Mike Magruder
4048565e87
A real breakpoint makes entries in the breakpoint filter for all offsets at the given line. Various flow control commands will also use the breakpoint filter to add and remove temporary "internal breakpoints" required during the flow operation. Ensure that we never remove a breakpoint filter entry if there was already one there due to a breakpoint (or really any other reason).
258 linhas
9.8 KiB
C++
258 linhas
9.8 KiB
C++
/*
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+----------------------------------------------------------------------+
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| HipHop for PHP |
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+----------------------------------------------------------------------+
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| Copyright (c) 2010-2013 Facebook, Inc. (http://www.facebook.com) |
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+----------------------------------------------------------------------+
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| This source file is subject to version 3.01 of the PHP license, |
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| that is bundled with this package in the file LICENSE, and is |
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| available through the world-wide-web at the following url: |
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| http://www.php.net/license/3_01.txt |
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| If you did not receive a copy of the PHP license and are unable to |
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| obtain it through the world-wide-web, please send a note to |
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| license@php.net so we can mail you a copy immediately. |
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+----------------------------------------------------------------------+
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*/
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#include "hphp/runtime/debugger/cmd/cmd_flow_control.h"
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#include "hphp/runtime/vm/debugger_hook.h"
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namespace HPHP { namespace Eval {
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///////////////////////////////////////////////////////////////////////////////
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TRACE_SET_MOD(debuggerflow);
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CmdFlowControl::~CmdFlowControl() {
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// Remove any location filter that may have been setup.
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removeLocationFilter();
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}
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void CmdFlowControl::sendImpl(DebuggerThriftBuffer &thrift) {
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DebuggerCommand::sendImpl(thrift);
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thrift.write(m_count);
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thrift.write(m_smallStep);
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}
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void CmdFlowControl::recvImpl(DebuggerThriftBuffer &thrift) {
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DebuggerCommand::recvImpl(thrift);
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thrift.read(m_count);
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thrift.read(m_smallStep);
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}
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void CmdFlowControl::onClientImpl(DebuggerClient &client) {
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if (DebuggerCommand::displayedHelp(client)) return;
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client.setFrame(0);
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if (client.argCount() > 1) {
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help(client);
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return;
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}
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if (client.argCount() == 1) {
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string snum = client.argValue(1);
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if (!DebuggerClient::IsValidNumber(snum)) {
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client.error("Count needs to be a number.");
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return;
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}
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m_count = atoi(snum.c_str());
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if (m_count < 1) {
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client.error("Count needs to be a positive number.");
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return;
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}
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}
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m_smallStep = client.getDebuggerClientSmallStep();
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client.sendToServer(this);
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throw DebuggerConsoleExitException();
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}
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bool CmdFlowControl::onServer(DebuggerProxy &proxy) {
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// Flow control cmds do their work in onSetup() and onBeginInterrupt(), so
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// there is no real work to do in here.
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return true;
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}
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// Setup the last location filter on the VM context for all offsets covered by
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// the current source line. This will short-circuit the work done in
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// phpDebuggerOpcodeHook() and ensure we don't interrupt on this source line.
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// We exclude continuation opcodes which transfer control out of the function,
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// which allows cmds to get a chance to alter their behavior when those opcodes
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// are encountered.
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void CmdFlowControl::installLocationFilterForLine(InterruptSite *site) {
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// We may be stopped at a place with no source info.
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if (!site || !site->valid()) return;
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if (g_vmContext->m_lastLocFilter) {
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g_vmContext->m_lastLocFilter->clear();
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} else {
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g_vmContext->m_lastLocFilter = new PCFilter();
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}
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TRACE(3, "Prepare location filter for %s:%d, unit %p:\n",
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site->getFile(), site->getLine0(), site->getUnit());
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OffsetRangeVec ranges;
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const auto unit = site->getUnit();
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if (m_smallStep) {
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// Get offset range for the pc only.
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OffsetRange range;
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if (unit->getOffsetRange(site->getCurOffset(), range)) {
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ranges.push_back(range);
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}
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} else {
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// Get offset ranges for the whole line.
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// We use line1 here because it seems to be working better than line0
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// in a handful of cases for our bytecode-source mapping.
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if (!unit->getOffsetRanges(site->getLine1(), ranges)) {
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ranges.clear();
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}
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}
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auto excludeContinuationReturns = [] (Op op) {
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return (op != OpContSuspend) &&
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(op != OpContSuspendK) &&
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(op != OpContRetC);
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};
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g_vmContext->m_lastLocFilter->addRanges(unit, ranges,
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excludeContinuationReturns);
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}
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void CmdFlowControl::removeLocationFilter() {
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if (g_vmContext->m_lastLocFilter) {
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delete g_vmContext->m_lastLocFilter;
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g_vmContext->m_lastLocFilter = nullptr;
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}
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}
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bool CmdFlowControl::hasStepOuts() {
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return m_stepOut1.valid() || m_stepOut2.valid();
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}
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bool CmdFlowControl::atStepOutOffset(Unit* unit, Offset o) {
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return m_stepOut1.at(unit, o) || m_stepOut2.at(unit, o);
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}
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// Place internal breakpoints to get out of the current function. This may place
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// multiple internal breakpoints, and it may place them more than one frame up.
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// Some instructions can cause PHP to be invoked without an explicit call. A set
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// which causes a destructor to run, a iteration init which causes an object's
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// next() method to run, a RetC which causes destructors to run, etc. This
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// recgonizes such cases and ensures we have internal breakpoints to cover the
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// destination(s) of such instructions.
