mirror of
https://github.com/cwinfo/matterbridge.git
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1482 lines
35 KiB
Go
1482 lines
35 KiB
Go
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// Inferno utils/6l/pass.c
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// https://bitbucket.org/inferno-os/inferno-os/src/default/utils/6l/pass.c
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//
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// Copyright © 1994-1999 Lucent Technologies Inc. All rights reserved.
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// Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
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// Portions Copyright © 1997-1999 Vita Nuova Limited
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// Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
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// Portions Copyright © 2004,2006 Bruce Ellis
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// Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
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// Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
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// Portions Copyright © 2009 The Go Authors. All rights reserved.
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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// THE SOFTWARE.
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package x86
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import (
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"fmt"
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"log"
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"math"
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"strings"
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"github.com/google/gops/internal/obj"
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"github.com/google/gops/internal/sys"
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)
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func CanUse1InsnTLS(ctxt *obj.Link) bool {
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if isAndroid {
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// For android, we use a disgusting hack that assumes
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// the thread-local storage slot for g is allocated
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// using pthread_key_create with a fixed offset
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// (see src/runtime/cgo/gcc_android_amd64.c).
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// This makes access to the TLS storage (for g) doable
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// with 1 instruction.
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return true
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}
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if ctxt.Arch.RegSize == 4 {
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switch ctxt.Headtype {
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case obj.Hlinux,
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obj.Hnacl,
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obj.Hplan9,
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obj.Hwindows,
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obj.Hwindowsgui:
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return false
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}
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return true
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}
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switch ctxt.Headtype {
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case obj.Hplan9, obj.Hwindows, obj.Hwindowsgui:
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return false
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case obj.Hlinux:
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return !ctxt.Flag_shared
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}
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return true
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}
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func progedit(ctxt *obj.Link, p *obj.Prog) {
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// Maintain information about code generation mode.
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if ctxt.Mode == 0 {
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ctxt.Mode = ctxt.Arch.RegSize * 8
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}
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p.Mode = int8(ctxt.Mode)
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switch p.As {
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case AMODE:
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if p.From.Type == obj.TYPE_CONST || (p.From.Type == obj.TYPE_MEM && p.From.Reg == REG_NONE) {
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switch int(p.From.Offset) {
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case 16, 32, 64:
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ctxt.Mode = int(p.From.Offset)
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}
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}
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obj.Nopout(p)
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}
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// Thread-local storage references use the TLS pseudo-register.
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// As a register, TLS refers to the thread-local storage base, and it
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// can only be loaded into another register:
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//
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// MOVQ TLS, AX
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//
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// An offset from the thread-local storage base is written off(reg)(TLS*1).
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// Semantically it is off(reg), but the (TLS*1) annotation marks this as
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// indexing from the loaded TLS base. This emits a relocation so that
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// if the linker needs to adjust the offset, it can. For example:
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//
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// MOVQ TLS, AX
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// MOVQ 0(AX)(TLS*1), CX // load g into CX
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//
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// On systems that support direct access to the TLS memory, this
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// pair of instructions can be reduced to a direct TLS memory reference:
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//
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// MOVQ 0(TLS), CX // load g into CX
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//
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// The 2-instruction and 1-instruction forms correspond to the two code
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// sequences for loading a TLS variable in the local exec model given in "ELF
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// Handling For Thread-Local Storage".
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//
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// We apply this rewrite on systems that support the 1-instruction form.
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// The decision is made using only the operating system and the -shared flag,
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// not the link mode. If some link modes on a particular operating system
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// require the 2-instruction form, then all builds for that operating system
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// will use the 2-instruction form, so that the link mode decision can be
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// delayed to link time.
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//
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// In this way, all supported systems use identical instructions to
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// access TLS, and they are rewritten appropriately first here in
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// liblink and then finally using relocations in the linker.
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//
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// When -shared is passed, we leave the code in the 2-instruction form but
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// assemble (and relocate) them in different ways to generate the initial
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// exec code sequence. It's a bit of a fluke that this is possible without
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// rewriting the instructions more comprehensively, and it only does because
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// we only support a single TLS variable (g).
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if CanUse1InsnTLS(ctxt) {
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// Reduce 2-instruction sequence to 1-instruction sequence.
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// Sequences like
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// MOVQ TLS, BX
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// ... off(BX)(TLS*1) ...
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// become
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// NOP
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// ... off(TLS) ...
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//
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// TODO(rsc): Remove the Hsolaris special case. It exists only to
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// guarantee we are producing byte-identical binaries as before this code.
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// But it should be unnecessary.
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if (p.As == AMOVQ || p.As == AMOVL) && p.From.Type == obj.TYPE_REG && p.From.Reg == REG_TLS && p.To.Type == obj.TYPE_REG && REG_AX <= p.To.Reg && p.To.Reg <= REG_R15 && ctxt.Headtype != obj.Hsolaris {
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obj.Nopout(p)
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}
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if p.From.Type == obj.TYPE_MEM && p.From.Index == REG_TLS && REG_AX <= p.From.Reg && p.From.Reg <= REG_R15 {
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p.From.Reg = REG_TLS
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p.From.Scale = 0
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p.From.Index = REG_NONE
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}
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if p.To.Type == obj.TYPE_MEM && p.To.Index == REG_TLS && REG_AX <= p.To.Reg && p.To.Reg <= REG_R15 {
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p.To.Reg = REG_TLS
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p.To.Scale = 0
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p.To.Index = REG_NONE
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}
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} else {
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// load_g_cx, below, always inserts the 1-instruction sequence. Rewrite it
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// as the 2-instruction sequence if necessary.
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// MOVQ 0(TLS), BX
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// becomes
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// MOVQ TLS, BX
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// MOVQ 0(BX)(TLS*1), BX
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if (p.As == AMOVQ || p.As == AMOVL) && p.From.Type == obj.TYPE_MEM && p.From.Reg == REG_TLS && p.To.Type == obj.TYPE_REG && REG_AX <= p.To.Reg && p.To.Reg <= REG_R15 {
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q := obj.Appendp(ctxt, p)
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q.As = p.As
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q.From = p.From
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q.From.Type = obj.TYPE_MEM
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q.From.Reg = p.To.Reg
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q.From.Index = REG_TLS
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q.From.Scale = 2 // TODO: use 1
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q.To = p.To
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p.From.Type = obj.TYPE_REG
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p.From.Reg = REG_TLS
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p.From.Index = REG_NONE
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p.From.Offset = 0
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}
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}
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// TODO: Remove.
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if (ctxt.Headtype == obj.Hwindows || ctxt.Headtype == obj.Hwindowsgui) && p.Mode == 64 || ctxt.Headtype == obj.Hplan9 {
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if p.From.Scale == 1 && p.From.Index == REG_TLS {
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p.From.Scale = 2
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}
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if p.To.Scale == 1 && p.To.Index == REG_TLS {
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p.To.Scale = 2
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}
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}
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// Rewrite 0 to $0 in 3rd argument to CMPPS etc.
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// That's what the tables expect.
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switch p.As {
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case ACMPPD, ACMPPS, ACMPSD, ACMPSS:
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if p.To.Type == obj.TYPE_MEM && p.To.Name == obj.NAME_NONE && p.To.Reg == REG_NONE && p.To.Index == REG_NONE && p.To.Sym == nil {
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p.To.Type = obj.TYPE_CONST
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}
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}
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// Rewrite CALL/JMP/RET to symbol as TYPE_BRANCH.
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switch p.As {
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case obj.ACALL, obj.AJMP, obj.ARET:
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if p.To.Type == obj.TYPE_MEM && (p.To.Name == obj.NAME_EXTERN || p.To.Name == obj.NAME_STATIC) && p.To.Sym != nil {
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p.To.Type = obj.TYPE_BRANCH
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}
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}
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// Rewrite MOVL/MOVQ $XXX(FP/SP) as LEAL/LEAQ.
