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cmd/6l, cmd/8l: add -Z flag to zero stack frame on entry

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Replacement for GOEXPERIMENT=zerostack, easier to use.
Does not require a separate toolchain.

R=ken2
CC=golang-dev
https://golang.org/cl/6996051
This commit is contained in:
Russ Cox 2012-12-22 11:20:17 -05:00
parent e431398e09
commit b9da27bed2
2 changed files with 56 additions and 0 deletions
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28
src/cmd/6l/pass.c
View file

@ -653,6 +653,34 @@ dostkoff(void)
q1->pcond = p;
}
if(debug['Z'] && autoffset && !(cursym->text->from.scale&NOSPLIT)) {
// 6l -Z means zero the stack frame on entry.
// This slows down function calls but can help avoid
// false positives in garbage collection.
p = appendp(p);
p->as = AMOVQ;
p->from.type = D_SP;
p->to.type = D_DI;
p = appendp(p);
p->as = AMOVQ;
p->from.type = D_CONST;
p->from.offset = autoffset/8;
p->to.type = D_CX;
p = appendp(p);
p->as = AMOVQ;
p->from.type = D_CONST;
p->from.offset = 0;
p->to.type = D_AX;
p = appendp(p);
p->as = AREP;
p = appendp(p);
p->as = ASTOSQ;
}
for(; p != P; p = p->link) {
pcsize = p->mode/8;
a = p->from.type;

28
src/cmd/8l/pass.c
View file

@ -593,6 +593,34 @@ dostkoff(void)
}
deltasp = autoffset;
if(debug['Z'] && autoffset && !(cursym->text->from.scale&NOSPLIT)) {
// 8l -Z means zero the stack frame on entry.
// This slows down function calls but can help avoid
// false positives in garbage collection.
p = appendp(p);
p->as = AMOVL;
p->from.type = D_SP;
p->to.type = D_DI;
p = appendp(p);
p->as = AMOVL;
p->from.type = D_CONST;
p->from.offset = autoffset/4;
p->to.type = D_CX;
p = appendp(p);
p->as = AMOVL;
p->from.type = D_CONST;
p->from.offset = 0;
p->to.type = D_AX;
p = appendp(p);
p->as = AREP;
p = appendp(p);
p->as = ASTOSL;
}
for(; p != P; p = p->link) {
a = p->from.type;
if(a == D_AUTO)