ISSUE.md

Posted as issue http://golang.org/issue/25617

What version of Go are you using (go version)?

go version go1.10.2 darwin/amd64

Does this issue reproduce with the latest release?

Yes, confirmed on 1.9.2 and 1.10.2. Not tested on master.

What operating system and processor architecture are you using (go env)?

GOARCH="amd64"
GOBIN=""
GOCACHE="/Users/michaelmcloughlin/Library/Caches/go-build"
GOEXE=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GOOS="darwin"
GOPATH="/Users/michaelmcloughlin/gocode"
GORACE=""
GOROOT="/usr/local/Cellar/go/1.10.2/libexec"
GOTMPDIR=""
GOTOOLDIR="/usr/local/Cellar/go/1.10.2/libexec/pkg/tool/darwin_amd64"
GCCGO="gccgo"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/var/folders/p5/84p384bs42v7pbgfx0db9gq80000gn/T/go-build505202882=/tmp/go-build -gno-record-gcc-switches -fno-common"

What did you do?

Compiled package with assembly code using PDEPQ. Viewed resulting assembly with go tool objdump.

Gist https://gist.github.com/mmcloughlin/b5bf1bcc7f31222ff2bc510f2777cd79 is a minimal example.

What did you expect to see?

Expect go tool objdump to show the PDEPQ instruction.

What did you see instead?

Output from objdump.sh script is as follows. The objdump tool does not recognize PDEPQ, and instead parses it as a sequence of instructions. Note that LLVM objdump correctly identifies the instruction.

+ go version
go version go1.10.2 darwin/amd64
+ go test -c
+ go tool objdump -s bmi.PDep bmi.test
TEXT github.com/mmcloughlin/bmi.PDep(SB) /Users/michaelmcloughlin/gocode/src/github.com/mmcloughlin/bmi/pdep.s
  pdep.s:7		0x10e7860		4c8b442408		MOVQ 0x8(SP), R8
  pdep.s:8		0x10e7865		4c8b4c2410		MOVQ 0x10(SP), R9
  pdep.s:10		0x10e786a		c442b3f5		CMC
  pdep.s:10		0x10e786e		d04c8954		RORB $0x1, 0x54(CX)(CX*4)
  pdep.s:12		0x10e7872		2418			ANDL $0x18, AL
  pdep.s:13		0x10e7874		c3			RET
  :-1			0x10e7875		cc			INT $0x3
  :-1			0x10e7876		cc			INT $0x3
  :-1			0x10e7877		cc			INT $0x3
  :-1			0x10e7878		cc			INT $0x3
  :-1			0x10e7879		cc			INT $0x3
  :-1			0x10e787a		cc			INT $0x3
  :-1			0x10e787b		cc			INT $0x3
  :-1			0x10e787c		cc			INT $0x3
  :-1			0x10e787d		cc			INT $0x3
  :-1			0x10e787e		cc			INT $0x3
  :-1			0x10e787f		cc			INT $0x3
+ objdump -disassemble-all bmi.test
+ grep -A 4 bmi.PDep:
github.com/mmcloughlin/bmi.PDep:
 10e7860:	4c 8b 44 24 08 	movq	8(%rsp), %r8
 10e7865:	4c 8b 4c 24 10 	movq	16(%rsp), %r9
 10e786a:	c4 42 b3 f5 d0 	pdepq	%r8, %r9, %r10
 10e786f:	4c 89 54 24 18 	movq	%r10, 24(%rsp)

objdump.sh

#!/bin/bash -x

go version

go test -c

go tool objdump -s bmi.PDep bmi.test

objdump -disassemble-all bmi.test | grep -A 4 'bmi.PDep:'

pdep.go

package bmi

func PDep(mask, x uint64) uint64

pdep.s

// +build amd64

#include "textflag.h"

// func PDep(mask, x uint64) uint64
TEXT ·PDep(SB), NOSPLIT, $0
	MOVQ mask+0(FP), R8
	MOVQ x+8(FP), R9

	PDEPQ R8, R9, R10

	MOVQ R10, ret+16(FP)
	RET

pdep_test.go

package bmi

import (
	"testing"
)

func TestPDep(t *testing.T) {
	m := uint64(0x0001000100010001)
	x := uint64(0x5)
	e := uint64(0x0000000100000001)

	r := PDep(m, x)
	t.Logf("m=%016x x=%016x r=%016x\n", m, x, r)

	if r != e {
		t.Fail()
	}
}