Fix UB when accessing move result flags (#6030)

Co-authored-by: Alex <[email protected]>
rh-hideout · Jan 15, 2025 · 75d5eda · 75d5eda
1 parent ed0c9a4
commit 75d5eda
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Showing 3 changed files with 15 additions and 12 deletions.
diff --git a/include/battle_util.h b/include/battle_util.h
@@ -248,6 +248,7 @@ uq4_12_t CalcTypeEffectivenessMultiplier(u32 move, u32 moveType, u32 battlerAtk,
 uq4_12_t CalcPartyMonTypeEffectivenessMultiplier(u16 move, u16 speciesDef, u16 abilityDef);
 uq4_12_t GetTypeModifier(u32 atkType, u32 defType);
 uq4_12_t GetOverworldTypeEffectiveness(struct Pokemon *mon, u8 moveType);
+void UpdateMoveResultFlags(uq4_12_t modifier, u16 *resultFlags);
 s32 GetStealthHazardDamage(enum TypeSideHazard hazardType, u32 battler);
 s32 GetStealthHazardDamageByTypesAndHP(enum TypeSideHazard hazardType, u8 type1, u8 type2, u32 maxHp);
 bool32 CanMegaEvolve(u32 battler);

diff --git a/src/battle_ai_switch_items.c b/src/battle_ai_switch_items.c
@@ -727,6 +727,8 @@ static bool32 FindMonWithFlagsAndSuperEffective(u32 battler, u16 flags, u32 perc
     for (i = firstId; i < lastId; i++)
     {
         u16 species, monAbility;
+        uq4_12_t typeMultiplier;
+        u16 moveFlags = 0;
 
         if (!IsValidForBattle(&party[i]))
             continue;
@@ -743,8 +745,9 @@ static bool32 FindMonWithFlagsAndSuperEffective(u32 battler, u16 flags, u32 perc
 
         species = GetMonData(&party[i], MON_DATA_SPECIES_OR_EGG);
         monAbility = GetMonAbility(&party[i]);
-        CalcPartyMonTypeEffectivenessMultiplier(gLastLandedMoves[battler], species, monAbility);
-        if (gBattleStruct->moveResultFlags[BATTLE_OPPOSITE(battler)] & flags)
+        typeMultiplier = CalcPartyMonTypeEffectivenessMultiplier(gLastLandedMoves[battler], species, monAbility);
+        UpdateMoveResultFlags(typeMultiplier, &moveFlags);
+        if (moveFlags & flags)
         {
             battlerIn1 = gLastHitBy[battler];
 

diff --git a/src/battle_util.c b/src/battle_util.c
@@ -10654,27 +10654,27 @@ static inline void TryNoticeIllusionInTypeEffectiveness(u32 move, u32 moveType,
         RecordAbilityBattle(battlerDef, ABILITY_ILLUSION);
 }
 
-static void UpdateMoveResultFlags(uq4_12_t modifier, u32 battler)
+void UpdateMoveResultFlags(uq4_12_t modifier, u16 *resultFlags)
 {
     if (modifier == UQ_4_12(0.0))
     {
-        gBattleStruct->moveResultFlags[battler] |= MOVE_RESULT_DOESNT_AFFECT_FOE;
-        gBattleStruct->moveResultFlags[battler] &= ~(MOVE_RESULT_NOT_VERY_EFFECTIVE | MOVE_RESULT_SUPER_EFFECTIVE);
+        *resultFlags |= MOVE_RESULT_DOESNT_AFFECT_FOE;
+        *resultFlags &= ~(MOVE_RESULT_NOT_VERY_EFFECTIVE | MOVE_RESULT_SUPER_EFFECTIVE);
         gBattleStruct->blunderPolicy = FALSE; // Don't activate if missed
     }
     else if (modifier == UQ_4_12(1.0))
     {
-        gBattleStruct->moveResultFlags[battler] &= ~(MOVE_RESULT_NOT_VERY_EFFECTIVE | MOVE_RESULT_SUPER_EFFECTIVE | MOVE_RESULT_DOESNT_AFFECT_FOE);
+        *resultFlags &= ~(MOVE_RESULT_NOT_VERY_EFFECTIVE | MOVE_RESULT_SUPER_EFFECTIVE | MOVE_RESULT_DOESNT_AFFECT_FOE);
     }
     else if (modifier > UQ_4_12(1.0))
     {
-        gBattleStruct->moveResultFlags[battler] |= MOVE_RESULT_SUPER_EFFECTIVE;
-        gBattleStruct->moveResultFlags[battler] &= ~(MOVE_RESULT_NOT_VERY_EFFECTIVE | MOVE_RESULT_DOESNT_AFFECT_FOE);
+        *resultFlags |= MOVE_RESULT_SUPER_EFFECTIVE;
+        *resultFlags &= ~(MOVE_RESULT_NOT_VERY_EFFECTIVE | MOVE_RESULT_DOESNT_AFFECT_FOE);
     }
     else //if (modifier < UQ_4_12(1.0))
     {
-        gBattleStruct->moveResultFlags[battler] |= MOVE_RESULT_NOT_VERY_EFFECTIVE;
-        gBattleStruct->moveResultFlags[battler] &= ~(MOVE_RESULT_SUPER_EFFECTIVE | MOVE_RESULT_DOESNT_AFFECT_FOE);
+        *resultFlags |= MOVE_RESULT_NOT_VERY_EFFECTIVE;
+        *resultFlags &= ~(MOVE_RESULT_SUPER_EFFECTIVE | MOVE_RESULT_DOESNT_AFFECT_FOE);
     }
 }
 
@@ -10760,7 +10760,7 @@ uq4_12_t CalcTypeEffectivenessMultiplier(u32 move, u32 moveType, u32 battlerAtk,
     }
 
     if (recordAbilities)
-        UpdateMoveResultFlags(modifier, battlerDef);
+        UpdateMoveResultFlags(modifier, &gBattleStruct->moveResultFlags[battlerDef]);
     return modifier;
 }
 
@@ -10781,7 +10781,6 @@ uq4_12_t CalcPartyMonTypeEffectivenessMultiplier(u16 move, u16 speciesDef, u16 a
             modifier = UQ_4_12(0.0);
     }
 
-    UpdateMoveResultFlags(modifier, speciesDef);
     return modifier;
 }