[dev.link] cmd/link: clean up some pclntab state
Clean up some pclntab state, specifically:
1) Remove the oldPclnState type.
2) Move a structure out of pclnState, that was holding some memory.
3) Stop passing container around everywhere and calling emitPcln. Use a
slice of function symbols instead.
Change-Id: I74e916564cd769a706750d024e55ee0d811a79da
Reviewed-on: https://go-review.googlesource.com/c/go/+/248379
Run-TryBot: Jeremy Faller <jeremy@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
diff --git a/src/cmd/link/internal/ld/pcln.go b/src/cmd/link/internal/ld/pcln.go
index 576f1c3..33476ec 100644
--- a/src/cmd/link/internal/ld/pcln.go
+++ b/src/cmd/link/internal/ld/pcln.go
@@ -16,17 +16,6 @@
"strings"
)
-// oldPclnState holds state information used during pclntab generation. Here
-// 'ldr' is just a pointer to the context's loader, 'deferReturnSym' is the
-// index for the symbol "runtime.deferreturn",
-//
-// NB: This is deprecated, and will be eliminated when pclntab_old is
-// eliminated.
-type oldPclnState struct {
- ldr *loader.Loader
- deferReturnSym loader.Sym
-}
-
// pclntab holds the state needed for pclntab generation.
type pclntab struct {
// The first and last functions found.
@@ -56,12 +45,6 @@
// The number of filenames in runtime.filetab.
nfiles uint32
-
- // maps the function symbol to offset in runtime.funcnametab
- // This doesn't need to reside in the state once pclntab_old's been
- // deleted -- it can live in generateFuncnametab.
- // TODO(jfaller): Delete me!
- funcNameOffset map[loader.Sym]int32
}
// addGeneratedSym adds a generator symbol to pclntab, returning the new Sym.
@@ -76,35 +59,26 @@
return s
}
-func makeOldPclnState(ctxt *Link) *oldPclnState {
- ldr := ctxt.loader
- drs := ldr.Lookup("runtime.deferreturn", sym.SymVerABIInternal)
- state := &oldPclnState{
- ldr: ldr,
- deferReturnSym: drs,
- }
-
- return state
-}
-
// makePclntab makes a pclntab object, and assembles all the compilation units
-// we'll need to write pclntab.
-func makePclntab(ctxt *Link, container loader.Bitmap) (*pclntab, []*sym.CompilationUnit) {
+// we'll need to write pclntab. Returns the pclntab structure, a slice of the
+// CompilationUnits we need, and a slice of the function symbols we need to
+// generate pclntab.
+func makePclntab(ctxt *Link, container loader.Bitmap) (*pclntab, []*sym.CompilationUnit, []loader.Sym) {
ldr := ctxt.loader
- state := &pclntab{
- funcNameOffset: make(map[loader.Sym]int32),
- }
+ state := &pclntab{}
// Gather some basic stats and info.
seenCUs := make(map[*sym.CompilationUnit]struct{})
prevSect := ldr.SymSect(ctxt.Textp[0])
compUnits := []*sym.CompilationUnit{}
+ funcs := []loader.Sym{}
for _, s := range ctxt.Textp {
if !emitPcln(ctxt, s, container) {
continue
}
+ funcs = append(funcs, s)
state.nfunc++
if state.firstFunc == 0 {
state.firstFunc = s
@@ -130,15 +104,7 @@
compUnits = append(compUnits, cu)
}
}
- return state, compUnits
-}
-
-func ftabaddstring(ftab *loader.SymbolBuilder, s string) int32 {
- start := len(ftab.Data())
- ftab.Grow(int64(start + len(s) + 1)) // make room for s plus trailing NUL
- ftd := ftab.Data()
- copy(ftd[start:], s)
- return int32(start)
+ return state, compUnits, funcs
}
// onlycsymbol looks at a symbol's name to report whether this is a
@@ -163,11 +129,13 @@
return !container.Has(s)
}
-func (state *oldPclnState) computeDeferReturn(target *Target, s loader.Sym) uint32 {
+func computeDeferReturn(ctxt *Link, deferReturnSym, s loader.Sym) uint32 {
+ ldr := ctxt.loader
+ target := ctxt.Target
deferreturn := uint32(0)
lastWasmAddr := uint32(0)
- relocs := state.ldr.Relocs(s)
+ relocs := ldr.Relocs(s)
for ri := 0; ri < relocs.Count(); ri++ {
r := relocs.At(ri)
if target.IsWasm() && r.Type() == objabi.R_ADDR {
@@ -178,7 +146,7 @@
// set the resumption point to PC_B.
lastWasmAddr = uint32(r.Add())
}
- if r.Type().IsDirectCall() && (r.Sym() == state.deferReturnSym || state.ldr.IsDeferReturnTramp(r.Sym())) {
+ if r.Type().IsDirectCall() && (r.Sym() == deferReturnSym || ldr.IsDeferReturnTramp(r.Sym())) {
if target.IsWasm() {
deferreturn = lastWasmAddr - 1
} else {
@@ -211,8 +179,8 @@
// genInlTreeSym generates the InlTree sym for a function with the
// specified FuncInfo.
