| // Copyright 2012 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| package gc |
| |
| import ( |
| "cmd/compile/internal/types" |
| "cmd/internal/src" |
| "fmt" |
| "strings" |
| ) |
| |
| // The instrument pass modifies the code tree for instrumentation. |
| // |
| // For flag_race it modifies the function as follows: |
| // |
| // 1. It inserts a call to racefuncenterfp at the beginning of each function. |
| // 2. It inserts a call to racefuncexit at the end of each function. |
| // 3. It inserts a call to raceread before each memory read. |
| // 4. It inserts a call to racewrite before each memory write. |
| // |
| // For flag_msan: |
| // |
| // 1. It inserts a call to msanread before each memory read. |
| // 2. It inserts a call to msanwrite before each memory write. |
| // |
| // The rewriting is not yet complete. Certain nodes are not rewritten |
| // but should be. |
| |
| // TODO(dvyukov): do not instrument initialization as writes: |
| // a := make([]int, 10) |
| |
| // Do not instrument the following packages at all, |
| // at best instrumentation would cause infinite recursion. |
| var omit_pkgs = []string{"runtime/internal/atomic", "runtime/internal/sys", "runtime", "runtime/race", "runtime/msan"} |
| |
| // Only insert racefuncenterfp/racefuncexit into the following packages. |
| // Memory accesses in the packages are either uninteresting or will cause false positives. |
| var norace_inst_pkgs = []string{"sync", "sync/atomic"} |
| |
| func ispkgin(pkgs []string) bool { |
| if myimportpath != "" { |
| for _, p := range pkgs { |
| if myimportpath == p { |
| return true |
| } |
| } |
| } |
| |
| return false |
| } |
| |
| func instrument(fn *Node) { |
| if ispkgin(omit_pkgs) || fn.Func.Pragma&Norace != 0 { |
| return |
| } |
| |
| if !flag_race || !ispkgin(norace_inst_pkgs) { |
| instrumentlist(fn.Nbody, nil) |
| |
| // nothing interesting for race detector in fn->enter |
| instrumentlist(fn.Func.Exit, nil) |
| } |
| |
| if flag_race { |
| // nodpc is the PC of the caller as extracted by |
| // getcallerpc. We use -widthptr(FP) for x86. |
| // BUG: this will not work on arm. |
| nodpc := *nodfp |
| nodpc.Type = types.Types[TUINTPTR] |
| nodpc.Xoffset = int64(-Widthptr) |
| nd := mkcall("racefuncenter", nil, nil, &nodpc) |
| fn.Func.Enter.Prepend(nd) |
| nd = mkcall("racefuncexit", nil, nil) |
| fn.Func.Exit.Append(nd) |
| fn.Func.Dcl = append(fn.Func.Dcl, &nodpc) |
| } |
| |
| if Debug['W'] != 0 { |
| s := fmt.Sprintf("after instrument %v", fn.Func.Nname.Sym) |
| dumplist(s, fn.Nbody) |
| s = fmt.Sprintf("enter %v", fn.Func.Nname.Sym) |
| dumplist(s, fn.Func.Enter) |
| s = fmt.Sprintf("exit %v", fn.Func.Nname.Sym) |
| dumplist(s, fn.Func.Exit) |
| } |
| } |
| |
| func instrumentlist(l Nodes, init *Nodes) { |
| s := l.Slice() |
| for i := range s { |
| var instr Nodes |
| instrumentnode(&s[i], &instr, 0, 0) |
| if init == nil { |
| s[i].Ninit.AppendNodes(&instr) |
| } else { |
| init.AppendNodes(&instr) |
| } |
| } |
| } |
| |
| // walkexpr and walkstmt combined |
| // walks the tree and adds calls to the |
| // instrumentation code to top-level (statement) nodes' init |
