go.tools/go/ssa: improve printing of anonymous functions.

Examples:
- "foo$1" becomes "pkg.foo$1"
- "init$1" (meaning the first declared "init" function) becomes "init#1",
   to distinguish it from "init$1" (meaning the first anonymous function
   within the synthetic "init" function that initializes package-level vars).

It is now an invariant that all source-level (non-synthetic)
functions have distinct names, and that all names include the
enclosing package.  Added test for this.

+ updated various clients.

LGTM=gri
R=gri
CC=golang-codereviews
https://golang.org/cl/122750043

go/loader/source_test.go

@@ -60,26 +60,26 @@ func TestEnclosingFunction(t *testing.T) {
 		// Function literal:
 		{`package main
 		  func f() { println(func() { print(300) }) }`,
-			"300", "f$1"},
+			"300", "main.f$1"},
 		// Doubly nested
 		{`package main
 		  func f() { println(func() { print(func() { print(350) })})}`,
-			"350", "f$1$1"},
+			"350", "main.f$1$1"},
 		// Implicit init for package-level var initializer.
 		{"package main; var a = 400", "400", "main.init"},
 		// No code for constants:
 		{"package main; const a = 500", "500", "(none)"},
 		// Explicit init()
-		{"package main; func init() { println(600) }", "600", "main.init$1"},
+		{"package main; func init() { println(600) }", "600", "main.init#1"},
 		// Multiple explicit init functions:
 		{`package main
 		  func init() { println("foo") }
 		  func init() { println(800) }`,
-			"800", "main.init$2"},
+			"800", "main.init#2"},
 		// init() containing FuncLit.
 		{`package main
 		  func init() { println(func(){print(900)}) }`,
-			"900", "init$1$1"},
+			"900", "main.init#1$1"},
 	}
 	for _, test := range tests {
 		conf := loader.Config{Fset: token.NewFileSet()}

go/pointer/testdata/channels.go

@@ -19,7 +19,7 @@ func chan1() {
 	print(<-chA) // @pointsto main.incr
 
 	print(chB)   // @pointsto makechan@c1makeB:13
-	print(<-chB) // @pointsto main.decr | chan1$1
+	print(<-chB) // @pointsto main.decr | main.chan1$1
 }
 
 func chan2() {
@@ -40,10 +40,10 @@ func chan2() {
 	print(<-chA) // @pointsto main.incr
 
 	print(chB)   // @pointsto makechan@c2makeB:13
-	print(<-chB) // @pointsto main.decr | chan2$1
+	print(<-chB) // @pointsto main.decr | main.chan2$1
 
 	print(chAB)   // @pointsto makechan@c2makeA:13 | makechan@c2makeB:13
-	print(<-chAB) // @pointsto main.incr | main.decr | chan2$1
+	print(<-chAB) // @pointsto main.incr | main.decr | main.chan2$1
 
 	(<-chA)(3)
 }
@@ -59,7 +59,7 @@ func chan3() {
 	print(chA)   // @pointsto makechan@c3makeA:13
 	print(<-chA) // @pointsto main.incr
 	print(chB)   // @pointsto makechan@c3makeB:13
-	print(<-chB) // @pointsto main.decr | chan3$1
+	print(<-chB) // @pointsto main.decr | main.chan3$1
 
 	(<-chA)(3)
 }

go/pointer/testdata/func.go

@@ -28,9 +28,9 @@ func func1() {
 	print(&a)    // @pointsto main.a
 }
 
-// @calls main.func1 -> func1$2
-// @calls main.func1 -> func1$1
-// @calls func1$2 ->  func1$1
+// @calls main.func1 -> main.func1$2
+// @calls main.func1 -> main.func1$1
+// @calls main.func1$2 ->  main.func1$1
 
 func func2() {
 	var x, y *int
@@ -124,7 +124,7 @@ func func6() {
 	print(f()) // @pointsto main.a
 }
 
-// @calls main.func6 -> func6$1
+// @calls main.func6 -> main.func6$1
 
 type I interface {
 	f()

go/ssa/builder.go

@@ -2110,7 +2110,7 @@ func (b *builder) buildFuncDecl(pkg *Package, decl *ast.FuncDecl) {
 	if decl.Recv == nil && id.Name == "init" {
 		pkg.ninit++
 		fn = &Function{
-			name:      fmt.Sprintf("init$%d", pkg.ninit),
+			name:      fmt.Sprintf("init#%d", pkg.ninit),
 			Signature: new(types.Signature),
 			pos:       decl.Name.NamePos,
 			Pkg:       pkg,

