cmd/link: pre-resolve package reference
Pre-resolve package index references, so it doesn't need to do a
map lookup in every cross-package symbol reference resolution. It
increases the memory usage very slightly (O(# imported packages)).
Change-Id: Ia76c97ac51f1c2c2d5ea7ae34853850ec69ef0a8
Reviewed-on: https://go-review.googlesource.com/c/go/+/253604
Run-TryBot: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
diff --git a/src/cmd/link/internal/loader/loader.go b/src/cmd/link/internal/loader/loader.go
index 8fd10b0..43a0352 100644
--- a/src/cmd/link/internal/loader/loader.go
+++ b/src/cmd/link/internal/loader/loader.go
@@ -93,11 +93,12 @@
version int // version of static symbol
flags uint32 // read from object file
pkgprefix string
- syms []Sym // Sym's global index, indexed by local index
- ndef int // cache goobj.Reader.NSym()
- nhashed64def int // cache goobj.Reader.NHashed64Def()
- nhasheddef int // cache goobj.Reader.NHashedDef()
- objidx uint32 // index of this reader in the objs slice
+ syms []Sym // Sym's global index, indexed by local index
+ pkg []uint32 // indices of referenced package by PkgIdx (index into loader.objs array)
+ ndef int // cache goobj.Reader.NSym()
+ nhashed64def int // cache goobj.Reader.NHashed64Def()
+ nhasheddef int // cache goobj.Reader.NHashedDef()
+ objidx uint32 // index of this reader in the objs slice
}
// Total number of defined symbols (package symbols, hashed symbols, and
@@ -219,7 +220,7 @@
deferReturnTramp map[Sym]bool // whether the symbol is a trampoline of a deferreturn call
- objByPkg map[string]*oReader // map package path to its Go object reader
+ objByPkg map[string]uint32 // map package path to the index of its Go object reader
anonVersion int // most recently assigned ext static sym pseudo-version
@@ -331,7 +332,7 @@
objSyms: make([]objSym, 1, 100000), // reserve index 0 for nil symbol
extReader: extReader,
symsByName: [2]map[string]Sym{make(map[string]Sym, 80000), make(map[string]Sym, 50000)}, // preallocate ~2MB for ABI0 and ~1MB for ABI1 symbols
- objByPkg: make(map[string]*oReader),
+ objByPkg: make(map[string]uint32),
outer: make(map[Sym]Sym),
sub: make(map[Sym]Sym),
dynimplib: make(map[Sym]string),
@@ -370,7 +371,7 @@
}
pkg = objabi.PathToPrefix(pkg) // the object file contains escaped package path
if _, ok := l.objByPkg[pkg]; !ok {
- l.objByPkg[pkg] = r
+ l.objByPkg[pkg] = r.objidx
}
i := Sym(len(l.objSyms))
l.start[r] = i
@@ -635,12 +636,7 @@
case goobj.PkgIdxSelf:
rr = r
default:
- pkg := r.Pkg(int(p))
- var ok bool
- rr, ok = l.objByPkg[pkg]
- if !ok {
- log.Fatalf("reference of nonexisted package %s, from %v", pkg, r.unit.Lib)
- }
+ rr = l.objs[r.pkg[p]].r
}
return l.toGlobal(rr, s.SymIdx)
}
@@ -2195,6 +2191,18 @@
}
}
+ // referenced packages
+ npkg := r.NPkg()
+ r.pkg = make([]uint32, npkg)
+ for i := 1; i < npkg; i++ { // PkgIdx 0 is a dummy invalid package
+ pkg := r.Pkg(i)
+ objidx, ok := l.objByPkg[pkg]
+ if !ok {
+ log.Fatalf("reference of nonexisted package %s, from %v", pkg, r.unit.Lib)
+ }
+ r.pkg[i] = objidx
+ }
+
// load flags of package refs
for i, n := 0, r.NRefFlags(); i < n; i++ {
rf := r.RefFlags(i)