| func instrumentnode(np **Node, init *Nodes, wr int, skip int) { |
| n := *np |
| |
| if n == nil { |
| return |
| } |
| |
| if Debug['w'] > 1 { |
| Dump("instrument-before", n) |
| } |
| setlineno(n) |
| if init == nil { |
| Fatalf("instrument: bad init list") |
| } |
| if init == &n.Ninit { |
| // If init == &n->ninit and n->ninit is non-nil, |
| // instrumentnode might append it to itself. |
| // nil it out and handle it separately before putting it back. |
| l := n.Ninit |
| |
| n.Ninit.Set(nil) |
| instrumentlist(l, nil) |
| instrumentnode(&n, &l, wr, skip) // recurse with nil n->ninit |
| appendinit(&n, l) |
| *np = n |
| return |
| } |
| |
| instrumentlist(n.Ninit, nil) |
| |
| switch n.Op { |
| default: |
| Fatalf("instrument: unknown node type %v", n.Op) |
| |
| case OAS, OAS2FUNC: |
| instrumentnode(&n.Left, init, 1, 0) |
| instrumentnode(&n.Right, init, 0, 0) |
| goto ret |
| |
| // can't matter |
| case OCFUNC, OVARKILL, OVARLIVE: |
| goto ret |
| |
| case OBLOCK: |
| ls := n.List.Slice() |
| afterCall := false |
| for i := range ls { |
| op := ls[i].Op |
| // Scan past OAS nodes copying results off stack. |
| // Those must not be instrumented, because the |
| // instrumentation calls will smash the results. |
| // The assignments are to temporaries, so they cannot |
| // be involved in races and need not be instrumented. |
| if afterCall && op == OAS && iscallret(ls[i].Right) { |
| continue |
| } |
| instrumentnode(&ls[i], &ls[i].Ninit, 0, 0) |
| afterCall = (op == OCALLFUNC || op == OCALLMETH || op == OCALLINTER) |
| } |
| goto ret |
| |
| case ODEFER: |
| instrumentnode(&n.Left, init, 0, 0) |
| goto ret |
| |
| case OPROC: |
| instrumentnode(&n.Left, init, 0, 0) |
| goto ret |
| |
| case OCALLINTER: |
| instrumentnode(&n.Left, init, 0, 0) |
| goto ret |
| |
| // Instrument dst argument of runtime.writebarrier* calls |
| // as we do not instrument runtime code. |
| // typedslicecopy is instrumented in runtime. |
| case OCALLFUNC: |
| instrumentnode(&n.Left, init, 0, 0) |
| goto ret |
| |
| case ONOT, |
| OMINUS, |
| OPLUS, |
| OREAL, |
| OIMAG, |
| OCOM: |
| instrumentnode(&n.Left, init, wr, 0) |
| goto ret |
| |
| case ODOTINTER: |
| instrumentnode(&n.Left, init, 0, 0) |
| goto ret |
| |
| case ODOT: |
| instrumentnode(&n.Left, init, 0, 1) |
| callinstr(&n, init, wr, skip) |
| goto ret |
| |
| case ODOTPTR: // dst = (*x).f with implicit *; otherwise it's ODOT+OIND |
| instrumentnode(&n.Left, init, 0, 0) |
| |
| callinstr(&n, init, wr, skip) |
| goto ret |
| |
| case OIND: // *p |
| instrumentnode(&n.Left, init, 0, 0) |
| |
| callinstr(&n, init, wr, skip) |
| goto ret |
| |
| case OSPTR, OLEN, OCAP: |
| instrumentnode(&n.Left, init, 0, 0) |
| if n.Left.Type.IsMap() { |
| n1 := nod(OCONVNOP, n.Left, nil) |
| n1.Type = types.NewPtr(types.Types[TUINT8]) |
| n1 = nod(OIND, n1, nil) |
| n1 = typecheck(n1, Erv) |
| callinstr(&n1, init, 0, skip) |
| } |
| |
| goto ret |
| |
| case OLSH, |
| ORSH, |
| OAND, |
| OANDNOT, |
| OOR, |
| OXOR, |
| OSUB, |
| OMUL, |
| OEQ, |
| ONE, |
| OLT, |
| OLE, |
| OGE, |
| OGT, |
| OADD, |
| OCOMPLEX: |
