load.go

Documentation: golang.org/x/tools/go/ssa/ssautil

     1  // Copyright 2015 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 ssautil
     6  
     7  // This file defines utility functions for constructing programs in SSA form.
     8  
     9  import (
    10  	"go/ast"
    11  	"go/token"
    12  	"go/types"
    13  
    14  	"golang.org/x/tools/go/loader"
    15  	"golang.org/x/tools/go/packages"
    16  	"golang.org/x/tools/go/ssa"
    17  	"golang.org/x/tools/internal/typeparams"
    18  )
    19  
    20  // Packages creates an SSA program for a set of packages.
    21  //
    22  // The packages must have been loaded from source syntax using the
    23  // golang.org/x/tools/go/packages.Load function in LoadSyntax or
    24  // LoadAllSyntax mode.
    25  //
    26  // Packages creates an SSA package for each well-typed package in the
    27  // initial list, plus all their dependencies. The resulting list of
    28  // packages corresponds to the list of initial packages, and may contain
    29  // a nil if SSA code could not be constructed for the corresponding initial
    30  // package due to type errors.
    31  //
    32  // Code for bodies of functions is not built until Build is called on
    33  // the resulting Program. SSA code is constructed only for the initial
    34  // packages with well-typed syntax trees.
    35  //
    36  // The mode parameter controls diagnostics and checking during SSA construction.
    37  func Packages(initial []*packages.Package, mode ssa.BuilderMode) (*ssa.Program, []*ssa.Package) {
    38  	return doPackages(initial, mode, false)
    39  }
    40  
    41  // AllPackages creates an SSA program for a set of packages plus all
    42  // their dependencies.
    43  //
    44  // The packages must have been loaded from source syntax using the
    45  // golang.org/x/tools/go/packages.Load function in LoadAllSyntax mode.
    46  //
    47  // AllPackages creates an SSA package for each well-typed package in the
    48  // initial list, plus all their dependencies. The resulting list of
    49  // packages corresponds to the list of initial packages, and may contain
    50  // a nil if SSA code could not be constructed for the corresponding
    51  // initial package due to type errors.
    52  //
    53  // Code for bodies of functions is not built until Build is called on
    54  // the resulting Program. SSA code is constructed for all packages with
    55  // well-typed syntax trees.
    56  //
    57  // The mode parameter controls diagnostics and checking during SSA construction.
    58  func AllPackages(initial []*packages.Package, mode ssa.BuilderMode) (*ssa.Program, []*ssa.Package) {
    59  	return doPackages(initial, mode, true)
    60  }
    61  
    62  func doPackages(initial []*packages.Package, mode ssa.BuilderMode, deps bool) (*ssa.Program, []*ssa.Package) {
    63  
    64  	var fset *token.FileSet
    65  	if len(initial) > 0 {
    66  		fset = initial[0].Fset
    67  	}
    68  
    69  	prog := ssa.NewProgram(fset, mode)
    70  
    71  	isInitial := make(map[*packages.Package]bool, len(initial))
    72  	for _, p := range initial {
    73  		isInitial[p] = true
    74  	}
    75  
    76  	ssamap := make(map[*packages.Package]*ssa.Package)
    77  	packages.Visit(initial, nil, func(p *packages.Package) {
    78  		if p.Types != nil && !p.IllTyped {
    79  			var files []*ast.File
    80  			var info *types.Info
    81  			if deps || isInitial[p] {
    82  				files = p.Syntax
    83  				info = p.TypesInfo
    84  			}
    85  			ssamap[p] = prog.CreatePackage(p.Types, files, info, true)
    86  		}
    87  	})
    88  
    89  	var ssapkgs []*ssa.Package
    90  	for _, p := range initial {
    91  		ssapkgs = append(ssapkgs, ssamap[p]) // may be nil
    92  	}
    93  	return prog, ssapkgs
    94  }
    95  
    96  // CreateProgram returns a new program in SSA form, given a program
    97  // loaded from source.  An SSA package is created for each transitively
    98  // error-free package of lprog.
    99  //
   100  // Code for bodies of functions is not built until Build is called
   101  // on the result.
   102  //
   103  // The mode parameter controls diagnostics and checking during SSA construction.
   104  //
   105  // Deprecated: Use golang.org/x/tools/go/packages and the Packages
   106  // function instead; see ssa.Example_loadPackages.
   107  func CreateProgram(lprog *loader.Program, mode ssa.BuilderMode) *ssa.Program {
   108  	prog := ssa.NewProgram(lprog.Fset, mode)
   109  
   110  	for _, info := range lprog.AllPackages {
   111  		if info.TransitivelyErrorFree {
   112  			prog.CreatePackage(info.Pkg, info.Files, &info.Info, info.Importable)
   113  		}
   114  	}
   115  
   116  	return prog
   117  }
   118  
   119  // BuildPackage builds an SSA program with IR for a single package.
   120  //
   121  // It populates pkg by type-checking the specified file ASTs.  All
   122  // dependencies are loaded using the importer specified by tc, which
   123  // typically loads compiler export data; SSA code cannot be built for
   124  // those packages.  BuildPackage then constructs an ssa.Program with all
   125  // dependency packages created, and builds and returns the SSA package
   126  // corresponding to pkg.
   127  //
   128  // The caller must have set pkg.Path() to the import path.
   129  //
   130  // The operation fails if there were any type-checking or import errors.
   131  //
   132  // See ../example_test.go for an example.
   133  func BuildPackage(tc *types.Config, fset *token.FileSet, pkg *types.Package, files []*ast.File, mode ssa.BuilderMode) (*ssa.Package, *types.Info, error) {
   134  	if fset == nil {
   135  		panic("no token.FileSet")
   136  	}
   137  	if pkg.Path() == "" {
   138  		panic("package has no import path")
   139  	}
   140  
   141  	info := &types.Info{
   142  		Types:      make(map[ast.Expr]types.TypeAndValue),
   143  		Defs:       make(map[*ast.Ident]types.Object),
   144  		Uses:       make(map[*ast.Ident]types.Object),
   145  		Implicits:  make(map[ast.Node]types.Object),
   146  		Scopes:     make(map[ast.Node]*types.Scope),
   147  		Selections: make(map[*ast.SelectorExpr]*types.Selection),
   148  	}
   149  	typeparams.InitInstanceInfo(info)
   150  	if err := types.NewChecker(tc, fset, pkg, info).Files(files); err != nil {
   151  		return nil, nil, err
   152  	}
   153  
   154  	prog := ssa.NewProgram(fset, mode)
   155  
   156  	// Create SSA packages for all imports.
   157  	// Order is not significant.
   158  	created := make(map[*types.Package]bool)
   159  	var createAll func(pkgs []*types.Package)
   160  	createAll = func(pkgs []*types.Package) {
   161  		for _, p := range pkgs {
   162  			if !created[p] {
   163  				created[p] = true
   164  				prog.CreatePackage(p, nil, nil, true)
   165  				createAll(p.Imports())
   166  			}
   167  		}
   168  	}
   169  	createAll(pkg.Imports())
   170  
   171  	// Create and build the primary package.
   172  	ssapkg := prog.CreatePackage(pkg, files, info, false)
   173  	ssapkg.Build()
   174  	return ssapkg, info, nil
   175  }
   176
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