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Fix asm warning (label name 0 or 1 is prohibited) #104

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Jul 14, 2024
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Fix asm warning (label name 0 or 1 is prohibited) #104

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40 changes: 20 additions & 20 deletions basm-std/src/platform/codegen.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -63,16 +63,16 @@ pub unsafe extern "win64" fn _basm_start() -> ! {
asm!(
"clc", // CF=0 (running without loader) / CF=1 (running with loader)
"mov rbx, rcx", // Save PLATFORM_DATA table
"jnc 1f",
"jnc 2f",
"test rbx, rbx",
"jz 1f",
"jmp 2f",
"1:",
"jz 2f",
"jmp 3f",
"2:",
"sub rsp, 72", // 16 + 72 + 8 = 96 = 16*6 -> stack alignment preserved
"push 3", // env_flags = 3 (ENV_FLAGS_LINUX_STYLE_CHKSTK | ENV_FLAGS_NATIVE)
"push 2", // env_id = 2 (ENV_ID_LINUX)
"lea rbx, [rsp]", // rbx = PLATFORM_DATA table
"2:",
"3:",
"push rcx", // short form of "sub rsp, 8"
"lea rdi, [rip + __ehdr_start]",
"lea rsi, [rip + _DYNAMIC]",
Expand Down Expand Up @@ -127,7 +127,7 @@ pub unsafe extern "win64" fn _basm_start() -> ! {
"clc", // CF=0 (running without loader) / CF=1 (running with loader)
"enter 64, 0", // 64 = 88 - 32 (tables) + 8 (alignment)
"mov rbx, rcx", // save rcx as rbx is non-volatile (callee-saved)
"jc 1f",
"jc 2f",
"call {3}",
"lea rdi, [rip+{4}]",
"push rdi", // GetProcAddress
Expand All @@ -136,16 +136,16 @@ pub unsafe extern "win64" fn _basm_start() -> ! {
"push 1", // env_id = 1 (ENV_ID_WINDOWS)
"mov rbx, rsp", // rbx = PLATFORM_DATA table
"sub rsp, 32",
"jmp 2f",
"1:",
"jmp 3f",
"2:",
"lea rdi, [rip + __ImageBase]", // In-memory ImageBase (cf. Preferred ImageBase is set to 0x0 by static-pie-pe2bin.py)
"mov esi, 0x12345678", // [replaced by static-pie-pe2bin.py] Offset of relocation table (relative to the in-memory ImageBase)
"mov edx, 0x12345678", // [replaced by static-pie-pe2bin.py] Size of relocation table (relative to the in-memory ImageBase)
"mov QWORD PTR [rbx + 32], rdi", // overwrite ptr_alloc_rwx with in-memory ImageBase
"call {0}",
"2:",
"3:",
"bt QWORD PTR [rbx + 8], 0",
"jnc 3f",
"jnc 4f",
// BEGIN Linux patch
// Linux ABI requires us to actually move the stack pointer
// `before' accessing the yet-to-be-committed stack pages.
Expand All @@ -158,7 +158,7 @@ pub unsafe extern "win64" fn _basm_start() -> ! {
"mov BYTE PTR [rip + {5}], 0xc3",
"mov BYTE PTR [rip + {6}], 0xc3",
// END Linux patch
"3:",
"4:",
"mov rcx, rbx",
"call {1}",
"leave",
Expand Down Expand Up @@ -198,23 +198,23 @@ pub unsafe extern "cdecl" fn _basm_start() -> ! {
// on the 16-byte boundary BEFORE `call` instruction
asm!(
"clc", // CF=0 (running without loader) / CF=1 (running with loader)
"jc 1f",
"jc 2f",
"sub esp, 44", // 44 = 40 + 4; PLATFORM_DATA ptr (4 bytes, pushed later) + PLATFORM_DATA (40 (+ 16 = 56 bytes)) + alignment (4 bytes wasted)
"push 0", // zero upper dword
"push 3", // env_flags = 3 (ENV_FLAGS_LINUX_STYLE_CHKSTK | ENV_FLAGS_NATIVE)
"push 0", // zero upper dword
"push 2", // env_id = 2 (ENV_ID_LINUX)
"mov edx, esp", // edx = PLATFORM_DATA table
"jmp 2f",
"1:",
"jmp 3f",
"2:",
"mov edx, DWORD PTR [esp + 4]", // edx = PLATFORM_DATA table
"push ebp",
"mov ebp, esp",
"and esp, 0xFFFFFFF0",
"sub esp, 12",
"2:",
"call 3f",
"3:",
"call 4f",
"4:",
"pop ecx", // ecx = _basm_start + 36 (obtained by counting the opcode size in bytes)
"push edx", // [esp + 0] = PLATFORM_DATA table
"call {2}", // eax = offset of _basm_start from the image base
Expand Down Expand Up @@ -296,14 +296,14 @@ pub unsafe extern "win64" fn __chkstk() -> ! {
"push rax",
"cmp rax, 4096",
"lea rcx, QWORD PTR [rsp + 24]",
"jb 1f",
"2:",
"jb 2f",
"3:",
"sub rcx, 4096",
"test DWORD PTR [rcx], ecx", // just touches the memory address; no meaning in itself
"sub rax, 4096",
"cmp rax, 4096",
"ja 2b",
"1:",
"ja 3b",
"2:",
"sub rcx, rax",
"test DWORD PTR [rcx], ecx", // just touches the memory address; no meaning in itself
"pop rax",
Expand Down