[CI] Add more checks (#43)

vendor/honnef.co/go/tools/ssa/ssautil/visit.go

@@ -0,0 +1,79 @@
+// Copyright 2013 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 ssautil // import "honnef.co/go/tools/ssa/ssautil"
+
+import "honnef.co/go/tools/ssa"
+
+// This file defines utilities for visiting the SSA representation of
+// a Program.
+//
+// TODO(adonovan): test coverage.
+
+// AllFunctions finds and returns the set of functions potentially
+// needed by program prog, as determined by a simple linker-style
+// reachability algorithm starting from the members and method-sets of
+// each package.  The result may include anonymous functions and
+// synthetic wrappers.
+//
+// Precondition: all packages are built.
+//
+func AllFunctions(prog *ssa.Program) map[*ssa.Function]bool {
+	visit := visitor{
+		prog: prog,
+		seen: make(map[*ssa.Function]bool),
+	}
+	visit.program()
+	return visit.seen
+}
+
+type visitor struct {
+	prog *ssa.Program
+	seen map[*ssa.Function]bool
+}
+
+func (visit *visitor) program() {
+	for _, pkg := range visit.prog.AllPackages() {
+		for _, mem := range pkg.Members {
+			if fn, ok := mem.(*ssa.Function); ok {
+				visit.function(fn)
+			}
+		}
+	}
+	for _, T := range visit.prog.RuntimeTypes() {
+		mset := visit.prog.MethodSets.MethodSet(T)
+		for i, n := 0, mset.Len(); i < n; i++ {
+			visit.function(visit.prog.MethodValue(mset.At(i)))
+		}
+	}
+}
+
+func (visit *visitor) function(fn *ssa.Function) {
+	if !visit.seen[fn] {
+		visit.seen[fn] = true
+		var buf [10]*ssa.Value // avoid alloc in common case
+		for _, b := range fn.Blocks {
+			for _, instr := range b.Instrs {
+				for _, op := range instr.Operands(buf[:0]) {
+					if fn, ok := (*op).(*ssa.Function); ok {
+						visit.function(fn)
+					}
+				}
+			}
+		}
+	}
+}
+
+// MainPackages returns the subset of the specified packages
+// named "main" that define a main function.
+// The result may include synthetic "testmain" packages.
+func MainPackages(pkgs []*ssa.Package) []*ssa.Package {
+	var mains []*ssa.Package
+	for _, pkg := range pkgs {
+		if pkg.Pkg.Name() == "main" && pkg.Func("main") != nil {
+			mains = append(mains, pkg)
+		}
+	}
+	return mains
+}