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fix off by 4 bug in morestack (lr again). remove storing of r0

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now that all arguments are passed on the stack.

go/test: passes 89% (310/345)

R=rsc
APPROVED=rsc
DELTA=33  (13 added, 14 deleted, 6 changed)
OCL=36009
CL=36022
This commit is contained in:
Kai Backman 2009-10-23 10:59:31 -07:00
parent a9e03ae52a
commit 0af8e1045c
3 changed files with 19 additions and 20 deletions
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23
src/cmd/5l/noop.c
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@ -128,7 +128,7 @@ noops(void)
Bflush(&bso);
pmorestack = P;
symmorestack = lookup("runtime·morestackx", 0);
symmorestack = lookup("runtime·morestack", 0);
if(symmorestack->type == STEXT)
for(p = firstp; p != P; p = p->link) {
@ -358,9 +358,10 @@ noops(void)
// split stack check for small functions
// MOVW g_stackguard(g), R1
// CMP R1, $-autosize(SP)
// MOVW.LO $autosize, R1
// MOVW.LO $args, R2
// MOVW.W.LO R14, R3
// BL.LO runtime·morestackx(SB) // modifies LR
// MOVW.W.LO R14, R3
// BL.LO runtime·morestack(SB) // modifies LR
// MOVW.W R14,$-autosize(SP)
// TODO(kaib): add more trampolines
@ -383,12 +384,22 @@ noops(void)
p->from.offset = -autosize;
p->reg = REGSP;
// MOVW.LO $args, R2
// MOVW.LO $autosize, R1
p = appendp(p);
p->as = AMOVW;
p->scond = C_SCOND_LO;
p->from.type = D_CONST;
p->from.offset = curtext->to.offset2 & ~7;
p->from.offset = 0;
p->to.type = D_REG;
p->to.reg = 1;
// MOVW.LO $args +4, R2
// also need to store the extra 4 bytes.
p = appendp(p);
p->as = AMOVW;
p->scond = C_SCOND_LO;
p->from.type = D_CONST;
p->from.offset = (curtext->to.offset2 & ~7) + 4;
p->to.type = D_REG;
p->to.reg = 2;
@ -401,7 +412,7 @@ noops(void)
p->to.type = D_REG;
p->to.reg = 3;
// BL.LO runtime·morestackx(SB) // modifies LR
// BL.LO runtime·morestack(SB) // modifies LR
p = appendp(p);
p->as = ABL;
p->scond = C_SCOND_LO;

15
src/pkg/runtime/arm/asm.s
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@ -120,7 +120,6 @@ TEXT gogocall(SB), 7, $-4
MOVW 0(g), R2 // make sure g != nil
MOVW gobuf_sp(R0), SP // restore SP
MOVW gobuf_pc(R0), LR
MOVW gobuf_r0(R0), R0
MOVW R1, PC
/*
@ -131,6 +130,8 @@ TEXT gogocall(SB), 7, $-4
// R1 frame size
// R2 arg size
// R3 prolog's LR
// NB. we do not save R0 because the we've forced 5c to pass all arguments
// on the stack.
// using frame size $-4 means do not save LR on stack.
TEXT runtime·morestack(SB),7,$-4
// Cannot grow scheduler stack (m->g0).
@ -149,7 +150,6 @@ TEXT runtime·morestack(SB),7,$-4
MOVW SP, (m_morebuf+gobuf_sp)(m) // f's caller's SP
MOVW SP, m_morefp(m) // f's caller's SP
MOVW g, (m_morebuf+gobuf_g)(m)
MOVW R0, (m_morebuf+gobuf_r0)(m)
// Set m->morepc to f's PC.
MOVW LR, m_morepc(m)
@ -169,7 +169,6 @@ TEXT reflect·call(SB), 7, $-4
// restore when returning from f.
MOVW LR, (m_morebuf+gobuf_pc)(m) // our caller's PC
MOVW SP, (m_morebuf+gobuf_sp)(m) // our caller's SP
MOVW R0, (m_morebuf+gobuf_r0)(m)
MOVW g, (m_morebuf+gobuf_g)(m)
// Set up morestack arguments to call f on a new stack.
@ -204,16 +203,6 @@ TEXT runtime·lessstack(SB), 7, $-4
MOVW (m_sched+gobuf_sp)(m), SP
B oldstack(SB)
// Optimization to make inline stack splitting code smaller
// R0 is original first argument
// R2 is argsize
// R3 is LR for f (f's caller's PC)
// using frame size $-4 means do not save LR on stack.
TEXT runtime·morestackx(SB), 7, $-4
MOVW $0, R1 // set frame size
B runtime·morestack(SB)
// void jmpdefer(fn, sp);
// called from deferreturn.
// 1. grab stored LR for caller

1
src/pkg/runtime/runtime.h
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@ -152,7 +152,6 @@ struct Gobuf
byte* sp;
byte* pc;
G* g;
uintptr r0; // used on arm
};
struct G
{