ianlancetaylor
commented
10 years ago Closed DanielMorsing closed 9 years ago
ianlancetaylor
commented
10 years ago 
gopherbot
commented
10 years ago CL https://golang.org/cl/163350043 mentions this issue.
adonovan
commented
10 years ago
The following program causes the pointer analysis to fail: package main func main() { ch := make(chan *int) <-ch for range ch { } } Querying for peers at <-ch causes a panic. Panic and pointer analysis log: ==== Starting analysis ==== Generating constraints create n0 invalid type for (zero) create n1 interface{} for panic create n2 func() for root.targets root call to main.init: create n3 func() for main.init ---- makeFunctionObject main.init create n4 func() for func.cgnode ---- globalobj[main.init] = n4 addr n3 <- {&n4} val[init] = n3 (*ssa.Function) copy n2 <- n3 root call to main.main: create n5 func() for main.main ---- makeFunctionObject main.main create n6 func() for func.cgnode ---- globalobj[main.main] = n6 addr n5 <- {&n6} val[main] = n5 (*ssa.Function) copy n2 <- n5 ==== Generating constraints for cg4:main.init, shared contour # Name: main.init # Package: main # Synthetic: package initializer func init(): 0: entry P:0 S:2 t0 = *init$guard bool if t0 goto 2 else 1 1: init.start P:1 S:1 *init$guard = true:bool jump 2 2: ao: exit 2 init.done P:2 S:0 return ; Creating nodes for local values create n7 bool for t0 val[t0] = n7 (*ssa.UnOp) ; t0 = *init$guard create n8 bool for global globalobj[main.init$guard] = n8 copy n7 <- n8 ; if t0 goto 2 else 1 ; *init$guard = true:bool create n9 bool for true:bool globalobj[true:bool] = n0 val[true:bool] = n9 (*ssa.Const) copy n8 <- n9 ; jump 2 ; return ==== Generating constraints for cg6:main.main, shared contour # Name: main.main # Package: main # Location: /home/daniel/src/test/te.go:3:6 func main(): 0: entry P:0 S:1 t0 = make chan *int 0:int chan *int ; *ast.CallExpr @ 4:8 is t0 ; var ch chan *int @ 4:2 is t0 ; var ch chan *int @ 5:4 is t0 t1 = <-t0 *int ; *ast.UnaryExpr @ 5:2 is t1 ; var ch chan *int @ 6:12 is t0 jump 1 1: rangechan.loop P:2 S:2 t2 = <-t0,ok (k *int, ok bool) t3 = extract t2 #1 bool if t3 goto 1 else 2 2: rangechan.done P:1 S:0 return ; Creating nodes for local values create n10 chan *int for t0 val[t0] = n10 (*ssa.MakeChan) create n11 chan *int for query copy n11 <- n10 create n12 *int for t1 val[t1] = n12 (*ssa.UnOp) create n13 *int for t2#0 create n14 bool for t2#1 val[t2] = n13 (*ssa.UnOp) create n15 bool for t3 val[t3] = n15 (*ssa.Extract) ; t0 = make chan *int 0:int create n16 *int for makechan localobj[t0] = n16 addr n10 <- {&n16} ; ; *ast.CallExpr @ 4:8 is t0 ; ; var ch chan *int @ 4:2 is t0 ; ; var ch chan *int @ 5:4 is t0 ; t1 = <-t0 copy n12 <- n16 ; ; *ast.UnaryExpr @ 5:2 is t1 ; ; var ch chan *int @ 6:12 is t0 ; jump 1 ; t2 = <-t0,ok copy n13 <- n16 copy n14 <- n17 ; t3 = extract t2 #1 copy n15 <- n14 ; if t3 goto 1 else 2 ; return # constraints: 12 9 (75%) *pointer.copyConstraint 3 (25%) *pointer.addrConstraint # nodes: 17 # ptsets: 17 ==== Renumbering Renumbering nodes to improve density: (5 object nodes of 17 total) n0 -> n0 n1 -> n5 n2 -> n6 n3 -> n7 n4 -> n1 n5 -> n8 n6 -> n2 n7 -> n9 n8 -> n3 n9 -> n10 n10 -> n11 n11 -> n12 n12 -> n13 n13 -> n14 n14 -> n15 n15 -> n16 n16 -> n4 Internal panic in pointer analysis: /home/daniel/src/goprj/src/code.google.com/p/go.tools/go/pointer/analysis.go:222 (0x6ca1bc) func.001: debug.PrintStack() /home/daniel/src/godev/src/runtime/asm_amd64.s:401 (0x43dff5) call16: CALLFN(·call16, 16) /home/daniel/src/godev/src/runtime/panic.go:387 (0x416768) gopanic: reflectcall(unsafe.Pointer(d.fn), deferArgs(d), uint32(d.siz), uint32(d.siz)) /home/daniel/src/godev/src/runtime/panic.go:12 (0x4158fe) panicindex: panic(indexError) /home/daniel/src/goprj/src/code.google.com/p/go.tools/go/pointer/constraint.go:56 (0x698fd5) (*copyConstraint).renumber: c.src = mapping[c.src] /home/daniel/src/goprj/src/code.google.com/p/go.tools/go/pointer/opt.go:113 (0x6b1aba) (*analysis).renumber: c.renumber(renumbering) /home/daniel/src/goprj/src/code.google.com/p/go.tools/go/pointer/analysis.go:291 (0x694bb5) Analyze: a.renumber() /home/daniel/src/goprj/src/code.google.com/p/go.tools/oracle/oracle.go:477 (0x4adfb4) ptrAnalysis: result, err := pointer.Analyze(&o.ptaConfig) /home/daniel/src/goprj/src/code.google.com/p/go.tools/oracle/peers.go:73 (0x4af2ab) peers: ptares := ptrAnalysis(o) /home/daniel/src/goprj/src/code.google.com/p/go.tools/oracle/oracle.go:419 (0x4ad5fb) (*Oracle).query: res.q, err = minfo.impl(o, qpos) /home/daniel/src/goprj/src/code.google.com/p/go.tools/oracle/oracle.go:406 (0x4ad4b3) (*Oracle).Query: return o.query(minfo, qpos) /home/daniel/src/goprj/src/github.com/DanielMorsing/ao/main.go:84 (0x401a0d) main: res, err := oracl.Query(mode, qp) /home/daniel/src/godev/src/runtime/proc.go:63 (0x4182b3) main: main_main() /home/daniel/src/godev/src/runtime/proc.c:1651 (0x435d00) goexit: runtime·goexit(void) panic: internal error in pointer analysis: runtime error: index out of range (please report this bug) goroutine 1 [running]: code.google.com/p/go.tools/oracle.ptrAnalysis(0xc20805cd20, 0x0) /home/daniel/src/goprj/src/code.google.com/p/go.tools/oracle/oracle.go:479 +0x79 code.google.com/p/go.tools/oracle.peers(0xc20805cd20, 0xc20802a940, 0x0, 0x0, 0x0, 0x0) /home/daniel/src/goprj/src/code.google.com/p/go.tools/oracle/peers.go:73 +0x90b code.google.com/p/go.tools/oracle.(*Oracle).query(0xc20805cd20, 0xa6eca0, 0xc20802a940, 0x0, 0x0, 0x0) /home/daniel/src/goprj/src/code.google.com/p/go.tools/oracle/oracle.go:419 +0x10b code.google.com/p/go.tools/oracle.(*Oracle).Query(0xc20805cd20, 0xc20800afe0, 0x5, 0xc20802a940, 0xc20802a940, 0x0, 0x0) /home/daniel/src/goprj/src/code.google.com/p/go.tools/oracle/oracle.go:406 +0x193 main.main() /home/daniel/src/goprj/src/github.com/DanielMorsing/ao/main.go:84 +0xd5d Looks like n17 is used without it being created, causing a panic during renumbering.