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void CmdFlowControl::setupStepOuts() {
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// Existing step outs should be cleaned up before making new ones.
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assert(!hasStepOuts());
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ActRec* fp = g_vmContext->getFP();
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assert(fp);
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Offset returnOffset;
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bool fromVMEntry;
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while (!hasStepOuts()) {
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fp = g_vmContext->getPrevVMState(fp, &returnOffset, nullptr, &fromVMEntry);
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// If we've run off the top of the stack, just return having setup no
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// step outs. This will cause cmds like Next and Out to just let the program
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// run, which is appropriate.
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if (!fp) break;
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Unit* returnUnit = fp->m_func->unit();
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PC returnPC = returnUnit->at(returnOffset);
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TRACE(2, "CmdFlowControl::setupStepOuts: at '%s' offset %d opcode %s\n",
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fp->m_func->fullName()->data(), returnOffset,
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opcodeToName(toOp(*returnPC)));
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// Don't step out to generated functions, keep looking.
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if (fp->m_func->line1() == 0) continue;
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if (fromVMEntry) {
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TRACE(2, "CmdFlowControl::setupStepOuts: VM entry\n");
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// We only execute this for opcodes which invoke more PHP, and that does
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// not include switches. Thus, we'll have at most two destinations.
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assert(!isSwitch(*returnPC) && (numSuccs((Op*)returnPC) <= 2));
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// Set an internal breakpoint after the instruction if it can fall thru.
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if (instrAllowsFallThru(toOp(*returnPC))) {
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Offset nextOffset = returnOffset + instrLen((Op*)returnPC);
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TRACE(2, "CmdFlowControl: step out to '%s' offset %d (fall-thru)\n",
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fp->m_func->fullName()->data(), nextOffset);
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m_stepOut1 = StepDestination(returnUnit, nextOffset);
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}
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// Set an internal breakpoint at the target of a control flow instruction.
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// A good example of a control flow op that invokes PHP is IterNext.
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if (instrIsControlFlow(toOp(*returnPC))) {
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Offset target = instrJumpTarget((Op*)returnPC, 0);
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if (target != InvalidAbsoluteOffset) {
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Offset targetOffset = returnOffset + target;
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TRACE(2, "CmdFlowControl: step out to '%s' offset %d (jump target)\n",
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fp->m_func->fullName()->data(), targetOffset);
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m_stepOut2 = StepDestination(returnUnit, targetOffset);
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}
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}
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// If we have no place to step out to, then unwind another frame and try
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// again. The most common case that leads here is Ret*, which does not
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// fall-thru and has no encoded target.
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} else {
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TRACE(2, "CmdFlowControl: step out to '%s' offset %d\n",
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fp->m_func->fullName()->data(), returnOffset);
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m_stepOut1 = StepDestination(returnUnit, returnOffset);
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}
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}
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}
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void CmdFlowControl::cleanupStepOuts() {
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if (m_stepOut1.valid()) {
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m_stepOut1 = StepDestination();
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}
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if (m_stepOut2.valid()) {
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m_stepOut2 = StepDestination();
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}
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}
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///////////////////////////////////////////////////////////////////////////////
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// StepDestination
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//
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// NB: a StepDestination also manages an internal breakpoint at the
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// given location. If there is already an internal breakpoint set when
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// a StepDestination is constructed then it will not remove the
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// breakpoint when it is destructed. The move assignment operator
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// handles the transfer of ownership, and we delete the copy
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// constructor/assignment operators explictly to ensure no two
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// StepDestinations believe they can remove the same internal
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// breakpoint.
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//
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// We can manage internal breakpoints without a true refcount like
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// this because no other operation can manipulate the breakpoint
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// filter while a single flow control command is active, and because
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// the lifetime of a StepDestination is scoped by the lifetime of its
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// flow control command.
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CmdFlowControl::StepDestination::StepDestination() :
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m_unit(nullptr), m_offset(InvalidAbsoluteOffset),
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m_ownsInternalBreakpoint(false)
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{
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}
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CmdFlowControl::StepDestination::StepDestination(const Unit* unit,
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Offset offset) :
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m_unit(unit), m_offset(offset)
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{
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m_ownsInternalBreakpoint = !phpHasBreakpoint(m_unit, m_offset);
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if (m_ownsInternalBreakpoint) phpAddBreakPoint(m_unit, m_offset);
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}
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CmdFlowControl::StepDestination::StepDestination(StepDestination&& other) {
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*this = std::move(other);
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}
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CmdFlowControl::StepDestination&
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CmdFlowControl::StepDestination::operator=(StepDestination&& other) {
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if (this != &other) {
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if (m_ownsInternalBreakpoint) phpRemoveBreakPoint(m_unit, m_offset);
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m_unit = other.m_unit;
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m_offset = other.m_offset;
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m_ownsInternalBreakpoint = other.m_ownsInternalBreakpoint;
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other.m_unit = nullptr;
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other.m_offset = InvalidAbsoluteOffset;
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other.m_ownsInternalBreakpoint = false;
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}
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return *this;
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}
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CmdFlowControl::StepDestination::~StepDestination() {
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if (m_ownsInternalBreakpoint) phpRemoveBreakPoint(m_unit, m_offset);
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}
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///////////////////////////////////////////////////////////////////////////////
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}}
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