Initial commit: Go 1.23 release state

src/cmd/compile/internal/amd64/ggen.go

@@ -0,0 +1,135 @@
+// Copyright 2009 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 amd64
+
+import (
+	"cmd/compile/internal/ir"
+	"cmd/compile/internal/objw"
+	"cmd/compile/internal/types"
+	"cmd/internal/obj"
+	"cmd/internal/obj/x86"
+	"internal/buildcfg"
+)
+
+// no floating point in note handlers on Plan 9
+var isPlan9 = buildcfg.GOOS == "plan9"
+
+// DUFFZERO consists of repeated blocks of 4 MOVUPSs + LEAQ,
+// See runtime/mkduff.go.
+const (
+	dzBlocks    = 16 // number of MOV/ADD blocks
+	dzBlockLen  = 4  // number of clears per block
+	dzBlockSize = 23 // size of instructions in a single block
+	dzMovSize   = 5  // size of single MOV instruction w/ offset
+	dzLeaqSize  = 4  // size of single LEAQ instruction
+	dzClearStep = 16 // number of bytes cleared by each MOV instruction
+
+	dzClearLen = dzClearStep * dzBlockLen // bytes cleared by one block
+	dzSize     = dzBlocks * dzBlockSize
+)
+
+// dzOff returns the offset for a jump into DUFFZERO.
+// b is the number of bytes to zero.
+func dzOff(b int64) int64 {
+	off := int64(dzSize)
+	off -= b / dzClearLen * dzBlockSize
+	tailLen := b % dzClearLen
+	if tailLen >= dzClearStep {
+		off -= dzLeaqSize + dzMovSize*(tailLen/dzClearStep)
+	}
+	return off
+}
+
+// duffzeroDI returns the pre-adjustment to DI for a call to DUFFZERO.
+// b is the number of bytes to zero.
+func dzDI(b int64) int64 {
+	tailLen := b % dzClearLen
+	if tailLen < dzClearStep {
+		return 0
+	}
+	tailSteps := tailLen / dzClearStep
+	return -dzClearStep * (dzBlockLen - tailSteps)
+}
+
+func zerorange(pp *objw.Progs, p *obj.Prog, off, cnt int64, state *uint32) *obj.Prog {
+	const (
+		r13 = 1 << iota // if R13 is already zeroed.
+	)
+
+	if cnt == 0 {
+		return p
+	}
+
+	if cnt == 8 {
+		p = pp.Append(p, x86.AMOVQ, obj.TYPE_REG, x86.REG_X15, 0, obj.TYPE_MEM, x86.REG_SP, off)
+	} else if !isPlan9 && cnt <= int64(8*types.RegSize) {
+		for i := int64(0); i < cnt/16; i++ {
+			p = pp.Append(p, x86.AMOVUPS, obj.TYPE_REG, x86.REG_X15, 0, obj.TYPE_MEM, x86.REG_SP, off+i*16)
+		}
+
+		if cnt%16 != 0 {
+			p = pp.Append(p, x86.AMOVUPS, obj.TYPE_REG, x86.REG_X15, 0, obj.TYPE_MEM, x86.REG_SP, off+cnt-int64(16))
+		}
+	} else if !isPlan9 && (cnt <= int64(128*types.RegSize)) {
+		// Save DI to r12. With the amd64 Go register abi, DI can contain
+		// an incoming parameter, whereas R12 is always scratch.
+		p = pp.Append(p, x86.AMOVQ, obj.TYPE_REG, x86.REG_DI, 0, obj.TYPE_REG, x86.REG_R12, 0)
+		// Emit duffzero call
+		p = pp.Append(p, leaptr, obj.TYPE_MEM, x86.REG_SP, off+dzDI(cnt), obj.TYPE_REG, x86.REG_DI, 0)
+		p = pp.Append(p, obj.ADUFFZERO, obj.TYPE_NONE, 0, 0, obj.TYPE_ADDR, 0, dzOff(cnt))
+		p.To.Sym = ir.Syms.Duffzero
+		if cnt%16 != 0 {
+			p = pp.Append(p, x86.AMOVUPS, obj.TYPE_REG, x86.REG_X15, 0, obj.TYPE_MEM, x86.REG_DI, -int64(8))
+		}
+		// Restore DI from r12
+		p = pp.Append(p, x86.AMOVQ, obj.TYPE_REG, x86.REG_R12, 0, obj.TYPE_REG, x86.REG_DI, 0)
+
+	} else {
+		// When the register ABI is in effect, at this point in the
+		// prolog we may have live values in all of RAX,RDI,RCX. Save
+		// them off to registers before the REPSTOSQ below, then
+		// restore. Note that R12 and R13 are always available as
+		// scratch regs; here we also use R15 (this is safe to do
+		// since there won't be any globals accessed in the prolog).
+		// See rewriteToUseGot() in obj6.go for more on r15 use.
+
+		// Save rax/rdi/rcx
+		p = pp.Append(p, x86.AMOVQ, obj.TYPE_REG, x86.REG_DI, 0, obj.TYPE_REG, x86.REG_R12, 0)
+		p = pp.Append(p, x86.AMOVQ, obj.TYPE_REG, x86.REG_AX, 0, obj.TYPE_REG, x86.REG_R13, 0)
+		p = pp.Append(p, x86.AMOVQ, obj.TYPE_REG, x86.REG_CX, 0, obj.TYPE_REG, x86.REG_R15, 0)
+
+		// Set up the REPSTOSQ and kick it off.
+		p = pp.Append(p, x86.AXORL, obj.TYPE_REG, x86.REG_AX, 0, obj.TYPE_REG, x86.REG_AX, 0)
+		p = pp.Append(p, x86.AMOVQ, obj.TYPE_CONST, 0, cnt/int64(types.RegSize), obj.TYPE_REG, x86.REG_CX, 0)
+		p = pp.Append(p, leaptr, obj.TYPE_MEM, x86.REG_SP, off, obj.TYPE_REG, x86.REG_DI, 0)
+		p = pp.Append(p, x86.AREP, obj.TYPE_NONE, 0, 0, obj.TYPE_NONE, 0, 0)
+		p = pp.Append(p, x86.ASTOSQ, obj.TYPE_NONE, 0, 0, obj.TYPE_NONE, 0, 0)
+
+		// Restore rax/rdi/rcx
+		p = pp.Append(p, x86.AMOVQ, obj.TYPE_REG, x86.REG_R12, 0, obj.TYPE_REG, x86.REG_DI, 0)
+		p = pp.Append(p, x86.AMOVQ, obj.TYPE_REG, x86.REG_R13, 0, obj.TYPE_REG, x86.REG_AX, 0)
+		p = pp.Append(p, x86.AMOVQ, obj.TYPE_REG, x86.REG_R15, 0, obj.TYPE_REG, x86.REG_CX, 0)
+
+		// Record the fact that r13 is no longer zero.
+		*state &= ^uint32(r13)
+	}
+
+	return p
+}
+
+func ginsnop(pp *objw.Progs) *obj.Prog {
+	// This is a hardware nop (1-byte 0x90) instruction,
+	// even though we describe it as an explicit XCHGL here.
+	// Particularly, this does not zero the high 32 bits
+	// like typical *L opcodes.
+	// (gas assembles "xchg %eax,%eax" to 0x87 0xc0, which
+	// does zero the high 32 bits.)
+	p := pp.Prog(x86.AXCHGL)
+	p.From.Type = obj.TYPE_REG
+	p.From.Reg = x86.REG_AX
+	p.To.Type = obj.TYPE_REG
+	p.To.Reg = x86.REG_AX
+	return p
+}