go: cmd/pprof: disasm not working on darwin

I stub my toe on this UX about every other time I use pprof.

Getting the same problem on Windows:

PS C:\Users\a3367\work\misc\seg> go run .\cmd\vizccl\main.go
2022/03/29 13:28:17.416938 C:/Users/a3367/work/misc/seg/cmd/vizccl/main.go:45: png write start output\vizqqq.png
2022/03/29 13:28:48.685875 C:/Users/a3367/work/misc/seg/cmd/vizccl/main.go:55: png write end output\vizqqq.png
PS C:\Users\a3367\work\misc\seg>
PS C:\Users\a3367\work\misc\seg\output> go tool pprof .\png_encode.pprof
Type: cpu
Time: Mar 29, 2022 at 1:28pm (CST)
Duration: 31.43s, Total samples = 17.53s (55.77%)
Entering interactive mode (type "help" for commands, "o" for options)
(pprof) top
Showing nodes accounting for 16.92s, 96.52% of 17.53s total
Dropped 91 nodes (cum <= 0.09s)
Showing top 10 nodes out of 29
      flat  flat%   sum%        cum   cum%
     7.96s 45.41% 45.41%     13.07s 74.56%  image/png.filter
        2s 11.41% 56.82%      2.01s 11.47%  image/png.abs
     1.74s  9.93% 66.74%      1.74s  9.93%  runtime.memmove
     1.56s  8.90% 75.64%      1.56s  8.90%  image/png.abs8
     1.44s  8.21% 83.86%      3.46s 19.74%  image/png.paeth
     0.90s  5.13% 88.99%      0.90s  5.13%  hash/adler32.update
     0.80s  4.56% 93.55%      0.81s  4.62%  compress/flate.(*deflateFast).matchLen
     0.29s  1.65% 95.21%      0.31s  1.77%  compress/flate.(*huffmanEncoder).bitCounts
     0.12s  0.68% 95.89%      0.12s  0.68%  runtime.asyncPreempt
     0.11s  0.63% 96.52%      1.04s  5.93%  compress/flate.(*deflateFast).encode
(pprof) disasm png.abs8
Total: 17.53s
(pprof)

$ go version
go version go1.17.6 windows/amd64

$ go env
set GO111MODULE=
set GOARCH=amd64
set GOBIN=
set GOCACHE=C:\Users\a3367\AppData\Local\go-build
set GOENV=C:\Users\a3367\AppData\Roaming\go\env
set GOEXE=.exe
set GOEXPERIMENT=
set GOFLAGS=
set GOHOSTARCH=amd64
set GOHOSTOS=windows
set GOINSECURE=
set GOMODCACHE=C:\Users\a3367\go\pkg\mod
set GONOPROXY=
set GONOSUMDB=
set GOOS=windows
set GOPATH=C:\Users\a3367\go
set GOPRIVATE=
set GOPROXY=https://proxy.golang.org,direct
set GOROOT=C:\Program Files\Go
set GOSUMDB=sum.golang.org
set GOTMPDIR=
set GOTOOLDIR=C:\Program Files\Go\pkg\tool\windows_amd64
set GOVCS=
set GOVERSION=go1.17.6
set GCCGO=gccgo
set AR=ar
set CC=gcc
set CXX=g++
set CGO_ENABLED=1
set GOMOD=NUL
set CGO_CFLAGS=-g -O2
set CGO_CPPFLAGS=
set CGO_CXXFLAGS=-g -O2
set CGO_FFLAGS=-g -O2
set CGO_LDFLAGS=-g -O2
set PKG_CONFIG=pkg-config
set GOGCCFLAGS=-m64 -mthreads -fmessage-length=0 -fdebug-prefix-map=C:\Users\a3367\AppData\Local\Temp\go-build2334633044=/tmp/go-build -gno-record-gcc-switches
gdb --version: GNU gdb (GDB) 8.1

go test -cpuprofile=x.prof strings will leave a strings.test binary in the working directory. If pprof is invoked as go tool pprof x.prof, disasm fails because it’s looking for the binary in /tmp/, and it’s not there:

(pprof) disasm cmpbody
open /tmp/go-build477592094/b001/strings.test: no such file or directory
no matches found for regexp: cmpbody

but if the binary (which is in wd) is explicitly passed as go tool pprof strings.test x.prof, then disasm works correctly.

FWIW, I see the same behaviour with go1.17.5 (above tests are from tip).

(This is on Linux).

Take a look at https://go-review.googlesource.com/c/go/+/503919 when you have a moment, it includes your changes too.

FYI, I have the arm version of vm_region_info working. What are your plans for merging the linker changes and how should I construct the PRs for my changes - i.e. would you like to see one PR with the mach_vm_region assembly code and a second one with the pprof mapping changes, or would you prefer one? I would assume one, but lmk.

Yep - it does indeed work for arm64! Thanks! I’ll try the intel version when I get back home in a week or so and have access to an intel mbp.