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if p.From.Type == obj.TYPE_ADDR && (ctxt.Arch.Family == sys.AMD64 || p.From.Name != obj.NAME_EXTERN && p.From.Name != obj.NAME_STATIC) {
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switch p.As {
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case AMOVL:
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p.As = ALEAL
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p.From.Type = obj.TYPE_MEM
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case AMOVQ:
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p.As = ALEAQ
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p.From.Type = obj.TYPE_MEM
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}
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}
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if ctxt.Headtype == obj.Hnacl && p.Mode == 64 {
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if p.From3 != nil {
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nacladdr(ctxt, p, p.From3)
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}
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nacladdr(ctxt, p, &p.From)
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nacladdr(ctxt, p, &p.To)
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}
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// Rewrite float constants to values stored in memory.
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switch p.As {
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// Convert AMOVSS $(0), Xx to AXORPS Xx, Xx
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case AMOVSS:
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if p.From.Type == obj.TYPE_FCONST {
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// f == 0 can't be used here due to -0, so use Float64bits
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if f := p.From.Val.(float64); math.Float64bits(f) == 0 {
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if p.To.Type == obj.TYPE_REG && REG_X0 <= p.To.Reg && p.To.Reg <= REG_X15 {
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p.As = AXORPS
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p.From = p.To
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break
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}
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}
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}
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fallthrough
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case AFMOVF,
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AFADDF,
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AFSUBF,
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AFSUBRF,
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AFMULF,
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AFDIVF,
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AFDIVRF,
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AFCOMF,
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AFCOMFP,
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AADDSS,
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ASUBSS,
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AMULSS,
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ADIVSS,
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ACOMISS,
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AUCOMISS:
|
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if p.From.Type == obj.TYPE_FCONST {
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f32 := float32(p.From.Val.(float64))
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i32 := math.Float32bits(f32)
|
||
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literal := fmt.Sprintf("$f32.%08x", i32)
|
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s := obj.Linklookup(ctxt, literal, 0)
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p.From.Type = obj.TYPE_MEM
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p.From.Name = obj.NAME_EXTERN
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p.From.Sym = s
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||
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p.From.Sym.Set(obj.AttrLocal, true)
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p.From.Offset = 0
|
||
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}
|
||
|
|
||
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case AMOVSD:
|
||
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// Convert AMOVSD $(0), Xx to AXORPS Xx, Xx
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||
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if p.From.Type == obj.TYPE_FCONST {
|
||
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// f == 0 can't be used here due to -0, so use Float64bits
|
||
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if f := p.From.Val.(float64); math.Float64bits(f) == 0 {
|
||
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if p.To.Type == obj.TYPE_REG && REG_X0 <= p.To.Reg && p.To.Reg <= REG_X15 {
|
||
|
p.As = AXORPS
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p.From = p.To
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||
|
break
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
fallthrough
|
||
|
|
||
|
case AFMOVD,
|
||
|
AFADDD,
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|
AFSUBD,
|
||
|
AFSUBRD,
|
||
|
AFMULD,
|
||
|
AFDIVD,
|
||
|
AFDIVRD,
|
||
|
AFCOMD,
|
||
|
AFCOMDP,
|
||
|
AADDSD,
|
||
|
ASUBSD,
|
||
|
AMULSD,
|
||
|
ADIVSD,
|
||
|
ACOMISD,
|
||
|
AUCOMISD:
|
||
|
if p.From.Type == obj.TYPE_FCONST {
|
||
|
i64 := math.Float64bits(p.From.Val.(float64))
|
||
|
literal := fmt.Sprintf("$f64.%016x", i64)
|
||
|
s := obj.Linklookup(ctxt, literal, 0)
|
||
|
p.From.Type = obj.TYPE_MEM
|
||
|
p.From.Name = obj.NAME_EXTERN
|
||
|
p.From.Sym = s
|
||
|
p.From.Sym.Set(obj.AttrLocal, true)
|
||
|
p.From.Offset = 0
|
||
|
}
|
||
|
}
|
||
|
|
||
|
if ctxt.Flag_dynlink {
|
||
|
rewriteToUseGot(ctxt, p)
|
||
|
}
|
||
|
|
||
|
if ctxt.Flag_shared && p.Mode == 32 {
|
||
|
rewriteToPcrel(ctxt, p)
|
||
|
}
|
||
|
}
|
||
|
|
||
|
// Rewrite p, if necessary, to access global data via the global offset table.
|
||
|
func rewriteToUseGot(ctxt *obj.Link, p *obj.Prog) {
|
||
|
var add, lea, mov obj.As
|
||
|
var reg int16
|
||
|
if p.Mode == 64 {
|
||
|
add = AADDQ
|
||
|
lea = ALEAQ
|
||
|
mov = AMOVQ
|
||
|
reg = REG_R15
|
||
|
} else {
|
||
|
add = AADDL
|
||
|
lea = ALEAL
|
||
|
mov = AMOVL
|
||
|
reg = REG_CX
|
||
|
if p.As == ALEAL && p.To.Reg != p.From.Reg && p.To.Reg != p.From.Index {
|
||
|
// Special case: clobber the destination register with
|
||
|
// the PC so we don't have to clobber CX.
|
||
|
// The SSA backend depends on CX not being clobbered across LEAL.
|
||
|
// See cmd/compile/internal/ssa/gen/386.rules (search for Flag_shared).
|
||
|
reg = p.To.Reg
|
||
|
}
|
||
|
}
|
||
|
|
||
|
if p.As == obj.ADUFFCOPY || p.As == obj.ADUFFZERO {
|
||
|
// ADUFFxxx $offset
|
||
|
// becomes
|
||
|
// $MOV runtime.duffxxx@GOT, $reg
|
||
|
// $ADD $offset, $reg
|
||
|
// CALL $reg
|
||
|
var sym *obj.LSym
|
||
|
if p.As == obj.ADUFFZERO {
|
||
|
sym = obj.Linklookup(ctxt, "runtime.duffzero", 0)
|
||
|
} else {
|
||
|
sym = obj.Linklookup(ctxt, "runtime.duffcopy", 0)
|
||
|
}
|
||
|
offset := p.To.Offset
|
||
|
p.As = mov
|
||
|
p.From.Type = obj.TYPE_MEM
|
||
|
p.From.Name = obj.NAME_GOTREF
|
||
|
p.From.Sym = sym
|
||
|
p.To.Type = obj.TYPE_REG
|
||
|
p.To.Reg = reg
|
||
|
p.To.Offset = 0
|
||
|
p.To.Sym = nil
|
||
|
p1 := obj.Appendp(ctxt, p)
|
||
|
p1.As = add
|
||
|
p1.From.Type = obj.TYPE_CONST
|
||
|
p1.From.Offset = offset
|
||
|
p1.To.Type = obj.TYPE_REG
|
||
|
p1.To.Reg = reg
|
||
|
p2 := obj.Appendp(ctxt, p1)
|
||
|
p2.As = obj.ACALL
|
||
|
p2.To.Type = obj.TYPE_REG
|
||
|
p2.To.Reg = reg
|
||
|
}
|
||
|
|
||
|
// We only care about global data: NAME_EXTERN means a global
|
||
|
// symbol in the Go sense, and p.Sym.Local is true for a few
|
||
|
// internally defined symbols.
