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Prevent potential null pointer dereference

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This null-check resolves a potential issue detected by static analysis.

It might be the case, that crash never happens due to the way this
static function is used at the moment, and because DYNFLG_CHANGED is being
cleared in dnew->genreg->Clear() few lines before, but the crash might
still happen if initial state of flags is inconsistent or surrounding
code will be changed even a little bit.

This nullcheck makes the code more robust at no performance penalty.
This commit is contained in:
Patryk Obara 2019-11-02 14:59:27 +01:00 • committed by Patryk Obara
parent 2487242011
commit 4a01b6a00d
2 changed files with 4 additions and 2 deletions
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3
src/cpu/core_dyn_x86/risc_x64.h
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@ -439,7 +439,8 @@ static void gen_synchreg(DynReg * dnew,DynReg * dsynch) {
if ((dnew->flags ^ dsynch->flags) & DYNFLG_CHANGED) {
/* Ensure the changed value gets saved */
if (dnew->flags & DYNFLG_CHANGED) {
dnew->genreg->Save();
if (GCC_LIKELY(dnew->genreg != NULL))
dnew->genreg->Save();
} else dnew->flags|=DYNFLG_CHANGED;
}
}

3
src/cpu/core_dyn_x86/risc_x86.h
View file

@ -233,7 +233,8 @@ static void gen_synchreg(DynReg * dnew,DynReg * dsynch) {
if ((dnew->flags ^ dsynch->flags) & DYNFLG_CHANGED) {
/* Ensure the changed value gets saved */
if (dnew->flags & DYNFLG_CHANGED) {
dnew->genreg->Save();
if (GCC_LIKELY(dnew->genreg != NULL))
dnew->genreg->Save();
} else dnew->flags|=DYNFLG_CHANGED;
}
}