diff options
Diffstat (limited to 'vendor/github.com/google/gops/internal/obj/pcln.go')
| -rw-r--r-- | vendor/github.com/google/gops/internal/obj/pcln.go | 281 |
1 files changed, 0 insertions, 281 deletions
diff --git a/vendor/github.com/google/gops/internal/obj/pcln.go b/vendor/github.com/google/gops/internal/obj/pcln.go deleted file mode 100644 index d9893e42..00000000 --- a/vendor/github.com/google/gops/internal/obj/pcln.go +++ /dev/null @@ -1,281 +0,0 @@ -// Copyright 2013 The Go Authors. All rights reserved. -// Use of this source code is governed by a BSD-style -// license that can be found in the LICENSE file. - -package obj - -import "log" - -func addvarint(ctxt *Link, d *Pcdata, val uint32) { - var v uint32 - for v = val; v >= 0x80; v >>= 7 { - d.P = append(d.P, uint8(v|0x80)) - } - d.P = append(d.P, uint8(v)) -} - -// funcpctab writes to dst a pc-value table mapping the code in func to the values -// returned by valfunc parameterized by arg. The invocation of valfunc to update the -// current value is, for each p, -// -// val = valfunc(func, val, p, 0, arg); -// record val as value at p->pc; -// val = valfunc(func, val, p, 1, arg); -// -// where func is the function, val is the current value, p is the instruction being -// considered, and arg can be used to further parameterize valfunc. -func funcpctab(ctxt *Link, dst *Pcdata, func_ *LSym, desc string, valfunc func(*Link, *LSym, int32, *Prog, int32, interface{}) int32, arg interface{}) { - // To debug a specific function, uncomment lines and change name. - dbg := 0 - - //if func_.Name == "main.main" || desc == "pctospadj" { - // dbg = 1 - //} - - ctxt.Debugpcln += int32(dbg) - - dst.P = dst.P[:0] - - if ctxt.Debugpcln != 0 { - ctxt.Logf("funcpctab %s [valfunc=%s]\n", func_.Name, desc) - } - - val := int32(-1) - oldval := val - if func_.Text == nil { - ctxt.Debugpcln -= int32(dbg) - return - } - - pc := func_.Text.Pc - - if ctxt.Debugpcln != 0 { - ctxt.Logf("%6x %6d %v\n", uint64(pc), val, func_.Text) - } - - started := int32(0) - var delta uint32 - for p := func_.Text; p != nil; p = p.Link { - // Update val. If it's not changing, keep going. - val = valfunc(ctxt, func_, val, p, 0, arg) - - if val == oldval && started != 0 { - val = valfunc(ctxt, func_, val, p, 1, arg) - if ctxt.Debugpcln != 0 { - ctxt.Logf("%6x %6s %v\n", uint64(p.Pc), "", p) - } - continue - } - - // If the pc of the next instruction is the same as the - // pc of this instruction, this instruction is not a real - // instruction. Keep going, so that we only emit a delta - // for a true instruction boundary in the program. - if p.Link != nil && p.Link.Pc == p.Pc { - val = valfunc(ctxt, func_, val, p, 1, arg) - if ctxt.Debugpcln != 0 { - ctxt.Logf("%6x %6s %v\n", uint64(p.Pc), "", p) - } - continue - } - - // The table is a sequence of (value, pc) pairs, where each - // pair states that the given value is in effect from the current position - // up to the given pc, which becomes the new current position. - // To generate the table as we scan over the program instructions, - // we emit a "(value" when pc == func->value, and then - // each time we observe a change in value we emit ", pc) (value". - // When the scan is over, we emit the closing ", pc)". - // - // The table is delta-encoded. The value deltas are signed and - // transmitted in zig-zag form, where a complement bit is placed in bit 0, - // and the pc deltas are unsigned. Both kinds of deltas are sent - // as variable-length little-endian base-128 integers, - // where the 0x80 bit indicates that the integer continues. - - if ctxt.Debugpcln != 0 { - ctxt.Logf("%6x %6d %v\n", uint64(p.Pc), val, p) - } - - if started != 0 { - addvarint(ctxt, dst, uint32((p.Pc-pc)/int64(ctxt.Arch.MinLC))) - pc = p.Pc - } - - delta = uint32(val) - uint32(oldval) - if delta>>31 != 0 { - delta = 1 | ^(delta << 1) - } else { - delta <<= 1 - } - addvarint(ctxt, dst, delta) - oldval = val - started = 1 - val = valfunc(ctxt, func_, val, p, 1, arg) - } - - if started != 0 { - if ctxt.Debugpcln != 0 { - ctxt.Logf("%6x done\n", uint64(func_.Text.Pc+func_.Size)) - } - addvarint(ctxt, dst, uint32((func_.Size-pc)/int64(ctxt.Arch.MinLC))) - addvarint(ctxt, dst, 0) // terminator - } - - if ctxt.Debugpcln != 0 { - ctxt.Logf("wrote %d bytes to %p\n", len(dst.P), dst) - for i := 0; i < len(dst.P); i++ { - ctxt.Logf(" %02x", dst.P[i]) - } - ctxt.Logf("\n") - } - - ctxt.Debugpcln -= int32(dbg) -} - -// pctofileline computes either the file number (arg == 0) -// or the line number (arg == 1) to use at p. -// Because p->lineno applies to p, phase == 0 (before p) -// takes care of the update. -func pctofileline(ctxt *Link, sym *LSym, oldval int32, p *Prog, phase int32, arg interface{}) int32 { - if p.As == ATEXT || p.As == ANOP || p.As == AUSEFIELD || p.Lineno == 0 || phase == 1 { - return oldval - } - f, l := linkgetline(ctxt, p.Lineno) - if f == nil { - // print("getline failed for %s %v\n", ctxt->cursym->name, p); - return oldval - } - - if arg == nil { - return l - } - pcln := arg.