go/ssa/func.go

@@ -452,22 +452,33 @@ func (f *Function) emit(instr Instruction) Value {
 // The specific formatting rules are not guaranteed and may change.
 //
 // Examples:
-//      "math.IsNaN"                // a package-level function
-//      "IsNaN"                     // intra-package reference to same
-//      "(*bytes.Buffer).Bytes"     // a declared method or a wrapper
-//      "(*Buffer).Bytes"           // intra-package reference to same
-//      "(*Buffer).Bytes$thunk"     // thunk (func wrapping method; receiver is param 0)
-//      "(*Buffer).Bytes$bound"     // bound (func wrapping method; receiver supplied by closure)
-//      "main$1"                    // an anonymous function
-//      "init$1"                    // a declared init function
-//      "init"                      // the synthesized package initializer
+//      "math.IsNaN"                  // a package-level function
+//      "(*bytes.Buffer).Bytes"       // a declared method or a wrapper
+//      "(*bytes.Buffer).Bytes$thunk" // thunk (func wrapping method; receiver is param 0)
+//      "(*bytes.Buffer).Bytes$bound" // bound (func wrapping method; receiver supplied by closure)
+//      "main.main$1"                 // an anonymous function in main
+//      "main.init#1"                 // a declared init function
+//      "main.init"                   // the synthesized package initializer
 //
-// If from==f.Pkg, suppress package qualification.
+// When these functions are referred to from within the same package
+// (i.e. from == f.Pkg.Object), they are rendered without the package path.
+// For example: "IsNaN", "(*Buffer).Bytes", etc.
+//
+// Invariant: all non-synthetic functions have distinct package-qualified names.
 //
 func (f *Function) RelString(from *types.Package) string {
 	// Anonymous?
 	if f.parent != nil {
-		return f.name
+		// An anonymous function's Name() looks like "parentName$1",
+		// but its String() should include the type/package/etc.
+		parent := f.parent.RelString(from)
+		for i, anon := range f.parent.AnonFuncs {
+			if anon == f {
+				return fmt.Sprintf("%s$%d", parent, 1+i)
+			}
+		}
+
+		return f.name // should never happen
 	}
 
 	// Method (declared or wrapper)?

go/ssa/stdlib_test.go

@@ -93,8 +93,25 @@ func TestStdlib(t *testing.T) {
 		t.Errorf("Loaded only %d packages, want at least %d", numPkgs, want)
 	}
 
-	// Dump some statistics.
 	allFuncs := ssautil.AllFunctions(prog)
+
+	// Check that all non-synthetic functions have distinct names.
+	byName := make(map[string]*ssa.Function)
+	for fn := range allFuncs {
+		if fn.Synthetic == "" {
+			str := fn.String()
+			prev := byName[str]
+			byName[str] = fn
+			if prev != nil {
+				t.Errorf("%s: duplicate function named %s",
+					prog.Fset.Position(fn.Pos()), str)
+				t.Errorf("%s:   (previously defined here)",
+					prog.Fset.Position(prev.Pos()))
+			}
+		}
+	}
+
+	// Dump some statistics.
 	var numInstrs int
 	for fn := range allFuncs {
 		for _, b := range fn.Blocks {

oracle/testdata/src/main/callgraph-json.golden

@@ -44,7 +44,7 @@
 			"pos": "testdata/src/main/callgraph-json.go:9:6"
 		},
 		{
-			"name": "main$1",
+			"name": "main.main$1",
 			"pos": "testdata/src/main/callgraph-json.go:31:8"
 		}
 	]

oracle/testdata/src/main/callgraph.golden

@@ -31,7 +31,7 @@ Non-numbered nodes indicate back- or cross-edges to the node whose
 6	            main.A
 7	            main.B
 8	        main.call2
-9	            main$1
+9	            main.main$1
 	        main.main (3)
 10	        main.nop
 

oracle/testdata/src/main/calls-json.golden

@@ -6,7 +6,7 @@
 		"desc": "dynamic function call",
 		"callees": [
 			{
-				"name": "main$1",
+				"name": "main.main$1",
 				"pos": "testdata/src/main/calls-json.go:12:7"
 			}
 		]
@@ -16,7 +16,7 @@
 	"mode": "callstack",
 	"callstack": {
 		"pos": "testdata/src/main/calls-json.go:12:7",
-		"target": "main$1",
+		"target": "main.main$1",
 		"callers": [
 			{
 				"pos": "testdata/src/main/calls-json.go:8:3",

oracle/testdata/src/main/calls.golden

@@ -35,11 +35,11 @@ main.store is called from these 2 sites:
 
 -------- @pointsto pointsto-result-f --------
 this func() *int may point to these objects:
-	main$1
+	main.main$1
 
 -------- @callees callees-main.call-f --------
 this dynamic function call dispatches to:
-	main$1
+	main.main$1
 
 -------- @callers callers-main.call --------
 main.call is called from these 2 sites:
@@ -103,7 +103,7 @@ main.init is called from these 1 sites:
 the root of the call graph
 
 -------- @callstack callstack-init --------
-Found a call path from root to main.init$1
-main.init$1
+Found a call path from root to main.init#1
+main.init#1
 static function call from main.init
 

oracle/testdata/src/main/pointsto.golden

@@ -29,7 +29,7 @@ this func() may point to these objects:
 
 -------- @pointsto ref-anon --------
 this func() may point to these objects:
-	main$1
+	pointsto.main$1
 
 -------- @pointsto ref-global --------
 this *string may point to these objects: