asm

Documentation

Overview

Asm, typically invoked as “go tool asm”, assembles the source file into an object file named for the basename of the argument source file with a .o suffix. The object file can then be combined with other objects into a package archive.

Command Line

Usage:

go tool asm [flags] file

The specified file must be a Go assembly file. The same assembler is used for all target operating systems and architectures. The GOOS and GOARCH environment variables set the desired target.

Flags:

-D name[=value]
	Predefine symbol name with an optional simple value.
	Can be repeated to define multiple symbols.
-I dir1 -I dir2
	Search for #include files in dir1, dir2, etc,
	after consulting $GOROOT/pkg/$GOOS_$GOARCH.
-S
	Print assembly and machine code.
-V
	Print assembler version and exit.
-debug
	Dump instructions as they are parsed.
-dynlink
	Support references to Go symbols defined in other shared libraries.
-e
	No limit on number of errors reported.
-gensymabis
	Write symbol ABI information to output file. Don't assemble.
-o file
	Write output to file. The default is foo.o for /a/b/c/foo.s.
-p pkgpath
	Set expected package import to pkgpath.
-shared
	Generate code that can be linked into a shared library.
-spectre list
	Enable spectre mitigations in list (all, ret).
-trimpath prefix
	Remove prefix from recorded source file paths.
-v
	Print debug output.

Input language:

The assembler uses mostly the same syntax for all architectures, the main variation having to do with addressing modes. Input is run through a simplified C preprocessor that implements #include, #define, #ifdef/endif, but not #if or ##.

For more information, see https://golang.org/doc/asm.