| instrumentnode(&n.Left, init, wr, 0) |
| instrumentnode(&n.Right, init, wr, 0) |
| goto ret |
| |
| case OANDAND, OOROR: |
| instrumentnode(&n.Left, init, wr, 0) |
| |
| // walk has ensured the node has moved to a location where |
| // side effects are safe. |
| // n->right may not be executed, |
| // so instrumentation goes to n->right->ninit, not init. |
| instrumentnode(&n.Right, &n.Right.Ninit, wr, 0) |
| |
| goto ret |
| |
| case ONAME: |
| callinstr(&n, init, wr, skip) |
| goto ret |
| |
| case OCONV: |
| instrumentnode(&n.Left, init, wr, 0) |
| goto ret |
| |
| case OCONVNOP: |
| instrumentnode(&n.Left, init, wr, 0) |
| goto ret |
| |
| case ODIV, OMOD: |
| instrumentnode(&n.Left, init, wr, 0) |
| instrumentnode(&n.Right, init, wr, 0) |
| goto ret |
| |
| case OINDEX: |
| if !n.Left.Type.IsArray() { |
| instrumentnode(&n.Left, init, 0, 0) |
| } else if !islvalue(n.Left) { |
| // index of unaddressable array, like Map[k][i]. |
| instrumentnode(&n.Left, init, wr, 0) |
| |
| instrumentnode(&n.Right, init, 0, 0) |
| goto ret |
| } |
| |
| instrumentnode(&n.Right, init, 0, 0) |
| if !n.Left.Type.IsString() { |
| callinstr(&n, init, wr, skip) |
| } |
| goto ret |
| |
| case OSLICE, OSLICEARR, OSLICE3, OSLICE3ARR, OSLICESTR: |
| instrumentnode(&n.Left, init, 0, 0) |
| low, high, max := n.SliceBounds() |
| instrumentnode(&low, init, 0, 0) |
| instrumentnode(&high, init, 0, 0) |
| instrumentnode(&max, init, 0, 0) |
| n.SetSliceBounds(low, high, max) |
| goto ret |
| |
| case OADDR: |
| instrumentnode(&n.Left, init, 0, 1) |
| goto ret |
| |
| // n->left is Type* which is not interesting. |
| case OEFACE: |
| instrumentnode(&n.Right, init, 0, 0) |
| |
| goto ret |
| |
| case OITAB, OIDATA: |
| instrumentnode(&n.Left, init, 0, 0) |
| goto ret |
| |
| case OSTRARRAYBYTETMP: |
| instrumentnode(&n.Left, init, 0, 0) |
| goto ret |
| |
| case OAS2DOTTYPE: |
| instrumentnode(&n.Left, init, 1, 0) |
| instrumentnode(&n.Right, init, 0, 0) |
| goto ret |
| |
| case ODOTTYPE, ODOTTYPE2: |
| instrumentnode(&n.Left, init, 0, 0) |
| goto ret |
| |
| // should not appear in AST by now |
| case OSEND, |
| ORECV, |
| OCLOSE, |
| ONEW, |
| OXCASE, |
| OXFALL, |
| OCASE, |
| OPANIC, |
| ORECOVER, |
| OCONVIFACE, |
| OCMPIFACE, |
| OMAKECHAN, |
| OMAKEMAP, |
| OMAKESLICE, |
| OCALL, |
| OCOPY, |
| OAPPEND, |
| ORUNESTR, |
| OARRAYBYTESTR, |
| OARRAYRUNESTR, |
| OSTRARRAYBYTE, |
| OSTRARRAYRUNE, |
| OINDEXMAP, |
| // lowered to call |
| OCMPSTR, |
| OADDSTR, |
| OCALLPART, |
| // lowered to PTRLIT |
| OCLOSURE, // lowered to PTRLIT |
| ORANGE, // lowered to ordinary for loop |
| OARRAYLIT, // lowered to assignments |
| OSLICELIT, |
| OMAPLIT, |
| OSTRUCTLIT, |
| OAS2, |
| OAS2RECV, |
| OAS2MAPR, |
| OASOP: |
| Fatalf("instrument: %v must be lowered by now", n.Op) |
| |
| case OGETG: |
| Fatalf("instrument: OGETG can happen only in runtime which we don't instrument") |
| |
| case OFOR, OFORUNTIL: |
| if n.Left != nil { |
| instrumentnode(&n.Left, &n.Left.Ninit, 0, 0) |
| } |
| if n.Right != nil { |
| instrumentnode(&n.Right, &n.Right.Ninit, 0, 0) |
| } |
| goto ret |
| |
| case OIF, OSWITCH: |
| if n.Left != nil { |
