Closed
Description
$ go version
go version devel +cad6d1fef5 Mon Jan 21 23:31:09 2019 +0000 linux/amd64
$ cat test/test.go
package test
import "log"
func a() {
log.Println("%2F")
}
$ go build test
$ sed -i -e 's/func a/func _/' test/test.go
$ go build test
# test
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x60 pc=0xc4e259]
goroutine 50 [running]:
cmd/compile/internal/gc.emitStackObjects(0xc000538000, 0xc0005ea0e0)
~/goroot/src/cmd/compile/internal/gc/ssa.go:5057 +0x1c9
cmd/compile/internal/gc.genssa(0xc00053c000, 0xc0005ea0e0)
~/goroot/src/cmd/compile/internal/gc/ssa.go:5092 +0xe1
cmd/compile/internal/gc.compileSSA(0xc0000cc420, 0x1)
~/goroot/src/cmd/compile/internal/gc/pgen.go:301 +0x378
cmd/compile/internal/gc.compileFunctions.func2(0xc0004fcf60, 0xc0004fe1d0, 0x1)
~/goroot/src/cmd/compile/internal/gc/pgen.go:356 +0x49
created by cmd/compile/internal/gc.compileFunctions
~/goroot/src/cmd/compile/internal/gc/pgen.go:354 +0x129
Metadata
Metadata
Assignees
Labels
Type
Projects
Relationships
Development
No branches or pull requests
Activity
bcmills commentedon Jan 22, 2019
CC @randall77 @josharian @martisch
gopherbot commentedon Jan 22, 2019
Change https://golang.org/cl/158845 mentions this issue:
cmd/compile: don't bother compiling functions named "_"
randall77 commentedon Jan 22, 2019
This was introduced as part of adding stack objects. Fix out for review.
Do we care about functions named "_"? Is there any legitimate use for them? If so, we should fix this in 1.12. If not, we can leave for 1.13.
bcmills commentedon Jan 22, 2019
I could imagine someone using them to contain static assertions: that is, a function named
_
that fails to compile if certain conditions (such as equality of sizes) are not met.I don't know whether anyone does that in practice.
alandonovan commentedon Jan 22, 2019
Exactly. They must be type-checked, but there's no need to generate code for them.
gopherbot commentedon Jan 22, 2019
Change https://golang.org/cl/158820 mentions this issue:
cmd/compile: don't bother compiling functions named "_"
randall77 commentedon Jan 22, 2019
The latter CL is for 1.12. The former CL has more clean up in it and will go in for 1.13.
cmd/compile: don't bother compiling functions named "_"