1// Derived from Inferno utils/6l/l.h and related files.
2// https://bitbucket.org/inferno-os/inferno-os/src/master/utils/6l/l.h
3//
4//	Copyright © 1994-1999 Lucent Technologies Inc.  All rights reserved.
5//	Portions Copyright © 1995-1997 C H Forsyth ([email protected])
6//	Portions Copyright © 1997-1999 Vita Nuova Limited
7//	Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
8//	Portions Copyright © 2004,2006 Bruce Ellis
9//	Portions Copyright © 2005-2007 C H Forsyth ([email protected])
10//	Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
11//	Portions Copyright © 2009 The Go Authors. All rights reserved.
12//
13// Permission is hereby granted, free of charge, to any person obtaining a copy
14// of this software and associated documentation files (the "Software"), to deal
15// in the Software without restriction, including without limitation the rights
16// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
17// copies of the Software, and to permit persons to whom the Software is
18// furnished to do so, subject to the following conditions:
19//
20// The above copyright notice and this permission notice shall be included in
21// all copies or substantial portions of the Software.
22//
23// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
24// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
25// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
26// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
27// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
28// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
29// THE SOFTWARE.
30
31package ld
32
33import (
34	"bufio"
35	"cmd/internal/objabi"
36	"cmd/link/internal/loader"
37	"cmd/link/internal/sym"
38	"debug/elf"
39	"fmt"
40)
41
42type Shlib struct {
43	Path string
44	Hash []byte
45	Deps []string
46	File *elf.File
47}
48
49// Link holds the context for writing object code from a compiler
50// or for reading that input into the linker.
51type Link struct {
52	Target
53	ErrorReporter
54	ArchSyms
55
56	outSem chan int // limits the number of output writers
57	Out    *OutBuf
58
59	version int // current version number for static/file-local symbols
60
61	Debugvlog int
62	Bso       *bufio.Writer
63
64	Loaded bool // set after all inputs have been loaded as symbols
65
66	compressDWARF bool
67
68	Libdir       []string
69	Library      []*sym.Library
70	LibraryByPkg map[string]*sym.Library
71	Shlibs       []Shlib
72	Textp        []loader.Sym
73	Moduledata   loader.Sym
74
75	PackageFile  map[string]string
76	PackageShlib map[string]string
77
78	tramps []loader.Sym // trampolines
79
80	compUnits []*sym.CompilationUnit // DWARF compilation units
81	runtimeCU *sym.CompilationUnit   // One of the runtime CUs, the last one seen.
82
83	loader  *loader.Loader
84	cgodata []cgodata // cgo directives to load, three strings are args for loadcgo
85
86	datap  []loader.Sym
87	dynexp []loader.Sym
88
89	// Elf symtab variables.
90	numelfsym int // starts at 0, 1 is reserved
91
92	// These are symbols that created and written by the linker.
93	// Rather than creating a symbol, and writing all its data into the heap,
94	// you can create a symbol, and just a generation function will be called
95	// after the symbol's been created in the output mmap.
96	generatorSyms map[loader.Sym]generatorFunc
97}
98
99type cgodata struct {
100	file       string
101	pkg        string
102	directives [][]string
103}
104
105func (ctxt *Link) Logf(format string, args ...interface{}) {
106	fmt.Fprintf(ctxt.Bso, format, args...)
107	ctxt.Bso.Flush()
108}
109
110func addImports(ctxt *Link, l *sym.Library, pn string) {
111	pkg := objabi.PathToPrefix(l.Pkg)
112	for _, imp := range l.Autolib {
113		lib := addlib(ctxt, pkg, pn, imp.Pkg, imp.Fingerprint)
114		if lib != nil {
115			l.Imports = append(l.Imports, lib)
116		}
117	}
118	l.Autolib = nil
119}
120
121// Allocate a new version (i.e. symbol namespace).
122func (ctxt *Link) IncVersion() int {
123	ctxt.version++
124	return ctxt.version - 1
125}
126
127// returns the maximum version number
128func (ctxt *Link) MaxVersion() int {
129	return ctxt.version
130}
131
132// generatorFunc is a convenience type.
133// Some linker-created Symbols are large and shouldn't really live in the heap.
134// Such Symbols can define a generator function. Their bytes can be generated
135// directly in the output mmap.
136//
137// Relocations are applied prior to emitting generator Symbol contents.
138// Generator Symbols that require relocations can be written in two passes.
139// The first pass, at Symbol creation time, adds only relocations.
140// The second pass, at content generation time, adds the rest.
141// See generateFunctab for an example.
142//
143// Generator functions shouldn't grow the Symbol size.
144// Generator functions must be safe for concurrent use.
145//
146// Generator Symbols have their Data set to the mmapped area when the
147// generator is called.
148type generatorFunc func(*Link, loader.Sym)
149
150// createGeneratorSymbol is a convenience method for creating a generator
151// symbol.
152func (ctxt *Link) createGeneratorSymbol(name string, version int, t sym.SymKind, size int64, gen generatorFunc) loader.Sym {
153	ldr := ctxt.loader
154	s := ldr.LookupOrCreateSym(name, version)
155	ldr.SetIsGeneratedSym(s, true)
156	sb := ldr.MakeSymbolUpdater(s)
157	sb.SetType(t)
158	sb.SetSize(size)
159	ctxt.generatorSyms[s] = gen
160	return s
161}
162