1// Derived from Inferno utils/6l/l.h and related files.
2// https://bitbucket.org/inferno-os/inferno-os/src/default/utils/6l/l.h
3//
4//	Copyright © 1994-1999 Lucent Technologies Inc.  All rights reserved.
5//	Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
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 (forsyth@terzarima.net)
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/obj"
36	"cmd/internal/objabi"
37	"cmd/internal/sys"
38	"cmd/link/internal/loader"
39	"cmd/link/internal/sym"
40	"debug/elf"
41	"fmt"
42)
43
44type Shlib struct {
45	Path            string
46	Hash            []byte
47	Deps            []string
48	File            *elf.File
49	gcdataAddresses map[*sym.Symbol]uint64
50}
51
52// Link holds the context for writing object code from a compiler
53// or for reading that input into the linker.
54type Link struct {
55	Out *OutBuf
56
57	Syms *sym.Symbols
58
59	Arch      *sys.Arch
60	Debugvlog int
61	Bso       *bufio.Writer
62
63	Loaded bool // set after all inputs have been loaded as symbols
64
65	IsELF    bool
66	HeadType objabi.HeadType
67
68	linkShared    bool // link against installed Go shared libraries
69	LinkMode      LinkMode
70	BuildMode     BuildMode
71	canUsePlugins bool // initialized when Loaded is set to true
72	compressDWARF bool
73
74	Tlsg         *sym.Symbol
75	Libdir       []string
76	Library      []*sym.Library
77	LibraryByPkg map[string]*sym.Library
78	Shlibs       []Shlib
79	Tlsoffset    int
80	Textp        []*sym.Symbol
81	Filesyms     []*sym.Symbol
82	Moduledata   *sym.Symbol
83
84	PackageFile  map[string]string
85	PackageShlib map[string]string
86
87	tramps []*sym.Symbol // trampolines
88
89	// unresolvedSymSet is a set of erroneous unresolved references.
90	// Used to avoid duplicated error messages.
91	unresolvedSymSet map[unresolvedSymKey]bool
92
93	// Used to implement field tracking.
94	Reachparent map[*sym.Symbol]*sym.Symbol
95
96	compUnits []*sym.CompilationUnit // DWARF compilation units
97	runtimeCU *sym.CompilationUnit   // One of the runtime CUs, the last one seen.
98
99	relocbuf []byte // temporary buffer for applying relocations
100
101	loader  *loader.Loader
102	cgodata []cgodata // cgo directives to load, three strings are args for loadcgo
103
104	cgo_export_static  map[string]bool
105	cgo_export_dynamic map[string]bool
106}
107
108type cgodata struct {
109	file       string
110	pkg        string
111	directives [][]string
112}
113
114type unresolvedSymKey struct {
115	from *sym.Symbol // Symbol that referenced unresolved "to"
116	to   *sym.Symbol // Unresolved symbol referenced by "from"
117}
118
119// ErrorUnresolved prints unresolved symbol error for r.Sym that is referenced from s.
120func (ctxt *Link) ErrorUnresolved(s *sym.Symbol, r *sym.Reloc) {
121	if ctxt.unresolvedSymSet == nil {
122		ctxt.unresolvedSymSet = make(map[unresolvedSymKey]bool)
123	}
124
125	k := unresolvedSymKey{from: s, to: r.Sym}
126	if !ctxt.unresolvedSymSet[k] {
127		ctxt.unresolvedSymSet[k] = true
128
129		// Try to find symbol under another ABI.
130		var reqABI, haveABI obj.ABI
131		haveABI = ^obj.ABI(0)
132		reqABI, ok := sym.VersionToABI(int(r.Sym.Version))
133		if ok {
134			for abi := obj.ABI(0); abi < obj.ABICount; abi++ {
135				v := sym.ABIToVersion(abi)
136				if v == -1 {
137					continue
138				}
139				if rs := ctxt.Syms.ROLookup(r.Sym.Name, v); rs != nil && rs.Type != sym.Sxxx {
140					haveABI = abi
141				}
142			}
143		}
144
145		// Give a special error message for main symbol (see #24809).
146		if r.Sym.Name == "main.main" {
147			Errorf(s, "function main is undeclared in the main package")
148		} else if haveABI != ^obj.ABI(0) {
149			Errorf(s, "relocation target %s not defined for %s (but is defined for %s)", r.Sym.Name, reqABI, haveABI)
150		} else {
151			Errorf(s, "relocation target %s not defined", r.Sym.Name)
152		}
153	}
154}
155
156// The smallest possible offset from the hardware stack pointer to a local
157// variable on the stack. Architectures that use a link register save its value
158// on the stack in the function prologue and so always have a pointer between
159// the hardware stack pointer and the local variable area.
160func (ctxt *Link) FixedFrameSize() int64 {
161	switch ctxt.Arch.Family {
162	case sys.AMD64, sys.I386:
163		return 0
164	case sys.PPC64:
165		// PIC code on ppc64le requires 32 bytes of stack, and it's easier to
166		// just use that much stack always on ppc64x.
167		return int64(4 * ctxt.Arch.PtrSize)
168	default:
169		return int64(ctxt.Arch.PtrSize)
170	}
171}
172
173func (ctxt *Link) Logf(format string, args ...interface{}) {
174	fmt.Fprintf(ctxt.Bso, format, args...)
175	ctxt.Bso.Flush()
176}
177
178func addImports(ctxt *Link, l *sym.Library, pn string) {
179	pkg := objabi.PathToPrefix(l.Pkg)
180	for _, importStr := range l.ImportStrings {
181		lib := addlib(ctxt, pkg, pn, importStr)
182		if lib != nil {
183			l.Imports = append(l.Imports, lib)
184		}
185	}
186	l.ImportStrings = nil
187}
188