diff options
Diffstat (limited to 'vendor/golang.org/x/tools/go/callgraph/cha')
| -rw-r--r-- | vendor/golang.org/x/tools/go/callgraph/cha/cha.go | 164 |
1 files changed, 0 insertions, 164 deletions
diff --git a/vendor/golang.org/x/tools/go/callgraph/cha/cha.go b/vendor/golang.org/x/tools/go/callgraph/cha/cha.go deleted file mode 100644 index 3040f3d..0000000 --- a/vendor/golang.org/x/tools/go/callgraph/cha/cha.go +++ /dev/null @@ -1,164 +0,0 @@ -// Copyright 2014 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 cha computes the call graph of a Go program using the Class -// Hierarchy Analysis (CHA) algorithm. -// -// CHA was first described in "Optimization of Object-Oriented Programs -// Using Static Class Hierarchy Analysis", Jeffrey Dean, David Grove, -// and Craig Chambers, ECOOP'95. -// -// CHA is related to RTA (see go/callgraph/rta); the difference is that -// CHA conservatively computes the entire "implements" relation between -// interfaces and concrete types ahead of time, whereas RTA uses dynamic -// programming to construct it on the fly as it encounters new functions -// reachable from main. CHA may thus include spurious call edges for -// types that haven't been instantiated yet, or types that are never -// instantiated. -// -// Since CHA conservatively assumes that all functions are address-taken -// and all concrete types are put into interfaces, it is sound to run on -// partial programs, such as libraries without a main or test function. -package cha // import "golang.org/x/tools/go/callgraph/cha" - -// TODO(zpavlinovic): update CHA for how it handles generic function bodies. - -import ( - "go/types" - - "golang.org/x/tools/go/callgraph" - "golang.org/x/tools/go/ssa" - "golang.org/x/tools/go/ssa/ssautil" - "golang.org/x/tools/go/types/typeutil" -) - -// CallGraph computes the call graph of the specified program using the -// Class Hierarchy Analysis algorithm. -func CallGraph(prog *ssa.Program) *callgraph.Graph { - cg := callgraph.New(nil) // TODO(adonovan) eliminate concept of rooted callgraph - - allFuncs := ssautil.AllFunctions(prog) - - calleesOf := lazyCallees(allFuncs) - - addEdge := func(fnode *callgraph.Node, site ssa.CallInstruction, g *ssa.Function) { - gnode := cg.CreateNode(g) - callgraph.AddEdge(fnode, site, gnode) - } - - addEdges := func(fnode *callgraph.Node, site ssa.CallInstruction, callees []*ssa.Function) { - // Because every call to a highly polymorphic and - // frequently used abstract method such as - // (io.Writer).Write is assumed to call every concrete - // Write method in the program, the call graph can - // contain a lot of duplication. - // - // TODO(taking): opt: consider making lazyCallees public. - // Using the same benchmarks as callgraph_test.go, removing just - // the explicit callgraph.Graph construction is 4x less memory - // and is 37% faster. - // CHA 86 ms/op 16 MB/op - // lazyCallees 63 ms/op 4 MB/op - for _, g := range callees { - addEdge(fnode, site, g) - } - } - - for f := range allFuncs { - fnode := cg.CreateNode(f) - for _, b := range f.Blocks { - for _, instr := range b.Instrs { - if site, ok := instr.(ssa.CallInstruction); ok { - if g := site.Common().StaticCallee(); g != nil { - addEdge(fnode, site, g) - } else { - addEdges(fnode, site, calleesOf(site)) - } - } - } - } - } - - return cg -} - -// lazyCallees returns a function that maps a call site (in a function in fns) -// to its callees within fns. -// -// The resulting function is not concurrency safe. -func lazyCallees(fns map[*ssa.Function]bool) func(site ssa.CallInstruction) []*ssa.Function { - // funcsBySig contains all functions, keyed by signature. It is - // the effective set of address-taken functions used to resolve - // a dynamic call of a particular signature. - var funcsBySig typeutil.Map // value is []*ssa.Function - - // methodsByID contains all methods, grouped by ID for efficient - // lookup. - // - // We must key by ID, not name, for correct resolution of interface - // calls to a type with two (unexported) methods spelled the same but - // from different packages. The fact that the concrete type implements - // the interface does not mean the call dispatches to both methods. - methodsByID := make(map[string][]*ssa.Function) - - // An imethod represents an interface method I.m. - // (There's no go/types object for it; - // a *types.Func may be shared by many interfaces due to interface embedding.) - type imethod struct { - I *types.Interface - id string - } - // methodsMemo records, for every abstract method call I.m on - // interface type I, the set of concrete methods C.m of all - // types C that satisfy interface I. - // - // Abstract methods may be shared by several interfaces, - // hence we must pass I explicitly, not guess from m. - // - // methodsMemo is just a cache, so it needn't be a typeutil.Map. - methodsMemo := make(map[imethod][]*ssa.Function) - lookupMethods := func(I *types.Interface, m *types.Func) []*ssa.Function { - id := m.Id() - methods, ok := methodsMemo[imethod{I, id}] - if !ok { - for _, f := range methodsByID[id] { - C := f.Signature.Recv().Type() // named or *named - if types.Implements(C, I) { - methods = append(methods, f) - } - } - methodsMemo[imethod{I, id}] = methods - } - return methods - } - - for f := range fns { - if f.Signature.Recv() == nil { - // Package initializers can never be address-taken. - if f.Name() == "init" && f.Synthetic == "package initializer" { - continue - } - funcs, _ := funcsBySig.At(f.Signature).([]*ssa.Function) - funcs = append(funcs, f) - funcsBySig.Set(f.Signature, funcs) - } else if obj := f.Object(); obj != nil { - id := obj.(*types.Func).Id() - methodsByID[id] = append(methodsByID[id], f) - } - } - - return func(site ssa.CallInstruction) []*ssa.Function { - call := site.Common() - if call.IsInvoke() { - tiface := call.Value.Type().Underlying().(*types.Interface) - return lookupMethods(tiface, call.Method) - } else if g := call.StaticCallee(); g != nil { - return []*ssa.Function{g} - } else if _, ok := call.Value.(*ssa.Builtin); !ok { - fns, _ := funcsBySig.At(call.Signature()).([]*ssa.Function) - return fns - } - return nil - } -} |