cmd/compile: sanity check in makePreinlineDclMap can fail #38698
Description
package p
func ff( /*line :10*/ x string) bool {
{
var _ /*line :10*/, x int
_ = x
}
return x == ""
}
func h(a string) bool {
return ff(a)
}$ go tool compile -S bug.go
:17: internal compiler error: child dcl collision on symbol x within "".ff
goroutine 1 [running]:
runtime/debug.Stack(0x19892e0, 0xc0000ac008, 0x0)
/Users/josh/go/tip/src/runtime/debug/stack.go:24 +0x9d
cmd/compile/internal/gc.Fatalf(0x1829099, 0x2b, 0xc0003c2f68, 0x2, 0x2)
/Users/josh/go/tip/src/cmd/compile/internal/gc/subr.go:193 +0x1aa
cmd/compile/internal/gc.makePreinlineDclMap(0xc0003b4580, 0xc0003c31b8)
/Users/josh/go/tip/src/cmd/compile/internal/gc/dwinl.go:225 +0x337
cmd/compile/internal/gc.assembleInlines(0xc0003b4580, 0xc0003dc4c0, 0x3, 0x4, 0x4, 0xc0000b2cc0, 0x3)
/Users/josh/go/tip/src/cmd/compile/internal/gc/dwinl.go:106 +0x52d
cmd/compile/internal/gc.debuginfo(0xc0003b4580, 0xc0003b4680, 0x18056c0, 0xc00039e3c0, 0x20, 0x30, 0x30, 0xc0003d31d0, 0xc00008ed60, 0x10)
/Users/josh/go/tip/src/cmd/compile/internal/gc/pgen.go:434 +0x9b3
cmd/internal/obj.(*Link).DwarfAbstractFunc(0xc0001701a0, 0x18056c0, 0xc00039e3c0, 0xc0003b4580, 0x0, 0x0)
/Users/josh/go/tip/src/cmd/internal/obj/objfile.go:675 +0xb6
cmd/compile/internal/gc.genAbstractFunc(0xc0003b4580)
/Users/josh/go/tip/src/cmd/compile/internal/gc/dwinl.go:195 +0xb8
cmd/internal/obj.(*DwarfFixupTable).Finalize(0xc0000b1140, 0x0, 0x0, 0x0)
/Users/josh/go/tip/src/cmd/internal/obj/objfile.go:926 +0x224
cmd/compile/internal/gc.Main(0x18357e0)
/Users/josh/go/tip/src/cmd/compile/internal/gc/main.go:769 +0x3b67
main.main()
/Users/josh/go/tip/src/cmd/compile/main.go:52 +0xac
This code is obviously contrived/ridiculous, but the point remains--in the presence of line directives, we cannot safely assume that the contents of any given source positions are unique.
cc @thanm