|
||
|
if p.As == lea && p.From.Type == obj.TYPE_MEM && p.From.Name == obj.NAME_EXTERN && !p.From.Sym.Local() {
|
||
|
// $LEA sym, Rx becomes $MOV $sym, Rx which will be rewritten below
|
||
|
p.As = mov
|
||
|
p.From.Type = obj.TYPE_ADDR
|
||
|
}
|
||
|
if p.From.Type == obj.TYPE_ADDR && p.From.Name == obj.NAME_EXTERN && !p.From.Sym.Local() {
|
||
|
// $MOV $sym, Rx becomes $MOV sym@GOT, Rx
|
||
|
// $MOV $sym+<off>, Rx becomes $MOV sym@GOT, Rx; $LEA <off>(Rx), Rx
|
||
|
// On 386 only, more complicated things like PUSHL $sym become $MOV sym@GOT, CX; PUSHL CX
|
||
|
cmplxdest := false
|
||
|
pAs := p.As
|
||
|
var dest obj.Addr
|
||
|
if p.To.Type != obj.TYPE_REG || pAs != mov {
|
||
|
if p.Mode == 64 {
|
||
|
ctxt.Diag("do not know how to handle LEA-type insn to non-register in %v with -dynlink", p)
|
||
|
}
|
||
|
cmplxdest = true
|
||
|
dest = p.To
|
||
|
p.As = mov
|
||
|
p.To.Type = obj.TYPE_REG
|
||
|
p.To.Reg = reg
|
||
|
p.To.Sym = nil
|
||
|
p.To.Name = obj.NAME_NONE
|
||
|
}
|
||
|
p.From.Type = obj.TYPE_MEM
|
||
|
p.From.Name = obj.NAME_GOTREF
|
||
|
q := p
|
||
|
if p.From.Offset != 0 {
|
||
|
q = obj.Appendp(ctxt, p)
|
||
|
q.As = lea
|
||
|
q.From.Type = obj.TYPE_MEM
|
||
|
q.From.Reg = p.To.Reg
|
||
|
q.From.Offset = p.From.Offset
|
||
|
q.To = p.To
|
||
|
p.From.Offset = 0
|
||
|
}
|
||
|
if cmplxdest {
|
||
|
q = obj.Appendp(ctxt, q)
|
||
|
q.As = pAs
|
||
|
q.To = dest
|
||
|
q.From.Type = obj.TYPE_REG
|
||
|
q.From.Reg = reg
|
||
|
}
|
||
|
}
|
||
|
if p.From3 != nil && p.From3.Name == obj.NAME_EXTERN {
|
||
|
ctxt.Diag("don't know how to handle %v with -dynlink", p)
|
||
|
}
|
||
|
var source *obj.Addr
|
||
|
// MOVx sym, Ry becomes $MOV sym@GOT, R15; MOVx (R15), Ry
|
||
|
// MOVx Ry, sym becomes $MOV sym@GOT, R15; MOVx Ry, (R15)
|
||
|
// An addition may be inserted between the two MOVs if there is an offset.
|
||
|
if p.From.Name == obj.NAME_EXTERN && !p.From.Sym.Local() {
|
||
|
if p.To.Name == obj.NAME_EXTERN && !p.To.Sym.Local() {
|
||
|
ctxt.Diag("cannot handle NAME_EXTERN on both sides in %v with -dynlink", p)
|
||
|
}
|
||
|
source = &p.From
|
||
|
} else if p.To.Name == obj.NAME_EXTERN && !p.To.Sym.Local() {
|
||
|
source = &p.To
|
||
|
} else {
|
||
|
return
|
||
|
}
|
||
|
if p.As == obj.ACALL {
|
||
|
// When dynlinking on 386, almost any call might end up being a call
|
||
|
// to a PLT, so make sure the GOT pointer is loaded into BX.
|
||
|
// RegTo2 is set on the replacement call insn to stop it being
|
||
|
// processed when it is in turn passed to progedit.
|
||
|
if p.Mode == 64 || (p.To.Sym != nil && p.To.Sym.Local()) || p.RegTo2 != 0 {
|
||
|
return
|
||
|
}
|
||
|
p1 := obj.Appendp(ctxt, p)
|
||
|
p2 := obj.Appendp(ctxt, p1)
|
||
|
|
||
|
p1.As = ALEAL
|
||
|
p1.From.Type = obj.TYPE_MEM
|
||
|
p1.From.Name = obj.NAME_STATIC
|
||
|
p1.From.Sym = obj.Linklookup(ctxt, "_GLOBAL_OFFSET_TABLE_", 0)
|
||
|
p1.To.Type = obj.TYPE_REG
|
||
|
p1.To.Reg = REG_BX
|
||
|
|
||
|
p2.As = p.As
|
||
|
p2.Scond = p.Scond
|
||
|
p2.From = p.From
|
||
|
p2.From3 = p.From3
|
||
|
p2.Reg = p.Reg
|
||
|
p2.To = p.To
|
||
|
// p.To.Type was set to TYPE_BRANCH above, but that makes checkaddr
|
||
|
// in ../pass.go complain, so set it back to TYPE_MEM here, until p2
|
||
|
// itself gets passed to progedit.
|
||
|
p2.To.Type = obj.TYPE_MEM
|
||
|
p2.RegTo2 = 1
|
||
|
|
||
|
obj.Nopout(p)
|
||
|
return
|
||
|
|
||
|
}
|
||
|
if p.As == obj.ATEXT || p.As == obj.AFUNCDATA || p.As == obj.ARET || p.As == obj.AJMP {
|
||
|
return
|
||
|
}
|
||
|
if source.Type != obj.TYPE_MEM {
|
||
|
ctxt.Diag("don't know how to handle %v with -dynlink", p)
|
||
|
}
|
||
|
p1 := obj.Appendp(ctxt, p)
|
||
|
p2 := obj.Appendp(ctxt, p1)
|
||
|
|
||
|
p1.As = mov
|
||
|
p1.From.Type = obj.TYPE_MEM
|
||
|
p1.From.Sym = source.Sym
|
||
|
p1.From.Name = obj.NAME_GOTREF
|
||
|
p1.To.Type = obj.TYPE_REG
|
||
|
p1.To.Reg = reg
|
||
|
|
||
|
p2.As = p.As
|
||
|
p2.From = p.From
|
||
|
p2.To = p.To
|
||
|
if p.From.Name == obj.NAME_EXTERN {
|
||
|
p2.From.Reg = reg
|
||
|
p2.From.Name = obj.NAME_NONE
|
||
|
p2.From.Sym = nil
|
||
|
} else if p.To.Name == obj.NAME_EXTERN {
|
||
|
p2.To.Reg = reg
|
||
|
p2.To.Name = obj.NAME_NONE
|
||
|
p2.To.Sym = nil
|
||
|
} else {
|
||
|
return
|
||
|
}
|
||
|
obj.Nopout(p)
|
||
|
}
|
||
|
|
||
|
func rewriteToPcrel(ctxt *obj.Link, p *obj.Prog) {
|
||
|
// RegTo2 is set on the instructions we insert here so they don't get
|
||
|
// processed twice.
|
||
|
if p.RegTo2 != 0 {
|
||
|
return
|
||
|
}
|
||
|
if p.As == obj.ATEXT || p.As == obj.AFUNCDATA || p.As == obj.ACALL || p.As == obj.ARET || p.As == obj.AJMP {
|
||
|
return
|
||
|
}
|
||
|
// Any Prog (aside from the above special cases) with an Addr with Name ==
|
||
|
// NAME_EXTERN, NAME_STATIC or NAME_GOTREF has a CALL __x86.get_pc_thunk.XX
|
||
|
// inserted before it.
|
||
|
isName := func(a *obj.Addr) bool {
|
||
|
if a.Sym == nil || (a.Type != obj.TYPE_MEM && a.Type != obj.TYPE_ADDR) || a.Reg != 0 {
|
||
|
return false
|
||
|
}
|
||
|
if a.Sym.Type == obj.STLSBSS {
|
||
|
return false
|
||
|
}
|
||
|
return a.Name == obj.NAME_EXTERN || a.Name == obj.NAME_STATIC || a.Name == obj.NAME_GOTREF
|
||
|
}
|
||
|
|
||
|
if isName(&p.From) && p.From.Type == obj.TYPE_ADDR {
|
||
|
// Handle things like "MOVL $sym, (SP)" or "PUSHL $sym" by rewriting
|
||
|
// to "MOVL $sym, CX; MOVL CX, (SP)" or "MOVL $sym, CX; PUSHL CX"
|
||
|
// respectively.
