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[CI] Add more checks (#43)

This commit is contained in:
konrad
2018-12-28 22:15:05 +00:00
committed by Gitea
parent 3814b8a504
commit 018dd8164c
73 changed files with 16332 additions and 6 deletions

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// Copyright 2015 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
// This file defines utility functions for constructing programs in SSA form.
import (
"go/ast"
"go/token"
"go/types"
"golang.org/x/tools/go/loader"
"honnef.co/go/tools/ssa"
)
// CreateProgram returns a new program in SSA form, given a program
// loaded from source. An SSA package is created for each transitively
// error-free package of lprog.
//
// Code for bodies of functions is not built until Build is called
// on the result.
//
// mode controls diagnostics and checking during SSA construction.
//
func CreateProgram(lprog *loader.Program, mode ssa.BuilderMode) *ssa.Program {
prog := ssa.NewProgram(lprog.Fset, mode)
for _, info := range lprog.AllPackages {
if info.TransitivelyErrorFree {
prog.CreatePackage(info.Pkg, info.Files, &info.Info, info.Importable)
}
}
return prog
}
// BuildPackage builds an SSA program with IR for a single package.
//
// It populates pkg by type-checking the specified file ASTs. All
// dependencies are loaded using the importer specified by tc, which
// typically loads compiler export data; SSA code cannot be built for
// those packages. BuildPackage then constructs an ssa.Program with all
// dependency packages created, and builds and returns the SSA package
// corresponding to pkg.
//
// The caller must have set pkg.Path() to the import path.
//
// The operation fails if there were any type-checking or import errors.
//
// See ../ssa/example_test.go for an example.
//
func BuildPackage(tc *types.Config, fset *token.FileSet, pkg *types.Package, files []*ast.File, mode ssa.BuilderMode) (*ssa.Package, *types.Info, error) {
if fset == nil {
panic("no token.FileSet")
}
if pkg.Path() == "" {
panic("package has no import path")
}
info := &types.Info{
Types: make(map[ast.Expr]types.TypeAndValue),
Defs: make(map[*ast.Ident]types.Object),
Uses: make(map[*ast.Ident]types.Object),
Implicits: make(map[ast.Node]types.Object),
Scopes: make(map[ast.Node]*types.Scope),
Selections: make(map[*ast.SelectorExpr]*types.Selection),
}
if err := types.NewChecker(tc, fset, pkg, info).Files(files); err != nil {
return nil, nil, err
}
prog := ssa.NewProgram(fset, mode)
// Create SSA packages for all imports.
// Order is not significant.
created := make(map[*types.Package]bool)
var createAll func(pkgs []*types.Package)
createAll = func(pkgs []*types.Package) {
for _, p := range pkgs {
if !created[p] {
created[p] = true
prog.CreatePackage(p, nil, nil, true)
createAll(p.Imports())
}
}
}
createAll(pkg.Imports())
// Create and build the primary package.
ssapkg := prog.CreatePackage(pkg, files, info, false)
ssapkg.Build()
return ssapkg, info, nil
}

