// Handle a continue cmd, or setup stepping.
void DebuggerProxy::processFlowControl(CmdInterrupt &cmd) {
TRACE(2, "DebuggerProxy::processFlowControl\n");
switch (m_flow->getType()) {
case DebuggerCommand::KindOfContinue:
if (!m_flow->decCount()) {
m_flow.reset();
}
break;
case DebuggerCommand::KindOfStep:
{
// allows the breakpoint to be hit again when returns
// from function call
BreakPointInfoPtr bp = getBreakPointAtCmd(cmd);
if (bp) {
bp->setBreakable(getRealStackDepth());
}
break;
}
case DebuggerCommand::KindOfOut:
case DebuggerCommand::KindOfNext:
m_flow->setStackDepth(getStackDepth());
m_flow->setVMDepth(g_vmContext->m_nesting);
m_flow->setFileLine(cmd.getFileLine());
break;
default:
assert(false);
break;
}
}
void CmdNext::onBeginInterrupt(DebuggerProxy &proxy, CmdInterrupt &interrupt) {
TRACE(2, "CmdNext::onBeginInterrupt\n");
assert(!m_complete); // Complete cmds should not be asked to do work.
if (interrupt.getInterruptType() == ExceptionThrown) {
// If an exception is thrown we turn interrupts on to ensure we stop when
// control reaches the first catch clause.
removeLocationFilter();
m_needsVMInterrupt = true;
return;
}
int currentVMDepth = g_vmContext->m_nesting;
int currentStackDepth = proxy.getStackDepth();
if ((currentVMDepth < m_vmDepth) ||
((currentVMDepth == m_vmDepth) && (currentStackDepth <= m_stackDepth))) {
// We're at the same depth as when we started, or perhaps even shallower, so
// there's no need for any step out breakpoint anymore.
cleanupStepOut();
if (m_loc != interrupt.getFileLine()) {
TRACE(2, "CmdNext: same depth, off original line.\n");
m_complete = (decCount() == 0);
}
if (!m_complete) {
TRACE(2, "CmdNext: not complete, filter new line and keep stepping.\n");
m_loc = interrupt.getFileLine();
installLocationFilterForLine(interrupt.getSite());
m_needsVMInterrupt = true;
}
} else {
// Deeper, so let's setup a step out operation and turn interrupts off.
if (!m_stepOutUnit) {
// We can nuke the entire location filter here since we'll re-install it
// when we get back to the old level. Keeping it installed may be more
// efficient if we were on a large line, but there is a penalty for every
// opcode executed while it's installed and that's bad if there's a lot of
// code called from that line.
removeLocationFilter();
setupStepOut();
}
m_needsVMInterrupt = false;
}
}
void CmdNext::onSetup(DebuggerProxy& proxy, CmdInterrupt& interrupt) {
TRACE(2, "CmdNext::onSetup\n");
assert(!m_complete); // Complete cmds should not be asked to do work.
m_stackDepth = proxy.getStackDepth();
m_vmDepth = g_vmContext->m_nesting;
m_loc = interrupt.getFileLine();
ActRec *fp = g_vmContext->getFP();
assert(fp); // All interrupts which reach a flow cmd have an AR.
PC pc = g_vmContext->getPC();
stepCurrentLine(interrupt, fp, pc);
}
void CmdNext::onSetup(DebuggerProxy &proxy, CmdInterrupt &interrupt) {
TRACE(2, "CmdNext::onSetup\n");
assert(!m_complete); // Complete cmds should not be asked to do work.
CmdFlowControl::onSetup(proxy, interrupt);
m_stackDepth = proxy.getStackDepth();
m_vmDepth = g_vmContext->m_nesting;
m_loc = interrupt.getFileLine();
// Start by single-stepping the current line.
installLocationFilterForLine(interrupt.getSite());
m_needsVMInterrupt = true;
}
void CmdNext::onSetup(DebuggerProxy& proxy, CmdInterrupt& interrupt) {
TRACE(2, "CmdNext::onSetup\n");
assertx(!m_complete); // Complete cmds should not be asked to do work.
m_stackDepth = proxy.getStackDepth();
m_vmDepth = g_context->m_nesting;
m_loc = interrupt.getFileLine();
ActRec *fp = vmfp();
if (!fp) {
// If we have no frame just wait for the next instruction to be interpreted.
m_needsVMInterrupt = true;
return;
}
PC pc = vmpc();
stepCurrentLine(interrupt, fp, pc);
}
// Determine if an outstanding flow control cmd has run it's course and we
// should stop execution.
bool DebuggerProxy::breakByFlowControl(CmdInterrupt &cmd) {
TRACE(2, "DebuggerProxy::breakByFlowControl\n");
switch (m_flow->getType()) {
case DebuggerCommand::KindOfStep: {
if (!m_flow->decCount()) {
// if the line changes and the stack depth is the same
// pop the breakpoint depth stack
m_flow.reset();
return true;
}
break;
}
case DebuggerCommand::KindOfNext: {
int currentVMDepth = g_vmContext->m_nesting;
int currentStackDepth = getStackDepth();
if (currentVMDepth <= m_flow->getVMDepth() &&
currentStackDepth <= m_flow->getStackDepth() &&
m_flow->getFileLine() != cmd.getFileLine()) {
if (!m_flow->decCount()) {
m_flow.reset();
return true;
}
}
break;
}
case DebuggerCommand::KindOfOut: {
int currentVMDepth = g_vmContext->m_nesting;
int currentStackDepth = getStackDepth();
if (currentVMDepth < m_flow->getVMDepth()) {
// Cut corner here, just break when cross VM boundary no matter how
// many levels we want to go out of
m_flow.reset();
return true;
} else if (m_flow->getStackDepth() - currentStackDepth >=
m_flow->getCount()) {
m_flow.reset();
return true;
}
break;
}
default:
break;
}
return false;
}
void CmdNext::onBeginInterrupt(DebuggerProxy& proxy, CmdInterrupt& interrupt) {
TRACE(2, "CmdNext::onBeginInterrupt\n");
assertx(!m_complete); // Complete cmds should not be asked to do work.