|
||
|
if p.To.Type != obj.TYPE_REG {
|
||
|
q := obj.Appendp(ctxt, p)
|
||
|
q.As = p.As
|
||
|
q.From.Type = obj.TYPE_REG
|
||
|
q.From.Reg = REG_CX
|
||
|
q.To = p.To
|
||
|
p.As = AMOVL
|
||
|
p.To.Type = obj.TYPE_REG
|
||
|
p.To.Reg = REG_CX
|
||
|
p.To.Sym = nil
|
||
|
p.To.Name = obj.NAME_NONE
|
||
|
}
|
||
|
}
|
||
|
|
||
|
if !isName(&p.From) && !isName(&p.To) && (p.From3 == nil || !isName(p.From3)) {
|
||
|
return
|
||
|
}
|
||
|
var dst int16 = REG_CX
|
||
|
if (p.As == ALEAL || p.As == AMOVL) && p.To.Reg != p.From.Reg && p.To.Reg != p.From.Index {
|
||
|
dst = p.To.Reg
|
||
|
// Why? See the comment near the top of rewriteToUseGot above.
|
||
|
// AMOVLs might be introduced by the GOT rewrites.
|
||
|
}
|
||
|
q := obj.Appendp(ctxt, p)
|
||
|
q.RegTo2 = 1
|
||
|
r := obj.Appendp(ctxt, q)
|
||
|
r.RegTo2 = 1
|
||
|
q.As = obj.ACALL
|
||
|
q.To.Sym = obj.Linklookup(ctxt, "__x86.get_pc_thunk."+strings.ToLower(Rconv(int(dst))), 0)
|
||
|
q.To.Type = obj.TYPE_MEM
|
||
|
q.To.Name = obj.NAME_EXTERN
|
||
|
q.To.Sym.Set(obj.AttrLocal, true)
|
||
|
r.As = p.As
|
||
|
r.Scond = p.Scond
|
||
|
r.From = p.From
|
||
|
r.From3 = p.From3
|
||
|
r.Reg = p.Reg
|
||
|
r.To = p.To
|
||
|
if isName(&p.From) {
|
||
|
r.From.Reg = dst
|
||
|
}
|
||
|
if isName(&p.To) {
|
||
|
r.To.Reg = dst
|
||
|
}
|
||
|
if p.From3 != nil && isName(p.From3) {
|
||
|
r.From3.Reg = dst
|
||
|
}
|
||
|
obj.Nopout(p)
|
||
|
}
|
||
|
|
||
|
func nacladdr(ctxt *obj.Link, p *obj.Prog, a *obj.Addr) {
|
||
|
if p.As == ALEAL || p.As == ALEAQ {
|
||
|
return
|
||
|
}
|
||
|
|
||
|
if a.Reg == REG_BP {
|
||
|
ctxt.Diag("invalid address: %v", p)
|
||
|
return
|
||
|
}
|
||
|
|
||
|
if a.Reg == REG_TLS {
|
||
|
a.Reg = REG_BP
|
||
|
}
|
||
|
if a.Type == obj.TYPE_MEM && a.Name == obj.NAME_NONE {
|
||
|
switch a.Reg {
|
||
|
// all ok
|
||
|
case REG_BP, REG_SP, REG_R15:
|
||
|
break
|
||
|
|
||
|
default:
|
||
|
if a.Index != REG_NONE {
|
||
|
ctxt.Diag("invalid address %v", p)
|
||
|
}
|
||
|
a.Index = a.Reg
|
||
|
if a.Index != REG_NONE {
|
||
|
a.Scale = 1
|
||
|
}
|
||
|
a.Reg = REG_R15
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
|
||
|
func preprocess(ctxt *obj.Link, cursym *obj.LSym) {
|
||
|
if ctxt.Headtype == obj.Hplan9 && ctxt.Plan9privates == nil {
|
||
|
ctxt.Plan9privates = obj.Linklookup(ctxt, "_privates", 0)
|
||
|
}
|
||
|
|
||
|
ctxt.Cursym = cursym
|
||
|
|
||
|
if cursym.Text == nil || cursym.Text.Link == nil {
|
||
|
return
|
||
|
}
|
||
|
|
||
|
p := cursym.Text
|
||
|
autoffset := int32(p.To.Offset)
|
||
|
if autoffset < 0 {
|
||
|
autoffset = 0
|
||
|
}
|
||
|
|
||
|
var bpsize int
|
||
|
if p.Mode == 64 && ctxt.Framepointer_enabled && autoffset > 0 && p.From3.Offset&obj.NOFRAME == 0 {
|
||
|
// Make room for to save a base pointer. If autoffset == 0,
|
||
|
// this might do something special like a tail jump to
|
||
|
// another function, so in that case we omit this.
|
||
|
bpsize = ctxt.Arch.PtrSize
|
||
|
autoffset += int32(bpsize)
|
||
|
p.To.Offset += int64(bpsize)
|
||
|
} else {
|
||
|
bpsize = 0
|
||
|
}
|
||
|
|
||
|
textarg := int64(p.To.Val.(int32))
|
||
|
cursym.Args = int32(textarg)
|
||
|
cursym.Locals = int32(p.To.Offset)
|
||
|
|
||
|
// TODO(rsc): Remove.
|
||
|
if p.Mode == 32 && cursym.Locals < 0 {
|
||
|
cursym.Locals = 0
|
||
|
}
|
||
|
|
||
|
// TODO(rsc): Remove 'p.Mode == 64 &&'.
|
||
|
if p.Mode == 64 && autoffset < obj.StackSmall && p.From3Offset()&obj.NOSPLIT == 0 {
|
||
|
leaf := true
|
||
|
LeafSearch:
|
||
|
for q := p; q != nil; q = q.Link {
|
||
|
switch q.As {
|
||
|
case obj.ACALL:
|
||
|
// Treat common runtime calls that take no arguments
|
||
|
// the same as duffcopy and duffzero.
|
||
|
if !isZeroArgRuntimeCall(q.To.Sym) {
|
||
|
leaf = false
|
||
|
break LeafSearch
|
||
|
}
|
||
|
fallthrough
|
||
|
case obj.ADUFFCOPY, obj.ADUFFZERO:
|
||
|
if autoffset >= obj.StackSmall-8 {
|
||
|
leaf = false
|
||
|
break LeafSearch
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
|
||
|
if leaf {
|
||
|
p.From3.Offset |= obj.NOSPLIT
|
||
|
}
|
||
|
}
|
||
|
|
||
|
if p.From3Offset()&obj.NOSPLIT == 0 || p.From3Offset()&obj.WRAPPER != 0 {
|
||
|
p = obj.Appendp(ctxt, p)
|
||
|
p = load_g_cx(ctxt, p) // load g into CX
|
||
|
}
|
||
|
|
||
|
if cursym.Text.From3Offset()&obj.NOSPLIT == 0 {
|
||
|
p = stacksplit(ctxt, p, autoffset, int32(textarg)) // emit split check
|
||
|
}
|
||
|
|
||
|
if autoffset != 0 {
|
||
|
if autoffset%int32(ctxt.Arch.RegSize) != 0 {
|
||
|
ctxt.Diag("unaligned stack size %d", autoffset)
|
||
|
}
|
||
|
p = obj.Appendp(ctxt, p)
|
||
|
p.As = AADJSP
|
||
|
p.From.Type = obj.TYPE_CONST
|
||
|
p.From.Offset = int64(autoffset)
|
||
|
p.Spadj = autoffset
|
||
|
}
|
||
|
|
||
|
deltasp := autoffset
|
||
|
|
||
|
if bpsize > 0 {
|
||
|
// Save caller's BP
|
||
|
p = obj.Appendp(ctxt, p)
|
||
|
|
||
|
p.As = AMOVQ
|
||
|
p.From.Type = obj.TYPE_REG
|
||
|
p.From.Reg = REG_BP
|
||
|
p.To.Type = obj.TYPE_MEM
|
||
|
p.To.Reg = REG_SP
|
||
|
p.To.Scale = 1
|
||
|
p.To.Offset = int64(autoffset) - int64(bpsize)
|
||
|
|
||
|
// Move current frame to BP
|
||
|
p = obj.Appendp(ctxt, p)
|
||
|
|
||
|
p.As = ALEAQ
|
||
|
p.From.Type = obj.TYPE_MEM
|
||
|
p.From.Reg = REG_SP
|
||
|
p.From.Scale = 1
|
||
|
p.From.Offset = int64(autoffset) - int64(bpsize)
|
||
|
p.To.Type = obj.TYPE_REG
|
||
|
p.To.Reg = REG_BP
|
||
|
}
|
||
|
|
||
|
if cursym.Text.From3Offset()&obj.WRAPPER != 0 {
|
||
|
// if(g->panic != nil && g->panic->argp == FP) g->panic->argp = bottom-of-frame
|
||
|
//
|
||
|
// MOVQ g_panic(CX), BX
|
||
|
// TESTQ BX, BX
|
||
|
// JEQ end
|
||
|
// LEAQ (autoffset+8)(SP), DI
|
||
|
// CMPQ panic_argp(BX), DI
|
||
|
// JNE end
|
||
|
// MOVQ SP, panic_argp(BX)
|
||
|
// end:
|
||
|
// NOP
|
||
|
//
|
||
|
// The NOP is needed to give the jumps somewhere to land.
