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[dev.link] cmd/link: assign special indices for builtin functions

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Compiler-generated function references (e.g. call to
runtime.newobject) appear frequently. We assign special indices
for them, so they don't need to be referenced by name.

Change-Id: I2072594cbc56c9e1037a26e4aae12e68c2436e9f
Reviewed-on: https://go-review.googlesource.com/c/go/+/202085
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
This commit is contained in:
Cherry Zhang 2019-10-18 17:08:35 -04:00
parent df01b7968b
commit fb06609817
6 changed files with 391 additions and 7 deletions
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21
src/cmd/link/internal/loader/loader.go
View file

@ -91,11 +91,12 @@ func makeBitmap(n int) bitmap {
// A Loader loads new object files and resolves indexed symbol references.
type Loader struct {
start map[*oReader]Sym // map from object file to its start index
objs []objIdx // sorted by start index (i.e. objIdx.i)
max Sym // current max index
extStart Sym // from this index on, the symbols are externally defined
extSyms []nameVer // externally defined symbols
start map[*oReader]Sym // map from object file to its start index
objs []objIdx // sorted by start index (i.e. objIdx.i)
max Sym // current max index
extStart Sym // from this index on, the symbols are externally defined
extSyms []nameVer // externally defined symbols
builtinSyms []Sym // global index of builtin symbols
symsByName [2]map[string]Sym // map symbol name to index, two maps are for ABI0 and ABIInternal
extStaticSyms map[nameVer]Sym // externally defined static symbols, keyed by name
@ -111,6 +112,7 @@ type Loader struct {
}
func NewLoader() *Loader {
nbuiltin := goobj2.NBuiltin()
return &Loader{
start: make(map[*oReader]Sym),
objs: []objIdx{{nil, 0}},
@ -119,6 +121,7 @@ func NewLoader() *Loader {
overwrite: make(map[Sym]Sym),
itablink: make(map[Sym]struct{}),
extStaticSyms: make(map[nameVer]Sym),
builtinSyms: make([]Sym, nbuiltin),
}
}
@ -272,7 +275,7 @@ func (l *Loader) resolve(r *oReader, s goobj2.SymRef) Sym {
v := abiToVer(osym.ABI, r.version)
return l.Lookup(name, v)
case goobj2.PkgIdxBuiltin:
panic("PkgIdxBuiltin not used")
return l.builtinSyms[s.SymIdx]
case goobj2.PkgIdxSelf:
rr = r
default:
@ -575,6 +578,12 @@ func (l *Loader) Preload(arch *sys.Arch, syms *sym.Symbols, f *bio.Reader, lib *
if added && strings.HasPrefix(name, "go.itablink.") {
l.itablink[istart+Sym(i)] = struct{}{}
}
if added && strings.HasPrefix(name, "runtime.") {
if bi := goobj2.BuiltinIdx(name, v); bi != -1 {
// This is a definition of a builtin symbol. Record where it is.
l.builtinSyms[bi] = istart + Sym(i)
}
}
}
// The caller expects us consuming all the data