github.com/cockroachdb/tools@v0.0.0-20230222021103-a6d27438930d/go/callgraph/static/static.go (about)

     1  // Copyright 2014 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // Package static computes the call graph of a Go program containing
     6  // only static call edges.
     7  package static // import "golang.org/x/tools/go/callgraph/static"
     8  
     9  // TODO(zpavlinovic): update static for how it handles generic function bodies.
    10  
    11  import (
    12  	"golang.org/x/tools/go/callgraph"
    13  	"golang.org/x/tools/go/ssa"
    14  	"golang.org/x/tools/go/ssa/ssautil"
    15  )
    16  
    17  // CallGraph computes the call graph of the specified program
    18  // considering only static calls.
    19  func CallGraph(prog *ssa.Program) *callgraph.Graph {
    20  	cg := callgraph.New(nil) // TODO(adonovan) eliminate concept of rooted callgraph
    21  
    22  	// TODO(adonovan): opt: use only a single pass over the ssa.Program.
    23  	// TODO(adonovan): opt: this is slower than RTA (perhaps because
    24  	// the lower precision means so many edges are allocated)!
    25  	for f := range ssautil.AllFunctions(prog) {
    26  		fnode := cg.CreateNode(f)
    27  		for _, b := range f.Blocks {
    28  			for _, instr := range b.Instrs {
    29  				if site, ok := instr.(ssa.CallInstruction); ok {
    30  					if g := site.Common().StaticCallee(); g != nil {
    31  						gnode := cg.CreateNode(g)
    32  						callgraph.AddEdge(fnode, site, gnode)
    33  					}
    34  				}
    35  			}
    36  		}
    37  	}
    38  
    39  	return cg
    40  }