|
||
|
// It is a liblink NOP, not an x86 NOP: it encodes to 0 instruction bytes.
|
||
|
|
||
|
p = obj.Appendp(ctxt, p)
|
||
|
|
||
|
p.As = AMOVQ
|
||
|
p.From.Type = obj.TYPE_MEM
|
||
|
p.From.Reg = REG_CX
|
||
|
p.From.Offset = 4 * int64(ctxt.Arch.PtrSize) // G.panic
|
||
|
p.To.Type = obj.TYPE_REG
|
||
|
p.To.Reg = REG_BX
|
||
|
if ctxt.Headtype == obj.Hnacl && p.Mode == 64 {
|
||
|
p.As = AMOVL
|
||
|
p.From.Type = obj.TYPE_MEM
|
||
|
p.From.Reg = REG_R15
|
||
|
p.From.Scale = 1
|
||
|
p.From.Index = REG_CX
|
||
|
}
|
||
|
if p.Mode == 32 {
|
||
|
p.As = AMOVL
|
||
|
}
|
||
|
|
||
|
p = obj.Appendp(ctxt, p)
|
||
|
p.As = ATESTQ
|
||
|
p.From.Type = obj.TYPE_REG
|
||
|
p.From.Reg = REG_BX
|
||
|
p.To.Type = obj.TYPE_REG
|
||
|
p.To.Reg = REG_BX
|
||
|
if ctxt.Headtype == obj.Hnacl || p.Mode == 32 {
|
||
|
p.As = ATESTL
|
||
|
}
|
||
|
|
||
|
p = obj.Appendp(ctxt, p)
|
||
|
p.As = AJEQ
|
||
|
p.To.Type = obj.TYPE_BRANCH
|
||
|
p1 := p
|
||
|
|
||
|
p = obj.Appendp(ctxt, p)
|
||
|
p.As = ALEAQ
|
||
|
p.From.Type = obj.TYPE_MEM
|
||
|
p.From.Reg = REG_SP
|
||
|
p.From.Offset = int64(autoffset) + int64(ctxt.Arch.RegSize)
|
||
|
p.To.Type = obj.TYPE_REG
|
||
|
p.To.Reg = REG_DI
|
||
|
if ctxt.Headtype == obj.Hnacl || p.Mode == 32 {
|
||
|
p.As = ALEAL
|
||
|
}
|
||
|
|
||
|
p = obj.Appendp(ctxt, p)
|
||
|
p.As = ACMPQ
|
||
|
p.From.Type = obj.TYPE_MEM
|
||
|
p.From.Reg = REG_BX
|
||
|
p.From.Offset = 0 // Panic.argp
|
||
|
p.To.Type = obj.TYPE_REG
|
||
|
p.To.Reg = REG_DI
|
||
|
if ctxt.Headtype == obj.Hnacl && p.Mode == 64 {
|
||
|
p.As = ACMPL
|
||
|
p.From.Type = obj.TYPE_MEM
|
||
|
p.From.Reg = REG_R15
|
||
|
p.From.Scale = 1
|
||
|
p.From.Index = REG_BX
|
||
|
}
|
||
|
if p.Mode == 32 {
|
||
|
p.As = ACMPL
|
||
|
}
|
||
|
|
||
|
p = obj.Appendp(ctxt, p)
|
||
|
p.As = AJNE
|
||
|
p.To.Type = obj.TYPE_BRANCH
|
||
|
p2 := p
|
||
|
|
||
|
p = obj.Appendp(ctxt, p)
|
||
|
p.As = AMOVQ
|
||
|
p.From.Type = obj.TYPE_REG
|
||
|
p.From.Reg = REG_SP
|
||
|
p.To.Type = obj.TYPE_MEM
|
||
|
p.To.Reg = REG_BX
|
||
|
p.To.Offset = 0 // Panic.argp
|
||
|
if ctxt.Headtype == obj.Hnacl && p.Mode == 64 {
|
||
|
p.As = AMOVL
|
||
|
p.To.Type = obj.TYPE_MEM
|
||
|
p.To.Reg = REG_R15
|
||
|
p.To.Scale = 1
|
||
|
p.To.Index = REG_BX
|
||
|
}
|
||
|
if p.Mode == 32 {
|
||
|
p.As = AMOVL
|
||
|
}
|
||
|
|
||
|
p = obj.Appendp(ctxt, p)
|
||
|
p.As = obj.ANOP
|
||
|
p1.Pcond = p
|
||
|
p2.Pcond = p
|
||
|
}
|
||
|
|
||
|
for ; p != nil; p = p.Link {
|
||
|
pcsize := int(p.Mode) / 8
|
||
|
switch p.From.Name {
|
||
|
case obj.NAME_AUTO:
|
||
|
p.From.Offset += int64(deltasp) - int64(bpsize)
|
||
|
case obj.NAME_PARAM:
|
||
|
p.From.Offset += int64(deltasp) + int64(pcsize)
|
||
|
}
|
||
|
if p.From3 != nil {
|
||
|
switch p.From3.Name {
|
||
|
case obj.NAME_AUTO:
|
||
|
p.From3.Offset += int64(deltasp) - int64(bpsize)
|
||
|
case obj.NAME_PARAM:
|
||
|
p.From3.Offset += int64(deltasp) + int64(pcsize)
|
||
|
}
|
||
|
}
|
||
|
switch p.To.Name {
|
||
|
case obj.NAME_AUTO:
|
||
|
p.To.Offset += int64(deltasp) - int64(bpsize)
|
||
|
case obj.NAME_PARAM:
|
||
|
p.To.Offset += int64(deltasp) + int64(pcsize)
|
||
|
}
|
||
|
|
||
|
switch p.As {
|
||
|
default:
|
||
|
continue
|
||
|
|
||
|
case APUSHL, APUSHFL:
|
||
|
deltasp += 4
|
||
|
p.Spadj = 4
|
||
|
continue
|
||
|
|
||
|
case APUSHQ, APUSHFQ:
|
||
|
deltasp += 8
|
||
|
p.Spadj = 8
|
||
|
continue
|
||
|
|
||
|
case APUSHW, APUSHFW:
|
||
|
deltasp += 2
|
||
|
p.Spadj = 2
|
||
|
continue
|
||
|
|
||
|
case APOPL, APOPFL:
|
||
|
deltasp -= 4
|
||
|
p.Spadj = -4
|
||
|
continue
|
||
|
|
||
|
case APOPQ, APOPFQ:
|
||
|
deltasp -= 8
|
||
|
p.Spadj = -8
|
||
|
continue
|
||
|
|
||
|
case APOPW, APOPFW:
|
||
|
deltasp -= 2
|
||
|
p.Spadj = -2
|
||
|
continue
|
||
|
|
||
|
case obj.ARET:
|
||
|
// do nothing
|
||
|
}
|
||
|
|
||
|
if autoffset != deltasp {
|
||
|
ctxt.Diag("unbalanced PUSH/POP")
|
||
|
}
|
||
|
|
||
|
if autoffset != 0 {
|
||
|
if bpsize > 0 {
|
||
|
// Restore caller's BP
|
||
|
p.As = AMOVQ
|
||
|
|
||
|
p.From.Type = obj.TYPE_MEM
|
||
|
p.From.Reg = REG_SP
|
||
|
p.From.Scale = 1
|
||
|
p.From.Offset = int64(autoffset) - int64(bpsize)
|
||
|
p.To.Type = obj.TYPE_REG
|
||
|
p.To.Reg = REG_BP
|
||
|
p = obj.Appendp(ctxt, p)
|
||
|
}
|
||
|
|
||
|
p.As = AADJSP
|
||
|
p.From.Type = obj.TYPE_CONST
|
||
|
p.From.Offset = int64(-autoffset)
|
||
|
p.Spadj = -autoffset
|
||
|
p = obj.Appendp(ctxt, p)
|
||
|
p.As = obj.ARET
|
||
|
|
||
|
// If there are instructions following
|
||
|
// this ARET, they come from a branch
|
||
|
// with the same stackframe, so undo
|
||
|
// the cleanup.
