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Message-Id: <1444658340-10065-1-git-send-email-alexinbeijing@gmail.com>
Date: Mon, 12 Oct 2015 15:58:58 +0200
From: Alex Dowad <alexinbeijing@...il.com>
To: musl@...ts.openwall.com
Subject: [PATCH 1/3] in i386 CFI script, binary ops like ADD or AND modify 2nd operand, not 1st
thanks to R. Felker for noticing this problem.
---
Fixed the issue with index registers being mistakenly identified as the destination
for a binary op (thus causing their values to be treated as if overwritten). The fix
is slightly hacky, but maintains brevity. The other option would be to write a long
regex which is able to parse all x86 addressing modes.
Also tweaked commit messages.
Any other feedback will be appreciated,
Alex Dowad
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 5dc8794..fc0d8cf 100644
--- a/tools/add-cfi.i386.awk
+++ b/tools/add-cfi.i386.awk
@@ -185,12 +185,12 @@ 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),/ {
- trashed(get_reg1())
+/(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 [^,]*$/ { trashed("eax"); trashed("edx") }
-/^i?mul %e(ax|bx|cx|dx|si|di|bp),/ { trashed(get_reg1()) }
-/^i?div/ { trashed("eax"); trashed("edx") }
+/^i?mul [^,]*$/ { 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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