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Fix for unix stack scanner now that gcc sometimes omits frame pointers.

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 Change: 178810
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This commit is contained in:
David Lovemore 2012-08-01 20:45:29 +01:00
parent edef673fc0
commit 025e16f239
1 changed files with 10 additions and 5 deletions
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15
mps/code/ssixi3.c
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@ -22,6 +22,8 @@
*
* .source.callees.saves: Set of callee-saved registers taken from
* CALL_USED_REGISTERS in <gcc-sources>/config/i386/i386.h.
* ebp added to the list because gcc now doesn't always use it as
* a frame pointer so it could contain a root.
*
* ASSUMPTIONS
*
@ -49,20 +51,23 @@ SRCID(ssixi3, "$Id$");
Res StackScan(ScanState ss, Addr *stackBot)
{
Addr calleeSaveRegs[4];
Addr *stackTop;
Res res;
/* .assume.asm.stack */
ASMV("push %ebx"); /* These registers are callee-saved */
ASMV("push %esi"); /* and so may contain roots. They are pushed */
ASMV("push %edi"); /* for scanning. See .source.callees.saves. */
/* Store the callee save registers on the stack so they get scanned
* as they may contain roots.
*/
ASMV("mov %%ebx, %0" : "=m" (calleeSaveRegs[0]));
ASMV("mov %%esi, %0" : "=m" (calleeSaveRegs[1]));
ASMV("mov %%edi, %0" : "=m" (calleeSaveRegs[2]));
ASMV("mov %%ebp, %0" : "=m" (calleeSaveRegs[3]));
ASMV("mov %%esp, %0" : "=r" (stackTop) :); /* stackTop = esp */
AVER(AddrIsAligned((Addr)stackTop, sizeof(Addr))); /* .assume.align */
res = TraceScanArea(ss, stackTop, stackBot);
ASMV("add $12, %esp"); /* pop 3 regs to restore the stack pointer */
return res;
}