From 025e16f239fa7014bddfaf3c876dfa15d7018165 Mon Sep 17 00:00:00 2001 From: David Lovemore Date: Wed, 1 Aug 2012 20:45:29 +0100 Subject: [PATCH] Fix for unix stack scanner now that gcc sometimes omits frame pointers. Copied from Perforce Change: 178810 ServerID: perforce.ravenbrook.com --- mps/code/ssixi3.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/mps/code/ssixi3.c b/mps/code/ssixi3.c index 950897c8840..0d1c31c7501 100644 --- a/mps/code/ssixi3.c +++ b/mps/code/ssixi3.c @@ -22,6 +22,8 @@ * * .source.callees.saves: Set of callee-saved registers taken from * CALL_USED_REGISTERS in /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; }