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Date: Mon, 12 Oct 2015 15:58:59 +0200
From: Alex Dowad <alexinbeijing@...il.com>
To: musl@...ts.openwall.com
Subject: [PATCH 2/3] fix matching errors related to i386 addressing modes in CFI generation script
the regexps previously used to identify registers clobbered by MOVs, ADDs,
and various other operations would erroneously match index registers. In other
words, the following asm:
mov $0, (%eax,%ebx,4)
...would cause EBX to be considered as overwritten, which might prevent a
debugger from displaying a variable's value in a higher stack frame.
thanks to Rich Felker for noticing this problem.
---
tools/add-cfi.i386.awk | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/tools/add-cfi.i386.awk b/tools/add-cfi.i386.awk
index fc0d8cf..bd7932f 100644
--- a/tools/add-cfi.i386.awk
+++ b/tools/add-cfi.i386.awk
@@ -184,13 +184,13 @@ function trashed(register) {
}
# this does NOT exhaustively check for all possible instructions which could
# overwrite a register value inherited from the caller (just the common ones)
-/mov.*,%e(ax|bx|cx|dx|si|di|bp)/ { trashed(get_reg2()) }
-/(add|addl|sub|subl|and|or|xor|lea|sal|sar|shl|shr).*,%e(ax|bx|cx|dx|si|di|bp)/ {
+/mov.*,%e(ax|bx|cx|dx|si|di|bp)$/ { trashed(get_reg2()) }
+/(add|addl|sub|subl|and|or|xor|lea|sal|sar|shl|shr).*,%e(ax|bx|cx|dx|si|di|bp)$/ {
trashed(get_reg2())
}
-/^i?mul [^,]*$/ { trashed("eax"); trashed("edx") }
-/^i?mul.*,%e(ax|bx|cx|dx|si|di|bp)/ { trashed(get_reg2()) }
-/^i?div/ { trashed("eax"); trashed("edx") }
+/^i?mul [^,]*$/ { trashed("eax"); trashed("edx") }
+/^i?mul.*,%e(ax|bx|cx|dx|si|di|bp)$/ { trashed(get_reg2()) }
+/^i?div/ { trashed("eax"); trashed("edx") }
/(dec|inc|not|neg|pop) %e(ax|bx|cx|dx|si|di|bp)/ { trashed(get_reg()) }
/cpuid/ { trashed("eax"); trashed("ebx"); trashed("ecx"); trashed("edx") }
--
2.0.0.GIT
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