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Diffstat (limited to 'src/cmd/link/internal/ld/link.go')
| -rw-r--r-- | src/cmd/link/internal/ld/link.go | 161 |
1 files changed, 161 insertions, 0 deletions
diff --git a/src/cmd/link/internal/ld/link.go b/src/cmd/link/internal/ld/link.go new file mode 100644 index 0000000..34221df --- /dev/null +++ b/src/cmd/link/internal/ld/link.go @@ -0,0 +1,161 @@ +// Derived from Inferno utils/6l/l.h and related files. +// https://bitbucket.org/inferno-os/inferno-os/src/master/utils/6l/l.h +// +// Copyright © 1994-1999 Lucent Technologies Inc. All rights reserved. +// Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net) +// Portions Copyright © 1997-1999 Vita Nuova Limited +// Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com) +// Portions Copyright © 2004,2006 Bruce Ellis +// Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net) +// Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others +// Portions Copyright © 2009 The Go Authors. All rights reserved. +// +// Permission is hereby granted, free of charge, to any person obtaining a copy +// of this software and associated documentation files (the "Software"), to deal +// in the Software without restriction, including without limitation the rights +// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell +// copies of the Software, and to permit persons to whom the Software is +// furnished to do so, subject to the following conditions: +// +// The above copyright notice and this permission notice shall be included in +// all copies or substantial portions of the Software. +// +// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN +// THE SOFTWARE. + +package ld + +import ( + "bufio" + "cmd/internal/objabi" + "cmd/link/internal/loader" + "cmd/link/internal/sym" + "debug/elf" + "fmt" +) + +type Shlib struct { + Path string + Hash []byte + Deps []string + File *elf.File +} + +// Link holds the context for writing object code from a compiler +// or for reading that input into the linker. +type Link struct { + Target + ErrorReporter + ArchSyms + + outSem chan int // limits the number of output writers + Out *OutBuf + + version int // current version number for static/file-local symbols + + Debugvlog int + Bso *bufio.Writer + + Loaded bool // set after all inputs have been loaded as symbols + + compressDWARF bool + + Libdir []string + Library []*sym.Library + LibraryByPkg map[string]*sym.Library + Shlibs []Shlib + Textp []loader.Sym + Moduledata loader.Sym + + PackageFile map[string]string + PackageShlib map[string]string + + tramps []loader.Sym // trampolines + + compUnits []*sym.CompilationUnit // DWARF compilation units + runtimeCU *sym.CompilationUnit // One of the runtime CUs, the last one seen. + + loader *loader.Loader + cgodata []cgodata // cgo directives to load, three strings are args for loadcgo + + datap []loader.Sym + dynexp []loader.Sym + + // Elf symtab variables. + numelfsym int // starts at 0, 1 is reserved + + // These are symbols that created and written by the linker. + // Rather than creating a symbol, and writing all its data into the heap, + // you can create a symbol, and just a generation function will be called + // after the symbol's been created in the output mmap. + generatorSyms map[loader.Sym]generatorFunc +} + +type cgodata struct { + file string + pkg string + directives [][]string +} + +func (ctxt *Link) Logf(format string, args ...interface{}) { + fmt.Fprintf(ctxt.Bso, format, args...) + ctxt.Bso.Flush() +} + +func addImports(ctxt *Link, l *sym.Library, pn string) { + pkg := objabi.PathToPrefix(l.Pkg) + for _, imp := range l.Autolib { + lib := addlib(ctxt, pkg, pn, imp.Pkg, imp.Fingerprint) + if lib != nil { + l.Imports = append(l.Imports, lib) + } + } + l.Autolib = nil +} + +// Allocate a new version (i.e. symbol namespace). +func (ctxt *Link) IncVersion() int { + ctxt.version++ + return ctxt.version - 1 +} + +// returns the maximum version number +func (ctxt *Link) MaxVersion() int { + return ctxt.version +} + +// generatorFunc is a convenience type. +// Some linker-created Symbols are large and shouldn't really live in the heap. +// Such Symbols can define a generator function. Their bytes can be generated +// directly in the output mmap. +// +// Relocations are applied prior to emitting generator Symbol contents. +// Generator Symbols that require relocations can be written in two passes. +// The first pass, at Symbol creation time, adds only relocations. +// The second pass, at content generation time, adds the rest. +// See generateFunctab for an example. +// +// Generator functions shouldn't grow the Symbol size. +// Generator functions must be safe for concurrent use. +// +// Generator Symbols have their Data set to the mmapped area when the +// generator is called. +type generatorFunc func(*Link, loader.Sym) + +// createGeneratorSymbol is a convenience method for creating a generator +// symbol. +func (ctxt *Link) createGeneratorSymbol(name string, version int, t sym.SymKind, size int64, gen generatorFunc) loader.Sym { + ldr := ctxt.loader + s := ldr.LookupOrCreateSym(name, version) + ldr.SetIsGeneratedSym(s, true) + sb := ldr.MakeSymbolUpdater(s) + sb.SetType(t) + sb.SetSize(size) + ctxt.generatorSyms[s] = gen + return s +} |