[lldb-dev] [Bug 38076] New: lldb and gdb compute different values for expressions

[via lldb-dev]

https://bugs.llvm.org/show_bug.cgi?id=38076

            Bug ID: 38076
           Summary: lldb and gdb compute different values for expressions
           Product: lldb
           Version: unspecified
          Hardware: PC
                OS: Linux
            Status: NEW
          Severity: enhancement
          Priority: P
         Component: All Bugs
          Assignee: lldb-dev at lists.llvm.org
          Reporter: tianxiao.gu at gmail.com
                CC: chengniansun at gmail.com, davide at freebsd.org,
                    llvm-bugs at lists.llvm.org, su at cs.ucdavis.edu

Created attachment 20530
  --> https://bugs.llvm.org/attachment.cgi?id=20530&action=edit
reproducing scripts

See attached zip file to reproduce the inconsistency.

Affected version:

lldb version 7.0.0 (http://llvm.org/svn/llvm-project/lldb/trunk revision
336302)
  clang revision 336302
  llvm revision 336302


~~~test.c
typedef unsigned int uint32_t;
struct S0 {
  signed f2;
};
static g_463 = 0x1561983AL;
void func_1(void)
{
  struct S0 l_19;
  l_19.f2 = 419;
  uint32_t l_4037 = 4294967295UL;
  l_19.f2 = g_463; // break here and evaluate ((l_4037 % (-(g_463))) | l_19.f2)
}
int main()
{
  func_1();
  return 0;
}
~~~


~~~test.sh
#! /bin/bash

BASEDIR=$(pushd $(dirname $BASH_SOURCE[0]) > /dev/null && pwd && popd >
/dev/null)

readonly TEST_NAME=${1:-test.c}
readonly EXE=test.out
readonly CC=clang
readonly MODE=-m64
readonly LINE_NUMBER=12

rm -f $EXE
$CC -w ${MODE} -g3 -o $EXE $TEST_NAME

if [[ ! -f $EXE ]]
then
    exit 1
fi


cat << EOF > lldb-cmds.txt
breakpoint set -file $TEST_NAME -line $LINE_NUMBER
process launch
print ((l_4037 % (-(g_463))) | l_19.f2)
EOF

cat << EOF > gdb-cmds.txt
break $TEST_NAME:$LINE_NUMBER
run
print ((l_4037 % (-(g_463))) | l_19.f2)
EOF


LLDB_OUTPUT=$(lldb -s lldb-cmds.txt --batch $EXE | grep "\$0" | awk -e '{print
$5}')

if [[ $? != 0 ]]
then
    exit 1
fi

if [[ $LLDB_OUTPUT == "" ]]
then
    exit 1
fi

GDB_OUTPUT=$(gdb -x gdb-cmds.txt --batch $EXE | grep "\$1" | awk -e '{print
$3}')

if [[ $? != 0 ]]
then
    exit 1
fi

if [[ $GDB_OUTPUT == "" ]]
then
    exit 1
fi

echo "LLDB_OUTPUT: $LLDB_OUTPUT, GDB_OUTPUT=$GDB_OUTPUT"

if [[ $LLDB_OUTPUT != $GDB_OUTPUT ]]
then
    exit 0
else
    exit 1
fi
~~~

Output:

LLDB_OUTPUT: 4294967295, GDB_OUTPUT=358717499

-- 
You are receiving this mail because:
You are the assignee for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/lldb-dev/attachments/20180706/c28e5c9d/attachment.html>