README
¶
Go2asm converts the Go compiler's -S output to equivalent assembler source
files.
Usage:
go2asm [-s symregexp] [file]
Go2asm reads the compiler's -S output from file (default standard input),
converting it to equivalent assembler input. If the -s option is present,
go2asm only converts symbols with names matching the regular expression.
Example
To extract the assembly for the function math.IsNaN:
$ go build -a -v -gcflags -S math 2>&1 | go2asm -s math.IsNaN
#include "funcdata.h"
TEXT math·IsNaN(SB), $0-16 // /Users/rsc/go/src/math/bits.go:31
NO_LOCAL_POINTERS
// FUNCDATA $0, gclocals·f207267fbf96a0178e8758c6e3e0ce28(SB) (args)
// FUNCDATA $1, gclocals·33cdeccccebe80329f1fdbee7f5874cb(SB) (no locals)
MOVSD f+0(FP), X0 // bits.go:36
UCOMISD X0, X0
SETNE CL
SETPS AL
ORL AX, CX
MOVB CL, is+8(FP)
RET
$
Or to extract the assembly for a test program:
$ cat /tmp/x.go
package p
func f(x int) (y int) {
return x
}
$ go tool compile -S /tmp/x.go | go2asm
#include "funcdata.h"
TEXT ·f(SB), $0-16 // /tmp/x.go:3
NO_LOCAL_POINTERS
// FUNCDATA $0, gclocals·f207267fbf96a0178e8758c6e3e0ce28(SB) (args)
// FUNCDATA $1, gclocals·33cdeccccebe80329f1fdbee7f5874cb(SB) (no locals)
MOVQ $-3689348814741910323, AX // x.go:4
MOVQ x+0(FP), CX
IMULQ CX
ADDQ CX, DX
SARQ $3, DX
SARQ $63, CX
SUBQ CX, DX
MOVQ DX, y+8(FP)
RET
$
Bugs
Go2asm only handles amd64 assembler.
Data symbols are not implemented.
Documentation
¶
Overview ¶
Go2asm converts the Go compiler's -S output to equivalent assembler source files.
Usage:
go2asm [-s symregexp] [file]
Go2asm reads the compiler's -S output from file (default standard input), converting it to equivalent assembler input. If the -s option is present, go2asm only converts symbols with names matching the regular expression.
Example ¶
Extract the assembly for a test program:
$ cat /tmp/x.go
package p
func f(x int) (y int) {
return x / 10
}
$ go tool compile -S /tmp/x.go | go2asm
#include "funcdata.h"
TEXT ·f(SB), $0-16 // /tmp/x.go:3
NO_LOCAL_POINTERS
// FUNCDATA $0, gclocals·f207267fbf96a0178e8758c6e3e0ce28(SB) (args)
// FUNCDATA $1, gclocals·33cdeccccebe80329f1fdbee7f5874cb(SB) (no locals)
MOVQ $-3689348814741910323, AX // x.go:4
MOVQ x+0(FP), CX
IMULQ CX
ADDQ CX, DX
SARQ $3, DX
SARQ $63, CX
SUBQ CX, DX
MOVQ DX, y+8(FP)
RET
$
Extract the assembly for the function math.IsInf:
$ go build -a -v -gcflags -S math 2>&1 | go2asm -s math.IsInf TEXT math·IsInf(SB), $0-24 // /Users/rsc/go/src/math/bits.go:43 NO_LOCAL_POINTERS // FUNCDATA $0, gclocals·54241e171da8af6ae173d69da0236748(SB) (args) // FUNCDATA $1, gclocals·33cdeccccebe80329f1fdbee7f5874cb(SB) (no locals) MOVQ sign+8(FP), AX // bits.go:48 TESTQ AX, AX JLT pc66 MOVSD f+0(FP), X0 MOVSD $(1.7976931348623157e+308), X1 UCOMISD X1, X0 JLS pc40 MOVL $1, AX pc35: MOVB AL, _r2+16(FP) RET pc40: TESTQ AX, AX pc43: JGT pc62 MOVSD $(-1.7976931348623157e+308), X1 UCOMISD X0, X1 SETHI AL JMP pc35 pc62: MOVL $0, AX JMP pc35 pc66: MOVSD f+0(FP), X0 JMP pc43 $
Bugs ¶
Go2asm only handles amd64 assembler.
Data symbols are not implemented.
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