|
||
|
p.Spadj = +autoffset
|
||
|
}
|
||
|
|
||
|
if p.To.Sym != nil { // retjmp
|
||
|
p.As = obj.AJMP
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
|
||
|
func isZeroArgRuntimeCall(s *obj.LSym) bool {
|
||
|
if s == nil {
|
||
|
return false
|
||
|
}
|
||
|
switch s.Name {
|
||
|
case "runtime.panicindex", "runtime.panicslice", "runtime.panicdivide":
|
||
|
return true
|
||
|
}
|
||
|
return false
|
||
|
}
|
||
|
|
||
|
func indir_cx(ctxt *obj.Link, p *obj.Prog, a *obj.Addr) {
|
||
|
if ctxt.Headtype == obj.Hnacl && p.Mode == 64 {
|
||
|
a.Type = obj.TYPE_MEM
|
||
|
a.Reg = REG_R15
|
||
|
a.Index = REG_CX
|
||
|
a.Scale = 1
|
||
|
return
|
||
|
}
|
||
|
|
||
|
a.Type = obj.TYPE_MEM
|
||
|
a.Reg = REG_CX
|
||
|
}
|
||
|
|
||
|
// Append code to p to load g into cx.
|
||
|
// Overwrites p with the first instruction (no first appendp).
|
||
|
// Overwriting p is unusual but it lets use this in both the
|
||
|
// prologue (caller must call appendp first) and in the epilogue.
|
||
|
// Returns last new instruction.
|
||
|
func load_g_cx(ctxt *obj.Link, p *obj.Prog) *obj.Prog {
|
||
|
p.As = AMOVQ
|
||
|
if ctxt.Arch.PtrSize == 4 {
|
||
|
p.As = AMOVL
|
||
|
}
|
||
|
p.From.Type = obj.TYPE_MEM
|
||
|
p.From.Reg = REG_TLS
|
||
|
p.From.Offset = 0
|
||
|
p.To.Type = obj.TYPE_REG
|
||
|
p.To.Reg = REG_CX
|
||
|
|
||
|
next := p.Link
|
||
|
progedit(ctxt, p)
|
||
|
for p.Link != next {
|
||
|
p = p.Link
|
||
|
}
|
||
|
|
||
|
if p.From.Index == REG_TLS {
|
||
|
p.From.Scale = 2
|
||
|
}
|
||
|
|
||
|
return p
|
||
|
}
|
||
|
|
||
|
// Append code to p to check for stack split.
|
||
|
// Appends to (does not overwrite) p.
|
||
|
// Assumes g is in CX.
|
||
|
// Returns last new instruction.
|
||
|
func stacksplit(ctxt *obj.Link, p *obj.Prog, framesize int32, textarg int32) *obj.Prog {
|
||
|
cmp := ACMPQ
|
||
|
lea := ALEAQ
|
||
|
mov := AMOVQ
|
||
|
sub := ASUBQ
|
||
|
|
||
|
if ctxt.Headtype == obj.Hnacl || p.Mode == 32 {
|
||
|
cmp = ACMPL
|
||
|
lea = ALEAL
|
||
|
mov = AMOVL
|
||
|
sub = ASUBL
|
||
|
}
|
||
|
|
||
|
var q1 *obj.Prog
|
||
|
if framesize <= obj.StackSmall {
|
||
|
// small stack: SP <= stackguard
|
||
|
// CMPQ SP, stackguard
|
||
|
p = obj.Appendp(ctxt, p)
|
||
|
|
||
|
p.As = cmp
|
||
|
p.From.Type = obj.TYPE_REG
|
||
|
p.From.Reg = REG_SP
|
||
|
indir_cx(ctxt, p, &p.To)
|
||
|
p.To.Offset = 2 * int64(ctxt.Arch.PtrSize) // G.stackguard0
|
||
|
if ctxt.Cursym.CFunc() {
|
||
|
p.To.Offset = 3 * int64(ctxt.Arch.PtrSize) // G.stackguard1
|
||
|
}
|
||
|
} else if framesize <= obj.StackBig {
|
||
|
// large stack: SP-framesize <= stackguard-StackSmall
|
||
|
// LEAQ -xxx(SP), AX
|
||
|
// CMPQ AX, stackguard
|
||
|
p = obj.Appendp(ctxt, p)
|
||
|
|
||
|
p.As = lea
|
||
|
p.From.Type = obj.TYPE_MEM
|
||
|
p.From.Reg = REG_SP
|
||
|
p.From.Offset = -(int64(framesize) - obj.StackSmall)
|
||
|
p.To.Type = obj.TYPE_REG
|
||
|
p.To.Reg = REG_AX
|
||
|
|
||
|
p = obj.Appendp(ctxt, p)
|
||
|
p.As = cmp
|
||
|
p.From.Type = obj.TYPE_REG
|
||
|
p.From.Reg = REG_AX
|
||
|
indir_cx(ctxt, p, &p.To)
|
||
|
p.To.Offset = 2 * int64(ctxt.Arch.PtrSize) // G.stackguard0
|
||
|
if ctxt.Cursym.CFunc() {
|
||
|
p.To.Offset = 3 * int64(ctxt.Arch.PtrSize) // G.stackguard1
|
||
|
}
|
||
|
} else {
|
||
|
// Such a large stack we need to protect against wraparound.
|
||
|
// If SP is close to zero:
|
||
|
// SP-stackguard+StackGuard <= framesize + (StackGuard-StackSmall)
|
||
|
// The +StackGuard on both sides is required to keep the left side positive:
|
||
|
// SP is allowed to be slightly below stackguard. See stack.h.
|
||
|
//
|
||
|
// Preemption sets stackguard to StackPreempt, a very large value.
|
||
|
// That breaks the math above, so we have to check for that explicitly.