| instrumentnode(&n.Left, &n.Left.Ninit, 0, 0) |
| } |
| goto ret |
| |
| // just do generic traversal |
| case OCALLMETH, |
| ORETURN, |
| ORETJMP, |
| OSELECT, |
| OEMPTY, |
| OBREAK, |
| OCONTINUE, |
| OFALL, |
| OGOTO, |
| OLABEL: |
| goto ret |
| |
| // does not require instrumentation |
| case OPRINT, // don't bother instrumenting it |
| OPRINTN, // don't bother instrumenting it |
| OCHECKNIL, // always followed by a read. |
| OCLOSUREVAR, // immutable pointer to captured variable |
| ODOTMETH, // either part of CALLMETH or CALLPART (lowered to PTRLIT) |
| OINDREGSP, // at this stage, only n(SP) nodes from nodarg |
| ODCL, // declarations (without value) cannot be races |
| ODCLCONST, |
| ODCLTYPE, |
| OTYPE, |
| ONONAME, |
| OLITERAL, |
| OTYPESW: // ignored by code generation, do not instrument. |
| goto ret |
| } |
| |
| ret: |
| if n.Op != OBLOCK { // OBLOCK is handled above in a special way. |
| instrumentlist(n.List, init) |
| } |
| instrumentlist(n.Nbody, nil) |
| instrumentlist(n.Rlist, nil) |
| *np = n |
| } |
| |
| func isartificial(n *Node) bool { |
| // compiler-emitted artificial things that we do not want to instrument, |
| // can't possibly participate in a data race. |
| // can't be seen by C/C++ and therefore irrelevant for msan. |
| if n.Op == ONAME && n.Sym != nil && n.Sym.Name != "" { |
| if n.Sym.Name == "_" { |
| return true |
| } |
| |
| // autotmp's are always local |
| if n.IsAutoTmp() { |
| return true |
| } |
| |
| // statictmp's are read-only |
| if strings.HasPrefix(n.Sym.Name, "statictmp_") { |
| return true |
| } |
| |
| // go.itab is accessed only by the compiler and runtime (assume safe) |
| if n.Sym.Pkg != nil && n.Sym.Pkg.Name != "" && n.Sym.Pkg.Name == "go.itab" { |
| return true |
| } |
| } |
| |
| return false |
| } |
| |
| func callinstr(np **Node, init *Nodes, wr int, skip int) bool { |
| n := *np |
| |
| //fmt.Printf("callinstr for %v [ %v ] etype=%v class=%v\n", |
| // n, n.Op, n.Type.Etype, n.Class) |
| |
| if skip != 0 || n.Type == nil || n.Type.Etype >= TIDEAL { |
| return false |
| } |
| t := n.Type |
| if isartificial(n) { |
| return false |
| } |
| |
| b := outervalue(n) |
| |
| // it skips e.g. stores to ... parameter array |
| if isartificial(b) { |
| return false |
| } |
| class := b.Class |
| |
| // BUG: we _may_ want to instrument PAUTO sometimes |
| // e.g. if we've got a local variable/method receiver |
| // that has got a pointer inside. Whether it points to |
| // the heap or not is impossible to know at compile time |
| if class == PAUTOHEAP || class == PEXTERN || b.Op == OINDEX || b.Op == ODOTPTR || b.Op == OIND { |
| hascalls := 0 |
| foreach(n, hascallspred, &hascalls) |
| if hascalls != 0 { |
| n = detachexpr(n, init) |
| *np = n |
| } |
| |
| n = treecopy(n, src.NoXPos) |
| makeaddable(n) |
| var f *Node |
| if flag_msan { |
| name := "msanread" |
| if wr != 0 { |
| name = "msanwrite" |
| } |
| // dowidth may not have been called for PEXTERN. |
| dowidth(t) |
| w := t.Width |
| if w == BADWIDTH { |
| Fatalf("instrument: %v badwidth", t) |
| } |
| f = mkcall(name, nil, init, uintptraddr(n), nodintconst(w)) |