ActRec *fp = vmfp();
if (!fp) {
// If we have no frame just wait for the next instruction to be interpreted.
m_needsVMInterrupt = true;
return;
}
PC pc = vmpc();
Unit* unit = fp->m_func->unit();
Offset offset = unit->offsetOf(pc);
TRACE(2, "CmdNext: pc %p, opcode %s at '%s' offset %d\n",
pc,
opcodeToName(peek_op(pc)),
fp->m_func->fullName()->data(),
offset);
int currentVMDepth = g_context->m_nesting;
int currentStackDepth = proxy.getStackDepth();
TRACE(2, "CmdNext: original depth %d:%d, current depth %d:%d\n",
m_vmDepth, m_stackDepth, currentVMDepth, currentStackDepth);
// Where are we on the stack now vs. when we started? Breaking the answer down
// into distinct variables helps the clarity of the algorithm below.
bool deeper = false;
bool originalDepth = false;
if ((currentVMDepth == m_vmDepth) && (currentStackDepth == m_stackDepth)) {
originalDepth = true;
} else if ((currentVMDepth > m_vmDepth) ||
((currentVMDepth == m_vmDepth) &&
(currentStackDepth > m_stackDepth))) {
deeper = true;
}
m_needsVMInterrupt = false; // Will be set again below if still needed.
// First consider if we've got internal breakpoints setup. These are used when
// we can make an accurate prediction of where execution should flow,
// eventually, and when we want to let the program run normally until we get
// there.
if (hasStepOuts() || hasStepResumable()) {
TRACE(2, "CmdNext: checking internal breakpoint(s)\n");
if (atStepOutOffset(unit, offset)) {
if (deeper) return; // Recursion
TRACE(2, "CmdNext: hit step-out\n");
} else if (atStepResumableOffset(unit, offset)) {
if (m_stepResumableId != getResumableId(fp)) return;
TRACE(2, "CmdNext: hit step-cont\n");
// We're in the resumable we expect. This may be at a
// different stack depth, though, especially if we've moved from
// the original function to the resumable. Update the depth
// accordingly.
if (!originalDepth) {
m_vmDepth = currentVMDepth;
m_stackDepth = currentStackDepth;
deeper = false;
originalDepth = true;
}
} else if (interrupt.getInterruptType() == ExceptionHandler) {
// Entering an exception handler may take us someplace we weren't
// expecting. Adjust internal breakpoints accordingly. First case is easy.
if (deeper) {
TRACE(2, "CmdNext: exception handler, deeper\n");
return;
}
// For step-conts, we ignore handlers at the original level if we're not
// in the original resumable. We don't care about exception handlers
// in resumables being driven at the same level.
if (hasStepResumable() && originalDepth &&
(m_stepResumableId != getResumableId(fp))) {
TRACE(2, "CmdNext: exception handler, original depth, wrong cont\n");
return;
}
// Sometimes we have handlers in generated code, i.e., Continuation::next.
// These just help propagate exceptions so ignore those.
if (fp->m_func->line1() == 0) {
TRACE(2, "CmdNext: exception handler, ignoring func with no source\n");
return;
}
if (fp->m_func->isBuiltin()) {
TRACE(2, "CmdNext: exception handler, ignoring builtin functions\n");
return;
}
TRACE(2, "CmdNext: exception handler altering expected flow\n");
} else {
// We have internal breakpoints setup, but we haven't hit one yet. Keep
// running until we reach one.
TRACE(2, "CmdNext: waiting to hit internal breakpoint...\n");
return;
}
// We've hit one internal breakpoint at a useful place, or decided we don't,
// need them, so we can remove them all now.
cleanupStepOuts();
cleanupStepResumable();
}
if (interrupt.getInterruptType() == ExceptionHandler) {
// If we're about to enter an exception handler we turn interrupts on to
// ensure we stop when control reaches the handler. The normal logic below
// will decide if we're done at that point or not.
TRACE(2, "CmdNext: exception handler\n");
removeLocationFilter();
m_needsVMInterrupt = true;
return;
}
if (m_skippingAwait) {
m_skippingAwait = false;
stepAfterAwait();
return;
}
if (deeper) {
TRACE(2, "CmdNext: deeper, setup step out to get back to original line\n");
setupStepOuts();
// We can nuke the entire location filter here since we'll re-install it
// when we get back to the old level. Keeping it installed may be more
// efficient if we were on a large line, but there is a penalty for every
// opcode executed while it's installed and that's bad if there's a lot of
// code called from that line.
removeLocationFilter();
return;
}
if (originalDepth && (m_loc == interrupt.getFileLine())) {
TRACE(2, "CmdNext: not complete, still on same line\n");
stepCurrentLine(interrupt, fp, pc);
return;
}
TRACE(2, "CmdNext: operation complete.\n");
m_complete = (decCount() == 0);
if (!m_complete) {
TRACE(2, "CmdNext: repeat count > 0, start fresh.\n");
onSetup(proxy, interrupt);
}
}