|
||
|
// MOVQ stackguard, CX
|
||
|
// CMPQ CX, $StackPreempt
|
||
|
// JEQ label-of-call-to-morestack
|
||
|
// LEAQ StackGuard(SP), AX
|
||
|
// SUBQ CX, AX
|
||
|
// CMPQ AX, $(framesize+(StackGuard-StackSmall))
|
||
|
|
||
|
p = obj.Appendp(ctxt, p)
|
||
|
|
||
|
p.As = mov
|
||
|
indir_cx(ctxt, p, &p.From)
|
||
|
p.From.Offset = 2 * int64(ctxt.Arch.PtrSize) // G.stackguard0
|
||
|
if ctxt.Cursym.CFunc() {
|
||
|
p.From.Offset = 3 * int64(ctxt.Arch.PtrSize) // G.stackguard1
|
||
|
}
|
||
|
p.To.Type = obj.TYPE_REG
|
||
|
p.To.Reg = REG_SI
|
||
|
|
||
|
p = obj.Appendp(ctxt, p)
|
||
|
p.As = cmp
|
||
|
p.From.Type = obj.TYPE_REG
|
||
|
p.From.Reg = REG_SI
|
||
|
p.To.Type = obj.TYPE_CONST
|
||
|
p.To.Offset = obj.StackPreempt
|
||
|
if p.Mode == 32 {
|
||
|
p.To.Offset = int64(uint32(obj.StackPreempt & (1<<32 - 1)))
|
||
|
}
|
||
|
|
||
|
p = obj.Appendp(ctxt, p)
|
||
|
p.As = AJEQ
|
||
|
p.To.Type = obj.TYPE_BRANCH
|
||
|
q1 = p
|
||
|
|
||
|
p = obj.Appendp(ctxt, p)
|
||
|
p.As = lea
|
||
|
p.From.Type = obj.TYPE_MEM
|
||
|
p.From.Reg = REG_SP
|
||
|
p.From.Offset = obj.StackGuard
|
||
|
p.To.Type = obj.TYPE_REG
|
||
|
p.To.Reg = REG_AX
|
||
|
|
||
|
p = obj.Appendp(ctxt, p)
|
||
|
p.As = sub
|
||
|
p.From.Type = obj.TYPE_REG
|
||
|
p.From.Reg = REG_SI
|
||
|
p.To.Type = obj.TYPE_REG
|
||
|
p.To.Reg = REG_AX
|
||
|
|
||
|
p = obj.Appendp(ctxt, p)
|
||
|
p.As = cmp
|
||
|
p.From.Type = obj.TYPE_REG
|
||
|
p.From.Reg = REG_AX
|
||
|
p.To.Type = obj.TYPE_CONST
|
||
|
p.To.Offset = int64(framesize) + (obj.StackGuard - obj.StackSmall)
|
||
|
}
|
||
|
|
||
|
// common
|
||
|
jls := obj.Appendp(ctxt, p)
|
||
|
jls.As = AJLS
|
||
|
jls.To.Type = obj.TYPE_BRANCH
|
||
|
|
||
|
var last *obj.Prog
|
||
|
for last = ctxt.Cursym.Text; last.Link != nil; last = last.Link {
|
||
|
}
|
||
|
|
||
|
// Now we are at the end of the function, but logically
|
||
|
// we are still in function prologue. We need to fix the
|
||
|
// SP data and PCDATA.
|
||
|
spfix := obj.Appendp(ctxt, last)
|
||
|
spfix.As = obj.ANOP
|
||
|
spfix.Spadj = -framesize
|
||
|
|
||
|
pcdata := obj.Appendp(ctxt, spfix)
|
||
|
pcdata.Lineno = ctxt.Cursym.Text.Lineno
|
||
|
pcdata.Mode = ctxt.Cursym.Text.Mode
|
||
|
pcdata.As = obj.APCDATA
|
||
|
pcdata.From.Type = obj.TYPE_CONST
|
||
|
pcdata.From.Offset = obj.PCDATA_StackMapIndex
|
||
|
pcdata.To.Type = obj.TYPE_CONST
|
||
|
pcdata.To.Offset = -1 // pcdata starts at -1 at function entry
|
||
|
|
||
|
call := obj.Appendp(ctxt, pcdata)
|
||
|
call.Lineno = ctxt.Cursym.Text.Lineno
|
||
|
call.Mode = ctxt.Cursym.Text.Mode
|
||
|
call.As = obj.ACALL
|
||
|
call.To.Type = obj.TYPE_BRANCH
|
||
|
call.To.Name = obj.NAME_EXTERN
|
||
|
morestack := "runtime.morestack"
|
||
|
switch {
|
||
|
case ctxt.Cursym.CFunc():
|
||
|
morestack = "runtime.morestackc"
|
||
|
case ctxt.Cursym.Text.From3Offset()&obj.NEEDCTXT == 0:
|
||
|
morestack = "runtime.morestack_noctxt"
|
||
|
}
|
||
|
call.To.Sym = obj.Linklookup(ctxt, morestack, 0)
|
||
|
// When compiling 386 code for dynamic linking, the call needs to be adjusted
|
||
|
// to follow PIC rules. This in turn can insert more instructions, so we need
|
||
|
// to keep track of the start of the call (where the jump will be to) and the
|
||
|
// end (which following instructions are appended to).
|
||
|
callend := call
|
||
|
progedit(ctxt, callend)
|
||
|
for ; callend.Link != nil; callend = callend.Link {
|
||
|
progedit(ctxt, callend.Link)
|
||
|
}
|
||
|
|
||
|
jmp := obj.Appendp(ctxt, callend)
|
||
|
jmp.As = obj.AJMP
|
||
|
jmp.To.Type = obj.TYPE_BRANCH
|
||
|
jmp.Pcond = ctxt.Cursym.Text.Link
|
||
|
jmp.Spadj = +framesize
|
||
|
|
||
|
jls.Pcond = call
|
||
|
if q1 != nil {
|
||
|
q1.Pcond = call
|
||
|
}
|
||
|
|
||
|
return jls
|
||
|
}
|
||
|
|
||
|
func follow(ctxt *obj.Link, s *obj.LSym) {
|
||
|
ctxt.Cursym = s
|
||
|
|
||
|
firstp := ctxt.NewProg()
|
||
|
lastp := firstp
|
||
|
xfol(ctxt, s.Text, &lastp)
|
||
|
lastp.Link = nil
|
||
|
s.Text = firstp.Link
|
||
|
}
|
||
|
|
||
|
func nofollow(a obj.As) bool {
|
||
|
switch a {
|
||
|
case obj.AJMP,
|
||
|
obj.ARET,
|
||
|
AIRETL,
|
||
|
AIRETQ,
|
||
|
AIRETW,
|
||
|
ARETFL,
|
||
|
ARETFQ,
|
||
|
ARETFW,
|
||
|
obj.AUNDEF:
|
||
|
return true
|
||
|
}
|
||
|
|
||
|
return false
|
||
|
}
|
||
|
|
||
|
func pushpop(a obj.As) bool {
|
||
|
switch a {
|
||
|
case APUSHL,
|
||
|
APUSHFL,
|
||
|
APUSHQ,
|
||
|
APUSHFQ,
|
||
|
APUSHW,
|
||
|
APUSHFW,
|
||
|
APOPL,
|
||
|
APOPFL,
|
||
|
APOPQ,
|
||
|
APOPFQ,
|
||
|
APOPW,
|
||
|
APOPFW:
|
||
|
return true
|
||
|
}
|
||
|
|
||
|
return false
|
||
|
}
|
||
|
|
||
|
func relinv(a obj.As) obj.As {
|
||
|
switch a {
|
||
|
case AJEQ:
|
||
|
return AJNE
|
||
|
case AJNE:
|
||
|
return AJEQ
|
||
|
case AJLE:
|
||
|
return AJGT
|
||
|
case AJLS:
|
||
|
return AJHI
|
||
|
case AJLT:
|
||
|
return AJGE
|
||
|
case AJMI:
|
||
|
return AJPL
|
||
|
case AJGE:
|
||
|
return AJLT
|
||
|
case AJPL:
|
||
|
return AJMI
|
||
|
case AJGT:
|
||
|
return AJLE
|
||
|
case AJHI:
|
||
|
return AJLS
|
||
|
case AJCS:
|
||
|
return AJCC
|
||
|
case AJCC:
|
||
|
return AJCS
|
||
|
case AJPS:
|
||
|
return AJPC
|
||
|
case AJPC:
|
||
|
return AJPS
|
||
|
case AJOS:
|
||
|
return AJOC
|
||
|
case AJOC:
|
||
|
return AJOS
|
||
|
}
|
||
|
|
||
|
log.Fatalf("unknown relation: %s", a)
|
||
|
return 0
|
||
|
}
|
||
|
|
||
|
func xfol(ctxt *obj.Link, p *obj.Prog, last **obj.Prog) {
|
||
|
var q *obj.Prog
|
||
|
var i int
|
||
|
var a obj.As
|
||
|
|
||
|
loop:
|
||
|
if p == nil {
|
||
|
return
|
||
|
}
|
||
|
if p.As == obj.AJMP {
|
||
|
q = p.Pcond
|
||
|
if q != nil && q.As != obj.ATEXT {
|
||
|
/* mark instruction as done and continue layout at target of jump */
|
||
|
p.Mark |= DONE
|
||
|
|
||
|
p = q
|
||
|
if p.Mark&DONE == 0 {
|
||
|
goto loop
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
|
||
|
if p.Mark&DONE != 0 {
|
||
|
/*
|
||
|
* p goes here, but already used it elsewhere.
