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Fix skipping of if statements and loops #381

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Merged
merged 4 commits into from
Dec 17, 2023
Merged

Fix skipping of if statements and loops #381

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b098cf6
fix #378: Skip loops in if statements correctly
adazem009 Dec 17, 2023
fa83e27
fix #379: Skip if statements and loops in repeat until loop correctly
adazem009 Dec 17, 2023
92a8a2b
fix #380: Fix skipping of nested if statements and loops in else branch
adazem009 Dec 17, 2023
afef8a0
Fix build errors in VirtualMachinePrivate
adazem009 Dec 17, 2023
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44 changes: 35 additions & 9 deletions src/engine/virtualmachine_p.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -236,25 +236,40 @@ unsigned int *VirtualMachinePrivate::run(unsigned int *pos, bool reset)
checkpoint = pos - 1;
DISPATCH();

do_if:
do_if : {
if (!READ_LAST_REG()->toBool()) {
unsigned int ifCounter = 1;
while ((*pos != OP_ELSE && *pos != OP_ENDIF) || (ifCounter > 0)) {
while (!((*pos == OP_ELSE && ifCounter == 1) || (*pos == OP_ENDIF && ifCounter == 0))) {
pos += instruction_arg_count[*pos++];

if (*pos == OP_IF)
if ((*pos == OP_IF) || (*pos == OP_FOREVER_LOOP) || (*pos == OP_REPEAT_LOOP) || (*pos == OP_UNTIL_LOOP))
ifCounter++;
else if ((*pos == OP_ELSE) || (*pos == OP_ENDIF))
else if ((*pos == OP_ENDIF) || (*pos == OP_LOOP_END)) {
assert(ifCounter > 0);
ifCounter--;
}
}
}
FREE_REGS(1);
DISPATCH();
}

do_else:
while (*pos != OP_ENDIF)
do_else : {
unsigned int ifCounter = 1;
while (!(*pos == OP_ENDIF && ifCounter == 0)) {
pos += instruction_arg_count[*pos++];

if ((*pos == OP_IF) || (*pos == OP_FOREVER_LOOP) || (*pos == OP_REPEAT_LOOP) || (*pos == OP_UNTIL_LOOP))
ifCounter++;
else if ((*pos == OP_ENDIF) || (*pos == OP_LOOP_END)) {
assert(ifCounter > 0);
ifCounter--;
}

assert(!(*pos == OP_ELSE && ifCounter == 1));
}
}

do_endif:
DISPATCH();

Expand All @@ -275,10 +290,12 @@ unsigned int *VirtualMachinePrivate::run(unsigned int *pos, bool reset)
while ((*loopEnd != OP_LOOP_END) || (loopCounter > 0)) {
loopEnd += instruction_arg_count[*loopEnd++];

if ((*loopEnd == OP_FOREVER_LOOP) || (*loopEnd == OP_REPEAT_LOOP) || (*loopEnd == OP_UNTIL_LOOP))
if ((*loopEnd == OP_IF) || (*loopEnd == OP_FOREVER_LOOP) || (*loopEnd == OP_REPEAT_LOOP) || (*loopEnd == OP_UNTIL_LOOP))
loopCounter++;
else if (*loopEnd == OP_LOOP_END)
else if ((*loopEnd == OP_ENDIF) || (*loopEnd == OP_LOOP_END)) {
assert(loopCounter > 0);
loopCounter--;
}
}
pos = loopEnd;
} else {
Expand Down Expand Up @@ -317,8 +334,17 @@ do_repeat_loop_index1 : {
pos = loopStart;
} else {
pos = loopStart;
while (*pos != OP_LOOP_END)
unsigned int loopCounter = 1;
while ((*pos != OP_LOOP_END) || (loopCounter > 0)) {
pos += instruction_arg_count[*pos++];

if ((*pos == OP_IF) || (*pos == OP_FOREVER_LOOP) || (*pos == OP_REPEAT_LOOP) || (*pos == OP_UNTIL_LOOP))
loopCounter++;
else if ((*pos == OP_ENDIF) || (*pos == OP_LOOP_END)) {
assert(loopCounter > 0);
loopCounter--;
}
}
}
FREE_REGS(1);
DISPATCH();
Expand Down
33 changes: 33 additions & 0 deletions test/virtual_machine/virtual_machine_test.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1626,3 +1626,36 @@ TEST(VirtualMachineTest, NoCrashInNestedIfStatementsWithLoop)
vm.run();
ASSERT_EQ(vm.registerCount(), 0);
}

TEST(VirtualMachineTest, NoCrashInNestedIfStatementsWithLoopAndIfElse)
{
// Regtest for #378
static unsigned int bytecode[] = { OP_START, OP_NULL, OP_IF, OP_NULL, OP_REPEAT_LOOP, OP_NULL, OP_IF, OP_ELSE, OP_ENDIF, OP_LOOP_END, OP_ENDIF, OP_HALT };

VirtualMachine vm(nullptr, nullptr, nullptr);
vm.setBytecode(bytecode);
vm.run();
ASSERT_EQ(vm.registerCount(), 0);
}

TEST(VirtualMachineTest, NoCrashInNestedLoopsInRepeatUntilLoop)
{
// Regtest for #379
static unsigned int bytecode[] = { OP_START, OP_NULL, OP_NOT, OP_IF, OP_ELSE, OP_NULL, OP_REPEAT_LOOP, OP_NULL, OP_IF, OP_ENDIF, OP_LOOP_END, OP_ENDIF, OP_HALT };

VirtualMachine vm(nullptr, nullptr, nullptr);
vm.setBytecode(bytecode);
vm.run();
ASSERT_EQ(vm.registerCount(), 0);
}

TEST(VirtualMachineTest, NoCrashInNestedLoopsInIfElseStatements)
{
// Regtest for #380
static unsigned int bytecode[] = { OP_START, OP_UNTIL_LOOP, OP_NULL, OP_NOT, OP_BEGIN_UNTIL_LOOP, OP_NULL, OP_REPEAT_LOOP, OP_LOOP_END, OP_LOOP_END, OP_HALT };

VirtualMachine vm(nullptr, nullptr, nullptr);
vm.setBytecode(bytecode);
vm.run();
ASSERT_EQ(vm.registerCount(), 0);
}