cmd/internal/obj: symbol redeclared panics during InitTextSym

[y1yang0]

Go version

go1.24

Output of go env in your module/workspace:

hidden

What did you do?

When compiling the automatically generated code(alibaba/opentelemetry-go-auto-instrumentation#52), a panic occurred:

/test.go:5:47: internal compiler error: panic: runtime error: invalid memory address or nil pointer dereference

Please file a bug report including a short program that triggers the error.
https://go.dev/issue/new

reproduce:

package otel_rules
import _ "unsafe"
import otel_debug "runtime/debug"
//go:linkname OtelPrintStack0 otel_debug.OtelPrintStack
func OtelPrintStack0() { otel_debug.PrintStack() }
//go:linkname OtelPrintStack1 otel_debug.OtelPrintStack
func OtelPrintStack1() { otel_debug.PrintStack() } 

further reduced:

package main
import _ "unsafe"

//go:linkname a main.c
func a() {}

func c() {}

stacktrace:

/go/mytest/bug.go:6:6: internal compiler error: panic: runtime error: invalid memory address or nil pointer dereference

goroutine 1 [running]:
runtime/debug.Stack()
        /go/src/runtime/debug/stack.go:26 +0x5e
cmd/compile/internal/base.FatalfAt({0x1936d8?, 0xc0?}, {0xe3824f, 0x9}, {0xc000193708, 0x1, 0x1})
        /go/src/cmd/compile/internal/base/print.go:230 +0x1ea
cmd/compile/internal/base.Fatalf(...)
        /go/src/cmd/compile/internal/base/print.go:195
cmd/compile/internal/gc.handlePanic()
        /go/src/cmd/compile/internal/gc/main.go:54 +0x8a
panic({0xdb0de0?, 0x14edc00?})
        /go/src/runtime/panic.go:785 +0x132
cmd/internal/obj.(*Link).InitTextSym(...)
        /go/src/cmd/internal/obj/plist.go:186
cmd/compile/internal/ir.setupTextLSym(0xfb1578?, 0xc0004fad01?)
        /go/src/cmd/compile/internal/ir/abi.go:77 +0x244
cmd/compile/internal/ir.InitLSym(0xc0004f8f00, 0x1)
        /go/src/cmd/compile/internal/ir/abi.go:32 +0xea
cmd/compile/internal/gc.prepareFunc(0xc0004f8f00)
        /go/src/cmd/compile/internal/gc/compile.go:95 +0x25
cmd/compile/internal/gc.enqueueFunc(0xc0004f8f00)
        /go/src/cmd/compile/internal/gc/compile.go:76 +0x268
cmd/compile/internal/gc.Main(0xe73238)
        /go/src/cmd/compile/internal/gc/main.go:300 +0x123b
main.main()
        /go/src/cmd/compile/main.go:57 +0xf9

In reduced program, both a and c have identical LSym, i.e. main.c.

When a has a body, setupTextLSym is called for the first time, initializing LSym.Extra at

go/src/cmd/internal/obj/plist.go

Line 189 in 7fcd4a7

s.NewFuncInfo()

Then, when processing c, setupTextLSym is called again. s.Func().Text was not initialized in the previous step by s.NewFuncInfo(), leading to the below panic

go/src/cmd/internal/obj/plist.go

Line 186 in 7fcd4a7

ctxt.Diag("%s: symbol %s redeclared\n\t%s: other declaration of symbol %s", ctxt.PosTable.Pos(start), s.Name, ctxt.PosTable.Pos(s.Func().Text.Pos), s.Name)

What did you see happen?

compiler panic

What did you expect to see?

not panic

[gabyhelp]

Related Issues and Documentation

• cmd/compile: internal compiler error: panic: runtime error: invalid memory address or nil pointer dereference #51335 (closed)
• cmd/cgo: panic in enum #3368 (closed)
• text/template: Panic when an undefined variable was accessed #54149 (closed)
• cmd/compile: go:linkname causes "internal compiler error: panic: runtime error: invalid memory address or nil pointer dereference" #59621
• cmd/go/internal/work: panic for a repeated //go:debug directive for the same setting #62346 (closed)
• cmd/go2go: panic if using a method on undefined type #39672 (closed)
• cmd/cgo: go 1.3 panics on recursive use of typedef #8368 (closed)
• cmd/compile: panic while printing error when cross-compiling #20789 (closed)
• cmd/compile: internal compiler error: panic: runtime error: invalid memory address or nil pointer dereference #54302 (closed)

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[gopherbot]

Change https://go.dev/cl/606903 mentions this issue: cmd/internal/obj: symbol redeclared panics during InitTextSym

[ianlancetaylor]

Stack trace:

# command-line-arguments
foo.go:5:47: internal compiler error: panic: runtime error: invalid memory address or nil pointer dereference

goroutine 1 [running]:
runtime/debug.Stack()
	../../go/src/runtime/debug/stack.go:26 +0x5e
cmd/compile/internal/base.FatalfAt({0xe96d8?, 0xc0?}, {0xe36239, 0x9}, {0xc0000e9708, 0x1, 0x1})
	../../go/src/cmd/compile/internal/base/print.go:230 +0x1ea
cmd/compile/internal/base.Fatalf(...)
	../../go/src/cmd/compile/internal/base/print.go:195
cmd/compile/internal/gc.handlePanic()
	../../go/src/cmd/compile/internal/gc/main.go:54 +0x8a
panic({0xdaee20?, 0x14e8b40?})
	../../go/src/runtime/panic.go:785 +0x132
cmd/internal/obj.(*Link).InitTextSym(...)
	../../go/src/cmd/internal/obj/plist.go:186
cmd/compile/internal/ir.setupTextLSym(0xfaf078?, 0xc0003f7a01?)
	../../go/src/cmd/compile/internal/ir/abi.go:77 +0x244
cmd/compile/internal/ir.InitLSym(0xc0003c7400, 0x1)
	../../go/src/cmd/compile/internal/ir/abi.go:32 +0xea
cmd/compile/internal/gc.prepareFunc(0xc0003c7400)
	../../go/src/cmd/compile/internal/gc/compile.go:95 +0x25
cmd/compile/internal/gc.enqueueFunc(0xc0003c7400)
	../../go/src/cmd/compile/internal/gc/compile.go:76 +0x268
cmd/compile/internal/gc.Main(0xe711d8)
	../../go/src/cmd/compile/internal/gc/main.go:300 +0x123b
main.main()
	../../go/src/cmd/compile/main.go:57 +0xf9