-func (state *oldPclnState) genInlTreeSym(cu *sym.CompilationUnit, fi loader.FuncInfo, arch *sys.Arch, newState *pclntab) loader.Sym {
- ldr := state.ldr
+func genInlTreeSym(ctxt *Link, cu *sym.CompilationUnit, fi loader.FuncInfo, arch *sys.Arch, nameOffsets map[loader.Sym]uint32) loader.Sym {
+ ldr := ctxt.loader
its := ldr.CreateExtSym("", 0)
inlTreeSym := ldr.MakeSymbolUpdater(its)
// Note: the generated symbol is given a type of sym.SGOFUNC, as a
@@ -225,7 +193,7 @@
for i := 0; i < int(ninl); i++ {
call := fi.InlTree(i)
val := call.File
- nameoff, ok := newState.funcNameOffset[call.Func]
+ nameoff, ok := nameOffsets[call.Func]
if !ok {
panic("couldn't find function name offset")
}
@@ -282,16 +250,12 @@
state.pcheader = state.addGeneratedSym(ctxt, "runtime.pcheader", size, writeHeader)
}
-// walkFuncs iterates over the Textp, calling a function for each unique
+// walkFuncs iterates over the funcs, calling a function for each unique
// function and inlined function.
-func (state *pclntab) walkFuncs(ctxt *Link, container loader.Bitmap, f func(loader.Sym)) {
+func walkFuncs(ctxt *Link, funcs []loader.Sym, f func(loader.Sym)) {
ldr := ctxt.loader
seen := make(map[loader.Sym]struct{})
- for _, ls := range ctxt.Textp {
- s := loader.Sym(ls)
- if !emitPcln(ctxt, s, container) {
- continue
- }
+ for _, s := range funcs {
if _, ok := seen[s]; !ok {
f(s)
seen[s] = struct{}{}
@@ -312,37 +276,37 @@
}
}
-// generateFuncnametab creates the function name table.
-func (state *pclntab) generateFuncnametab(ctxt *Link, container loader.Bitmap) {
+// generateFuncnametab creates the function name table. Returns a map of
+// func symbol to the name offset in runtime.funcnamtab.
+func (state *pclntab) generateFuncnametab(ctxt *Link, funcs []loader.Sym) map[loader.Sym]uint32 {
+ nameOffsets := make(map[loader.Sym]uint32, state.nfunc)
+
// Write the null terminated strings.
writeFuncNameTab := func(ctxt *Link, s loader.Sym) {
symtab := ctxt.loader.MakeSymbolUpdater(s)
- for s, off := range state.funcNameOffset {
+ for s, off := range nameOffsets {
symtab.AddStringAt(int64(off), ctxt.loader.SymName(s))
}
}
// Loop through the CUs, and calculate the size needed.
var size int64
- state.walkFuncs(ctxt, container, func(s loader.Sym) {
- state.funcNameOffset[s] = int32(size)
+ walkFuncs(ctxt, funcs, func(s loader.Sym) {
+ nameOffsets[s] = uint32(size)
size += int64(ctxt.loader.SymNameLen(s)) + 1 // NULL terminate
})
state.funcnametab = state.addGeneratedSym(ctxt, "runtime.funcnametab", size, writeFuncNameTab)
+ return nameOffsets
}
-// walkFilenames walks the filenames in the all reachable functions.
-func walkFilenames(ctxt *Link, container loader.Bitmap, f func(*sym.CompilationUnit, goobj.CUFileIndex)) {
+// walkFilenames walks funcs, calling a function for each filename used in each
+// function's line table.
+func walkFilenames(ctxt *Link, funcs []loader.Sym, f func(*sym.CompilationUnit, goobj.CUFileIndex)) {
ldr := ctxt.loader
// Loop through all functions, finding the filenames we need.
