runtime/pprof: incorrect locations for inlined generic functions

[korniltsev]

Go version

go version devel go1.22-de5b418bea Sat Dec 2 03:15:03 2023 +0000 linux/amd64

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

GO111MODULE=''
GOARCH='amd64'
GOBIN=''
GOCACHE='/home/korniltsev/.cache/go-build'
GOENV='/home/korniltsev/.config/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFLAGS=''
GOHOSTARCH='amd64'
GOHOSTOS='linux'
GOINSECURE=''
GOMODCACHE='/home/korniltsev/go/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='linux'
GOPATH='/home/korniltsev/go'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/home/korniltsev/github/go'
GOSUMDB='sum.golang.org'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/home/korniltsev/github/go/pkg/tool/linux_amd64'
GOVCS=''
GOVERSION='devel go1.22-de5b418bea Sat Dec 2 03:15:03 2023 +0000'
GCCGO='gccgo'
GOAMD64='v1'
AR='ar'
CC='gcc'
CXX='g++'
CGO_ENABLED='1'
GOMOD='/home/korniltsev/github/go/src/go.mod'
GOWORK=''
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
PKG_CONFIG='pkg-config'
GOGCCFLAGS='-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build3732277415=/tmp/go-build -gno-record-gcc-switches'

What did you do?

I produced a pprof profile with the following stacktrace

foo
generic[a,b]
generic[b,a]

And foo and generic[a,b] functions are inlined by the go compiler

Reproducer

More info: #64528 (comment)

What did you expect to see?

I expected to see a pprof Location with 3 Line for this case.

What did you see instead?

Isee a pprof Location with 2 Line for this case. Only

foo
generic[a,b]

and then separate location for

generic[b,a]

I suspect this is because of this line , which checks for function names without generic shapes (generic[...])

go/src/runtime/pprof/proto.go

Line 564 in de5b418

if last.Function == newFrame.Function { // maybe recursion.

[prattmic]

This is #64528 (comment), split into another bug. I think this also qualifies for the backport in #64609.

cc @golang/runtime @cherrymui

[gopherbot]

Change https://go.dev/cl/549135 mentions this issue: runtime/pprof: fix inlined generics locations