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// 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
// This file implements discovery of switch and type-switch constructs
// from low-level control flow.
//
// Many techniques exist for compiling a high-level switch with
// constant cases to efficient machine code. The optimal choice will
// depend on the data type, the specific case values, the code in the
// body of each case, and the hardware.
// Some examples:
// - a lookup table (for a switch that maps constants to constants)
// - a computed goto
// - a binary tree
// - a perfect hash
// - a two-level switch (to partition constant strings by their first byte).
import (
"bytes"
"fmt"
"go/token"
"go/types"
"honnef.co/go/tools/ssa"
)
// A ConstCase represents a single constant comparison.
// It is part of a Switch.
type ConstCase struct {
Block *ssa.BasicBlock // block performing the comparison
Body *ssa.BasicBlock // body of the case
Value *ssa.Const // case comparand
}
// A TypeCase represents a single type assertion.
// It is part of a Switch.
type TypeCase struct {
Block *ssa.BasicBlock // block performing the type assert
Body *ssa.BasicBlock // body of the case
Type types.Type // case type
Binding ssa.Value // value bound by this case
}
// A Switch is a logical high-level control flow operation
// (a multiway branch) discovered by analysis of a CFG containing
// only if/else chains. It is not part of the ssa.Instruction set.
//
// One of ConstCases and TypeCases has length >= 2;
// the other is nil.
//
// In a value switch, the list of cases may contain duplicate constants.
// A type switch may contain duplicate types, or types assignable
// to an interface type also in the list.
// TODO(adonovan): eliminate such duplicates.
//
type Switch struct {
Start *ssa.BasicBlock // block containing start of if/else chain
X ssa.Value // the switch operand
ConstCases []ConstCase // ordered list of constant comparisons
TypeCases []TypeCase // ordered list of type assertions
Default *ssa.BasicBlock // successor if all comparisons fail
}
func (sw *Switch) String() string {
// We represent each block by the String() of its
// first Instruction, e.g. "print(42:int)".
var buf bytes.Buffer
if sw.ConstCases != nil {
fmt.Fprintf(&buf, "switch %s {\n", sw.X.Name())
for _, c := range sw.ConstCases {
fmt.Fprintf(&buf, "case %s: %s\n", c.Value, c.Body.Instrs[0])
}
} else {
fmt.Fprintf(&buf, "switch %s.(type) {\n", sw.X.Name())
for _, c := range sw.TypeCases {
fmt.Fprintf(&buf, "case %s %s: %s\n",
c.Binding.Name(), c.Type, c.Body.Instrs[0])
}
}
if sw.Default != nil {
fmt.Fprintf(&buf, "default: %s\n", sw.Default.Instrs[0])
}
fmt.Fprintf(&buf, "}")
return buf.String()
}
// Switches examines the control-flow graph of fn and returns the
// set of inferred value and type switches. A value switch tests an
// ssa.Value for equality against two or more compile-time constant
// values. Switches involving link-time constants (addresses) are
// ignored. A type switch type-asserts an ssa.Value against two or
// more types.
//
// The switches are returned in dominance order.
//
// The resulting switches do not necessarily correspond to uses of the
// 'switch' keyword in the source: for example, a single source-level
// switch statement with non-constant cases may result in zero, one or
// many Switches, one per plural sequence of constant cases.
// Switches may even be inferred from if/else- or goto-based control flow.
// (In general, the control flow constructs of the source program
// cannot be faithfully reproduced from the SSA representation.)
//
func Switches(fn *ssa.Function) []Switch {
// Traverse the CFG in dominance order, so we don't
// enter an if/else-chain in the middle.
var switches []Switch
seen := make(map[*ssa.BasicBlock]bool) // TODO(adonovan): opt: use ssa.blockSet
for _, b := range fn.DomPreorder() {
if x, k := isComparisonBlock(b); x != nil {
// Block b starts a switch.
sw := Switch{Start: b, X: x}
valueSwitch(&sw, k, seen)
if len(sw.ConstCases) > 1 {
switches = append(switches, sw)
}
}
if y, x, T := isTypeAssertBlock(b); y != nil {
// Block b starts a type switch.
sw := Switch{Start: b, X: x}
typeSwitch(&sw, y, T, seen)
if len(sw.TypeCases) > 1 {
switches = append(switches, sw)
}
}
}
return switches
}
func valueSwitch(sw *Switch, k *ssa.Const, seen map[*ssa.BasicBlock]bool) {
b := sw.Start
x := sw.X
for x == sw.X {
if seen[b] {
break
}
seen[b] = true
sw.ConstCases = append(sw.ConstCases, ConstCase{
Block: b,
Body: b.Succs[0],
Value: k,
})
b = b.Succs[1]
if len(b.Instrs) > 2 {
// Block b contains not just 'if x == k',
// so it may have side effects that
// make it unsafe to elide.
break
}
if len(b.Preds) != 1 {
// Block b has multiple predecessors,
// so it cannot be treated as a case.
break
}
x, k = isComparisonBlock(b)
}
sw.Default = b
}
func typeSwitch(sw *Switch, y ssa.Value, T types.Type, seen map[*ssa.BasicBlock]bool) {
b := sw.Start
x := sw.X
for x == sw.X {
if seen[b] {
break
}
seen[b] = true
sw.TypeCases = append(sw.TypeCases, TypeCase{
Block: b,
Body: b.Succs[0],
Type: T,
Binding: y,
})
b = b.Succs[1]
if len(b.Instrs) > 4 {
// Block b contains not just
// {TypeAssert; Extract #0; Extract #1; If}
// so it may have side effects that
// make it unsafe to elide.
break
}
if len(b.Preds) != 1 {
// Block b has multiple predecessors,
// so it cannot be treated as a case.
break
}
y, x, T = isTypeAssertBlock(b)
}
sw.Default = b
}
// isComparisonBlock returns the operands (v, k) if a block ends with
// a comparison v==k, where k is a compile-time constant.
//
func isComparisonBlock(b *ssa.BasicBlock) (v ssa.Value, k *ssa.Const) {
if n := len(b.Instrs); n >= 2 {
if i, ok := b.Instrs[n-1].(*ssa.If); ok {
if binop, ok := i.Cond.(*ssa.BinOp); ok && binop.Block() == b && binop.Op == token.EQL {
if k, ok := binop.Y.(*ssa.Const); ok {
return binop.X, k
}
if k, ok := binop.X.(*ssa.Const); ok {
return binop.Y, k
}
}
}
}
return
}
// isTypeAssertBlock returns the operands (y, x, T) if a block ends with
// a type assertion "if y, ok := x.(T); ok {".
//
func isTypeAssertBlock(b *ssa.BasicBlock) (y, x ssa.Value, T types.Type) {
if n := len(b.Instrs); n >= 4 {
if i, ok := b.Instrs[n-1].(*ssa.If); ok {
if ext1, ok := i.Cond.(*ssa.Extract); ok && ext1.Block() == b && ext1.Index == 1 {
if ta, ok := ext1.Tuple.(*ssa.TypeAssert); ok && ta.Block() == b {
// hack: relies upon instruction ordering.
if ext0, ok := b.Instrs[n-3].(*ssa.Extract); ok {
return ext0, ta.X, ta.AssertedType
}
}
}
}
}
return
}

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// 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
}