(*Pcln) - - if f == pcln.Lastfile { - return int32(pcln.Lastindex) - } - - for i, file := range pcln.File { - if file == f { - pcln.Lastfile = f - pcln.Lastindex = i - return int32(i) - } - } - i := len(pcln.File) - pcln.File = append(pcln.File, f) - pcln.Lastfile = f - pcln.Lastindex = i - return int32(i) -} - -// pctospadj computes the sp adjustment in effect. -// It is oldval plus any adjustment made by p itself. -// The adjustment by p takes effect only after p, so we -// apply the change during phase == 1. -func pctospadj(ctxt *Link, sym *LSym, oldval int32, p *Prog, phase int32, arg interface{}) int32 { - if oldval == -1 { // starting - oldval = 0 - } - if phase == 0 { - return oldval - } - if oldval+p.Spadj < -10000 || oldval+p.Spadj > 1100000000 { - ctxt.Diag("overflow in spadj: %d + %d = %d", oldval, p.Spadj, oldval+p.Spadj) - log.Fatalf("bad code") - } - - return oldval + p.Spadj -} - -// pctopcdata computes the pcdata value in effect at p. -// A PCDATA instruction sets the value in effect at future -// non-PCDATA instructions. -// Since PCDATA instructions have no width in the final code, -// it does not matter which phase we use for the update. -func pctopcdata(ctxt *Link, sym *LSym, oldval int32, p *Prog, phase int32, arg interface{}) int32 { - if phase == 0 || p.As != APCDATA || p.From.Offset != int64(arg.(uint32)) { - return oldval - } - if int64(int32(p.To.Offset)) != p.To.Offset { - ctxt.Diag("overflow in PCDATA instruction: %v", p) - log.Fatalf("bad code") - } - - return int32(p.To.Offset) -} - -func linkpcln(ctxt *Link, cursym *LSym) { - ctxt.Cursym = cursym - - pcln := new(Pcln) - cursym.Pcln = pcln - - npcdata := 0 - nfuncdata := 0 - for p := cursym.Text; p != nil; p = p.Link { - // Find the highest ID of any used PCDATA table. This ignores PCDATA table - // that consist entirely of "-1", since that's the assumed default value. - // From.Offset is table ID - // To.Offset is data - if p.As == APCDATA && p.From.Offset >= int64(npcdata) && p.To.Offset != -1 { // ignore -1 as we start at -1, if we only see -1, nothing changed - npcdata = int(p.From.Offset + 1) - } - // Find the highest ID of any FUNCDATA table. - // From.Offset is table ID - if p.As == AFUNCDATA && p.From.Offset >= int64(nfuncdata) { - nfuncdata = int(p.From.Offset + 1) - } - } - - pcln.Pcdata = make([]Pcdata, npcdata) - pcln.Pcdata = pcln.Pcdata[:npcdata] - pcln.Funcdata = make([]*LSym, nfuncdata) - pcln.Funcdataoff = make([]int64, nfuncdata) - pcln.Funcdataoff = pcln.Funcdataoff[:nfuncdata] - - funcpctab(ctxt, &pcln.Pcsp, cursym, "pctospadj", pctospadj, nil) - funcpctab(ctxt, &pcln.Pcfile, cursym, "pctofile", pctofileline, pcln) - funcpctab(ctxt, &pcln.Pcline, cursym, "pctoline", pctofileline, nil) - - // tabulate which pc and func data we have. - havepc := make([]uint32, (npcdata+31)/32) - havefunc := make([]uint32, (nfuncdata+31)/32) - for p := cursym.Text; p != nil; p = p.Link { - if p.As == AFUNCDATA { - if (havefunc[p.From.Offset/32]>>uint64(p.From.Offset%32))&1 != 0 { - ctxt.Diag("multiple definitions for FUNCDATA $%d", p.From.Offset) - } - havefunc[p.From.Offset/32] |= 1 << uint64(p.From.Offset%32) - } - - if p.As == APCDATA && p.To.Offset != -1 { - havepc[p.From.Offset/32] |= 1 << uint64(p.From.Offset%32) - } - } - - // pcdata. - for i := 0; i < npcdata; i++ { - if (havepc[i/32]>>uint(i%32))&1 == 0 { - continue - } - funcpctab(ctxt, &pcln.Pcdata[i], cursym, "pctopcdata", pctopcdata, interface{}(uint32(i))) - } - - // funcdata - if nfuncdata > 0 { - var i int - for p := cursym.Text; p != nil; p = p.Link { - if p.As == AFUNCDATA { - i = int(p.From.Offset) - pcln.Funcdataoff[i] = p.To.Offset - if p.To.Type != TYPE_CONST { - // TODO: Dedup. - //funcdata_bytes += p->to.sym->size; - pcln.Funcdata[i] = p.To.Sym - } - } - } - } -} |