dll characteristics
+	g.write16(0)
+	/*
 	g.write8(0x60) // dll characteristics
 	g.write8(0x81) // dll characteristics
-	g.write64(0x100000) // SizeOfStackReserve
+	*/
+	g.write64(0x1000) // SizeOfStackReserve
 	g.write64(0x1000) // SizeOfStackCommit
-	g.write64(0x100000) // SizeOfHeapReserve
-	g.write64(0x1000) // SizeOfHeapCommit
+	g.write64(0x10000) // SizeOfHeapReserve
+	g.write64(0) // SizeOfHeapCommit
 	g.write32(0) // LoaderFlags
-	g.write32(1) // NumberOfRvaAndSizes
+	g.write32(0x10) // NumberOfRvaAndSizes
 
 	g.write32(0)
 	g.write32(0)
+	g.write32(0x1000)
+	g.write32(0x100) // size of code
 }
 
 fn (mut g Gen) write_pe_section() {
@@ -155,30 +203,35 @@ pub fn (mut g Gen) generate_pe_header() {
 	g.write_dos_header()
 	g.write_dos_stub()
 	g.write_pe_header()
+	g.write_pe_sections()
+
+	pad_to(mut g.buf, 0x400)
 	g.code_start_pos = g.buf.len
 
 	g.call(0x18e)
 	g.ret()
+	g.main_fn_addr = g.buf.len
+}
+
+fn pad_to(mut buf []byte, len int) {
+	for buf.len < len {
+		buf << byte(0)
+	}
 }
 
 pub fn (mut g Gen) generate_pe_footer() {
-	/*
-	// TODO: when proper code is generated, uncomment this
-	codesize := g.buf.len - g.code_start_pos
-	delta := int(g.code_start_pos) // header_size
-	// patch the size depending on the codesize
-	for o in g.size_pos {
-		n := g.read32_at(o)
-		g.write32_at(o, n + delta)
-	}
-	*/
-	for g.buf.len < 0x200 {
-		g.write8(0) // entries
-	}
-
-	g.write_pe_section()
+	g.sym_string_table()
+	pad_to(mut g.buf, 0x600)
 	g.file_size_pos = g.buf.len
-	g.main_fn_addr = g.buf.len
-	g.code_start_pos = g.buf.len
+
+	// patch call main
+	if g.pref.arch == .arm64 {
+		bl_next := u32(0x94000001)
+		g.write32_at(g.code_start_pos, int(bl_next))
+	} else {
+		// +1 is for "e8"
+		// -5 is for "e8 00 00 00 00"
+		g.write32_at(g.code_start_pos + 1, int(g.main_fn_addr - g.code_start_pos) - 5)
+	}
 	g.create_executable()
 }