|
||
|
* copy up to 4 instructions or else branch to other copy.
|
||
|
*/
|
||
|
i = 0
|
||
|
q = p
|
||
|
for ; i < 4; i, q = i+1, q.Link {
|
||
|
if q == nil {
|
||
|
break
|
||
|
}
|
||
|
if q == *last {
|
||
|
break
|
||
|
}
|
||
|
a = q.As
|
||
|
if a == obj.ANOP {
|
||
|
i--
|
||
|
continue
|
||
|
}
|
||
|
|
||
|
if nofollow(a) || pushpop(a) {
|
||
|
break // NOTE(rsc): arm does goto copy
|
||
|
}
|
||
|
if q.Pcond == nil || q.Pcond.Mark&DONE != 0 {
|
||
|
continue
|
||
|
}
|
||
|
if a == obj.ACALL || a == ALOOP {
|
||
|
continue
|
||
|
}
|
||
|
for {
|
||
|
if p.As == obj.ANOP {
|
||
|
p = p.Link
|
||
|
continue
|
||
|
}
|
||
|
|
||
|
q = obj.Copyp(ctxt, p)
|
||
|
p = p.Link
|
||
|
q.Mark |= DONE
|
||
|
(*last).Link = q
|
||
|
*last = q
|
||
|
if q.As != a || q.Pcond == nil || q.Pcond.Mark&DONE != 0 {
|
||
|
continue
|
||
|
}
|
||
|
|
||
|
q.As = relinv(q.As)
|
||
|
p = q.Pcond
|
||
|
q.Pcond = q.Link
|
||
|
q.Link = p
|
||
|
xfol(ctxt, q.Link, last)
|
||
|
p = q.Link
|
||
|
if p.Mark&DONE != 0 {
|
||
|
return
|
||
|
}
|
||
|
goto loop
|
||
|
/* */
|
||
|
}
|
||
|
}
|
||
|
q = ctxt.NewProg()
|
||
|
q.As = obj.AJMP
|
||
|
q.Lineno = p.Lineno
|
||
|
q.To.Type = obj.TYPE_BRANCH
|
||
|
q.To.Offset = p.Pc
|
||
|
q.Pcond = p
|
||
|
p = q
|
||
|
}
|
||
|
|
||
|
/* emit p */
|
||
|
p.Mark |= DONE
|
||
|
|
||
|
(*last).Link = p
|
||
|
*last = p
|
||
|
a = p.As
|
||
|
|
||
|
/* continue loop with what comes after p */
|
||
|
if nofollow(a) {
|
||
|
return
|
||
|
}
|
||
|
if p.Pcond != nil && a != obj.ACALL {
|
||
|
/*
|
||
|
* some kind of conditional branch.
|
||
|
* recurse to follow one path.
|
||
|
* continue loop on the other.
|
||
|
*/
|
||
|
q = obj.Brchain(ctxt, p.Pcond)
|
||
|
if q != nil {
|
||
|
p.Pcond = q
|
||
|
}
|
||
|
q = obj.Brchain(ctxt, p.Link)
|
||
|
if q != nil {
|
||
|
p.Link = q
|
||
|
}
|
||
|
if p.From.Type == obj.TYPE_CONST {
|
||
|
if p.From.Offset == 1 {
|
||
|
/*
|
||
|
* expect conditional jump to be taken.
|
||
|
* rewrite so that's the fall-through case.
|
||
|
*/
|
||
|
p.As = relinv(a)
|
||
|
|
||
|
q = p.Link
|
||
|
p.Link = p.Pcond
|
||
|
p.Pcond = q
|
||
|
}
|
||
|
} else {
|
||
|
q = p.Link
|
||
|
if q.Mark&DONE != 0 {
|
||
|
if a != ALOOP {
|
||
|
p.As = relinv(a)
|
||
|
p.Link = p.Pcond
|
||
|
p.Pcond = q
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
|
||
|
xfol(ctxt, p.Link, last)
|
||
|
if p.Pcond.Mark&DONE != 0 {
|
||
|
return
|
||
|
}
|
||
|
p = p.Pcond
|
||
|
goto loop
|
||
|
}
|
||
|
|
||
|
p = p.Link
|
||
|
goto loop
|
||
|
}
|
||
|
|
||
|
var unaryDst = map[obj.As]bool{
|
||
|
ABSWAPL: true,
|
||
|
ABSWAPQ: true,
|
||
|
ACMPXCHG8B: true,
|
||
|
ADECB: true,
|
||
|
ADECL: true,
|
||
|
ADECQ: true,
|
||
|
ADECW: true,
|
||
|
AINCB: true,
|
||
|
AINCL: true,
|
||
|
AINCQ: true,
|
||
|
AINCW: true,
|
||
|
ANEGB: true,
|
||
|
ANEGL: true,
|
||
|
ANEGQ: true,
|
||
|
ANEGW: true,
|
||
|
ANOTB: true,
|
||
|
ANOTL: true,
|
||
|
ANOTQ: true,
|
||
|
ANOTW: true,
|
||
|
APOPL: true,
|
||
|
APOPQ: true,
|
||
|
APOPW: true,
|
||
|
ASETCC: true,
|
||
|
ASETCS: true,
|
||
|
ASETEQ: true,
|
||
|
ASETGE: true,
|
||
|
ASETGT: true,
|
||
|
ASETHI: true,
|
||
|
ASETLE: true,
|
||
|
ASETLS: true,
|
||
|
ASETLT: true,
|
||
|
ASETMI: true,
|
||
|
ASETNE: true,
|
||
|
ASETOC: true,
|
||
|
ASETOS: true,
|
||
|
ASETPC: true,
|
||
|
ASETPL: true,
|
||
|
ASETPS: true,
|
||
|
AFFREE: true,
|
||
|
AFLDENV: true,
|
||
|
AFSAVE: true,
|
||
|
AFSTCW: true,
|
||
|
AFSTENV: true,
|
||
|
AFSTSW: true,
|
||
|
AFXSAVE: true,
|
||
|
AFXSAVE64: true,
|
||
|
ASTMXCSR: true,
|
||
|
}
|
||
|
|
||
|
var Linkamd64 = obj.LinkArch{
|
||
|
Arch: sys.ArchAMD64,
|
||
|
Preprocess: preprocess,
|
||
|
Assemble: span6,
|
||
|
Follow: follow,
|
||
|
Progedit: progedit,
|
||
|
UnaryDst: unaryDst,
|
||
|
}
|
||
|
|
||
|
var Linkamd64p32 = obj.LinkArch{
|
||
|
Arch: sys.ArchAMD64P32,
|
||
|
Preprocess: preprocess,
|
||
|
Assemble: span6,
|
||
|
Follow: follow,
|
||
|
Progedit: progedit,
|
||
|
UnaryDst: unaryDst,
|
||
|
}
|
||
|
|
||
|
var Link386 = obj.LinkArch{
|
||
|
Arch: sys.Arch386,
|
||
|
Preprocess: preprocess,
|
||
|
Assemble: span6,
|
||
|
Follow: follow,
|
||
|
Progedit: progedit,
|
||
|
UnaryDst: unaryDst,
|
||
|
}
|