| } else if flag_race && (t.IsStruct() || t.IsArray()) { |
| name := "racereadrange" |
| if wr != 0 { |
| name = "racewriterange" |
| } |
| // dowidth may not have been called for PEXTERN. |
| dowidth(t) |
| w := t.Width |
| if w == BADWIDTH { |
| Fatalf("instrument: %v badwidth", t) |
| } |
| f = mkcall(name, nil, init, uintptraddr(n), nodintconst(w)) |
| } else if flag_race { |
| name := "raceread" |
| if wr != 0 { |
| name = "racewrite" |
| } |
| f = mkcall(name, nil, init, uintptraddr(n)) |
| } |
| |
| init.Append(f) |
| return true |
| } |
| |
| return false |
| } |
| |
| // makeaddable returns a node whose memory location is the |
| // same as n, but which is addressable in the Go language |
| // sense. |
| // This is different from functions like cheapexpr that may make |
| // a copy of their argument. |
| func makeaddable(n *Node) { |
| // The arguments to uintptraddr technically have an address but |
| // may not be addressable in the Go sense: for example, in the case |
| // of T(v).Field where T is a struct type and v is |
| // an addressable value. |
| switch n.Op { |
| case OINDEX: |
| if n.Left.Type.IsArray() { |
| makeaddable(n.Left) |
| } |
| |
| // Turn T(v).Field into v.Field |
| case ODOT, OXDOT: |
| if n.Left.Op == OCONVNOP { |
| n.Left = n.Left.Left |
| } |
| makeaddable(n.Left) |
| |
| // nothing to do |
| case ODOTPTR: |
| fallthrough |
| default: |
| break |
| } |
| } |
| |
| func uintptraddr(n *Node) *Node { |
| r := nod(OADDR, n, nil) |
| r.SetBounded(true) |
| r = conv(r, types.Types[TUNSAFEPTR]) |
| r = conv(r, types.Types[TUINTPTR]) |
| return r |
| } |
| |
| func detachexpr(n *Node, init *Nodes) *Node { |
| addr := nod(OADDR, n, nil) |
| l := temp(types.NewPtr(n.Type)) |
| as := nod(OAS, l, addr) |
| as = typecheck(as, Etop) |
| as = walkexpr(as, init) |
| init.Append(as) |
| ind := nod(OIND, l, nil) |
| ind = typecheck(ind, Erv) |
| ind = walkexpr(ind, init) |
| return ind |
| } |
| |
| func foreachnode(n *Node, f func(*Node, interface{}), c interface{}) { |
| if n != nil { |
| f(n, c) |
| } |
| } |
| |
| func foreachlist(l Nodes, f func(*Node, interface{}), c interface{}) { |
| for _, n := range l.Slice() { |
| foreachnode(n, f, c) |
| } |
| } |
| |
| func foreach(n *Node, f func(*Node, interface{}), c interface{}) { |
| foreachlist(n.Ninit, f, c) |
| foreachnode(n.Left, f, c) |
| foreachnode(n.Right, f, c) |
| foreachlist(n.List, f, c) |
| foreachlist(n.Nbody, f, c) |
| foreachlist(n.Rlist, f, c) |
| } |
| |
| func hascallspred(n *Node, c interface{}) { |
| switch n.Op { |
| case OCALL, OCALLFUNC, OCALLMETH, OCALLINTER: |
| (*c.(*int))++ |
| } |
| } |
| |
| // appendinit is like addinit in subr.go |
| // but appends rather than prepends. |
| func appendinit(np **Node, init Nodes) { |
| if init.Len() == 0 { |
| return |
| } |
| |
| n := *np |
| switch n.Op { |
| // There may be multiple refs to this node; |
| // introduce OCONVNOP to hold init list. |
| case ONAME, OLITERAL: |
| n = nod(OCONVNOP, n, nil) |
| |
| n.Type = n.Left.Type |
| n.Typecheck = 1 |
| *np = n |
| } |
| |
| n.Ninit.AppendNodes(&init) |
| n.SetHasCall(true) |
| } |
