diff options
| -rw-r--r-- | engines/sci/engine/vm.cpp | 13 | ||||
| -rw-r--r-- | engines/sci/engine/vm_types.h | 4 |
2 files changed, 11 insertions, 6 deletions
diff --git a/engines/sci/engine/vm.cpp b/engines/sci/engine/vm.cpp index 9e7ade1f74..36512f96ed 100644 --- a/engines/sci/engine/vm.cpp +++ b/engines/sci/engine/vm.cpp @@ -39,8 +39,8 @@ namespace Sci { -reg_t NULL_REG = {0, 0}; -reg_t SIGNAL_REG = {0, SIGNAL_OFFSET}; +const reg_t NULL_REG = {0, 0}; +const reg_t SIGNAL_REG = {0, SIGNAL_OFFSET}; //#define VM_DEBUG_SEND @@ -57,15 +57,20 @@ static bool breakpointFlag = false; // FIXME: Avoid non-const global vars #ifndef DISABLE_VALIDATIONS static reg_t &validate_property(Object *obj, int index) { + // A static dummy reg_t, which we return if obj or index turn out to be + // invalid. Note that we cannot just return NULL_REG, because client code + // may modify the value of the return reg_t. + static reg_t dummyReg = NULL_REG; + if (!obj) { debugC(2, kDebugLevelVM, "[VM] Sending to disposed object!\n"); - return NULL_REG; + return dummyReg; } if (index < 0 || (uint)index >= obj->_variables.size()) { debugC(2, kDebugLevelVM, "[VM] Invalid property #%d (out of [0..%d]) requested!\n", index, obj->_variables.size()); - return NULL_REG; + return dummyReg; } return obj->_variables[index]; diff --git a/engines/sci/engine/vm_types.h b/engines/sci/engine/vm_types.h index 93378fe3d1..c62d0bddcb 100644 --- a/engines/sci/engine/vm_types.h +++ b/engines/sci/engine/vm_types.h @@ -80,8 +80,8 @@ static inline reg_t make_reg(SegmentId segment, uint16 offset) { return r; } -extern reg_t NULL_REG; -extern reg_t SIGNAL_REG; +extern const reg_t NULL_REG; +extern const reg_t SIGNAL_REG; } // End of namespace Sci |