Commit 41fd8d64 authored by Michael Munday's avatar Michael Munday

cmd/internal/obj: make morestack cutoff the same on all architectures

There is always 128 bytes available below the stackguard. Allow functions
with medium-sized stack frames to use this, potentially allowing them to
avoid growing the stack.

This change makes all architectures use the same calculation as x86.

Change-Id: I2afb1a7c686ae5a933e50903b31ea4106e4cd0a0
Reviewed-on: https://go-review.googlesource.com/38734Reviewed-by: default avatarCherry Zhang <cherryyz@google.com>
parent fbe67239
......@@ -747,14 +747,14 @@ func stacksplit(ctxt *obj.Link, p *obj.Prog, framesize int32) *obj.Prog {
p.Reg = REGSP
} else if framesize <= obj.StackBig {
// large stack: SP-framesize < stackguard-StackSmall
// MOVW $-framesize(SP), R2
// MOVW $-(framesize-StackSmall)(SP), R2
// CMP stackguard, R2
p = obj.Appendp(ctxt, p)
p.As = AMOVW
p.From.Type = obj.TYPE_ADDR
p.From.Reg = REGSP
p.From.Offset = int64(-framesize)
p.From.Offset = -(int64(framesize) - obj.StackSmall)
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_R2
......
......@@ -82,13 +82,13 @@ func stacksplit(ctxt *obj.Link, p *obj.Prog, framesize int32) *obj.Prog {
p.Reg = REG_R2
} else if framesize <= obj.StackBig {
// large stack: SP-framesize < stackguard-StackSmall
// SUB $framesize, SP, R2
// SUB $(framesize-StackSmall), SP, R2
// CMP stackguard, R2
p = obj.Appendp(ctxt, p)
p.As = ASUB
p.From.Type = obj.TYPE_CONST
p.From.Offset = int64(framesize)
p.From.Offset = int64(framesize) - obj.StackSmall
p.Reg = REGSP
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_R2
......
......@@ -658,13 +658,13 @@ func stacksplit(ctxt *obj.Link, p *obj.Prog, framesize int32) *obj.Prog {
p.To.Reg = REG_R1
} else if framesize <= obj.StackBig {
// large stack: SP-framesize < stackguard-StackSmall
// ADD $-framesize, SP, R2
// ADD $-(framesize-StackSmall), SP, R2
// SGTU R2, stackguard, R1
p = obj.Appendp(ctxt, p)
p.As = add
p.From.Type = obj.TYPE_CONST
p.From.Offset = int64(-framesize)
p.From.Offset = -(int64(framesize) - obj.StackSmall)
p.Reg = REGSP
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_R2
......
......@@ -868,13 +868,13 @@ func stacksplit(ctxt *obj.Link, p *obj.Prog, framesize int32) *obj.Prog {
p.To.Reg = REGSP
} else if framesize <= obj.StackBig {
// large stack: SP-framesize < stackguard-StackSmall
// ADD $-framesize, SP, R4
// ADD $-(framesize-StackSmall), SP, R4
// CMP stackguard, R4
p = obj.Appendp(ctxt, p)
p.As = AADD
p.From.Type = obj.TYPE_CONST
p.From.Offset = int64(-framesize)
p.From.Offset = -(int64(framesize) - obj.StackSmall)
p.Reg = REGSP
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_R4
......
......@@ -586,13 +586,13 @@ func stacksplitPre(ctxt *obj.Link, p *obj.Prog, framesize int32) (*obj.Prog, *ob
} else if framesize <= obj.StackBig {
// large stack: SP-framesize < stackguard-StackSmall
// ADD $-framesize, SP, R4
// ADD $-(framesize-StackSmall), SP, R4
// CMP stackguard, R4
p = obj.Appendp(ctxt, p)
p.As = AADD
p.From.Type = obj.TYPE_CONST
p.From.Offset = int64(-framesize)
p.From.Offset = -(int64(framesize) - obj.StackSmall)
p.Reg = REGSP
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_R4
......
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