- for _, ls := range ctxt.Textp {
- s := loader.Sym(ls)
- if !emitPcln(ctxt, s, container) {
- continue
- }
-
+ for _, s := range funcs {
fi := ldr.FuncInfo(s)
if !fi.Valid() {
continue
@@ -382,7 +346,7 @@
// 1) Get Func.CUIndex: M := func.cuOffset
// 2) Find filename offset: fileOffset := runtime.cutab[M+K]
// 3) Get the filename: getcstring(runtime.filetab[fileOffset])
-func (state *pclntab) generateFilenameTabs(ctxt *Link, compUnits []*sym.CompilationUnit, container loader.Bitmap) []uint32 {
+func (state *pclntab) generateFilenameTabs(ctxt *Link, compUnits []*sym.CompilationUnit, funcs []loader.Sym) []uint32 {
// On a per-CU basis, keep track of all the filenames we need.
//
// Note, that we store the filenames in a separate section in the object
@@ -402,7 +366,7 @@
// file index we've seen per CU so we can calculate how large the
// CU->global table needs to be.
var fileSize int64
- walkFilenames(ctxt, container, func(cu *sym.CompilationUnit, i goobj.CUFileIndex) {
+ walkFilenames(ctxt, funcs, func(cu *sym.CompilationUnit, i goobj.CUFileIndex) {
// Note we use the raw filename for lookup, but use the expanded filename
// when we save the size.
filename := cu.FileTable[i]
@@ -467,7 +431,7 @@
// generatePctab creates the runtime.pctab variable, holding all the
// deduplicated pcdata.
-func (state *pclntab) generatePctab(ctxt *Link, container loader.Bitmap) {
+func (state *pclntab) generatePctab(ctxt *Link, funcs []loader.Sym) {
ldr := ctxt.loader
// Pctab offsets of 0 are considered invalid in the runtime. We respect
@@ -490,10 +454,7 @@
seen[pcSym] = struct{}{}
}
}
- for _, s := range ctxt.Textp {
- if !emitPcln(ctxt, s, container) {
- continue
- }
+ for _, s := range funcs {
fi := ldr.FuncInfo(s)
if !fi.Valid() {
continue
@@ -566,8 +527,7 @@
// end PC [thearch.ptrsize bytes]
// func structures, pcdata tables.
- oldState := makeOldPclnState(ctxt)
- state, compUnits := makePclntab(ctxt, container)
+ state, compUnits, funcs := makePclntab(ctxt, container)
ldr := ctxt.loader
state.carrier = ldr.LookupOrCreateSym("runtime.pclntab", 0)
@@ -579,9 +539,12 @@
// rational form.
state.pclntab = ldr.LookupOrCreateSym("runtime.pclntab_old", 0)
state.generatePCHeader(ctxt)
- state.generateFuncnametab(ctxt, container)
- cuOffsets := state.generateFilenameTabs(ctxt, compUnits, container)
- state.generatePctab(ctxt, container)
+ nameOffsets := state.generateFuncnametab(ctxt, funcs)
+ cuOffsets := state.generateFilenameTabs(ctxt, compUnits, funcs)
+ state.generatePctab(ctxt, funcs)
+
+ // Used to when computing defer return.
+ deferReturnSym := ldr.Lookup("runtime.deferreturn", sym.SymVerABIInternal)
funcdataBytes := int64(0)
ldr.SetCarrierSym(state.pclntab, state.carrier)
@@ -613,11 +576,7 @@
var nfunc int32
prevFunc := ctxt.Textp[0]
- for _, s := range ctxt.Textp {
- if !emitPcln(ctxt, s, container) {
- continue
- }
-
+ for _, s := range funcs {
thisSect := ldr.SymSect(s)
prevSect := ldr.SymSect(prevFunc)
if thisSect != prevSect {
@@ -686,7 +645,7 @@
off = int32(setAddr(ftab, ctxt.Arch, int64(off), s, 0))
// name int32
- nameoff, ok := state.funcNameOffset[s]
+ nameoff, ok := nameOffsets[s]
if !ok {
panic("couldn't find function name offset")
}
@@ -701,13 +660,13 @@
off = int32(ftab.SetUint32(ctxt.Arch, int64(off), args))
// deferreturn
- deferreturn := oldState.computeDeferReturn(&ctxt.Target, s)
+ deferreturn := computeDeferReturn(ctxt, deferReturnSym, s)
off = int32(ftab.SetUint32(ctxt.Arch, int64(off), deferreturn))
cu := ldr.SymUnit(s)
if fi.Valid() && fi.NumInlTree() > 0 {
- its := oldState.genInlTreeSym(cu, fi, ctxt.Arch, state)
+ its := genInlTreeSym(ctxt, cu, fi, ctxt.Arch, nameOffsets)
funcdata[objabi.FUNCDATA_InlTree] = its
}
