Initial checkin of the LLVM source-level debugger. This is still not finished,
by any stretch of the imagination, but it is pretty cool and works :)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@10685 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Debugger/UnixLocalInferiorProcess.cpp b/lib/Debugger/UnixLocalInferiorProcess.cpp
new file mode 100644
index 0000000..ff9a15a
--- /dev/null
+++ b/lib/Debugger/UnixLocalInferiorProcess.cpp
@@ -0,0 +1,911 @@
+//===-- UnixLocalInferiorProcess.cpp - A Local process on a Unixy system --===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file provides one implementation of the InferiorProcess class, which is
+// designed to be used on unixy systems (those that support pipe, fork, exec,
+// and signals).
+//
+// When the process is started, the debugger creates a pair of pipes, forks, and
+// makes the child starts executing the program. The child executes the process
+// with an IntrinsicLowering instance that turns debugger intrinsics into actual
+// callbacks.
+//
+// This target takes advantage of the fact that the Module* addresses in the
+// parent and the Module* addresses in the child will be the same, due to the
+// use of fork(). As such, global addresses looked up in the child can be sent
+// over the pipe to the debugger.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Debugger/InferiorProcess.h"
+#include "llvm/IntrinsicLowering.h"
+#include "llvm/Constant.h"
+#include "llvm/Module.h"
+#include "llvm/ModuleProvider.h"
+#include "llvm/Type.h"
+#include "llvm/iOther.h"
+#include "llvm/ExecutionEngine/GenericValue.h"
+#include "llvm/ExecutionEngine/ExecutionEngine.h"
+#include "Support/FileUtilities.h"
+#include "Support/StringExtras.h"
+#include <cerrno>
+#include <unistd.h> // Unix specific debugger support
+#include <sys/types.h>
+#include <sys/wait.h>
+using namespace llvm;
+
+// runChild - Entry point for the child process.
+static void runChild(Module *M, const std::vector<std::string> &Arguments,
+ const char * const *envp,
+ FDHandle ReadFD, FDHandle WriteFD);
+
+//===----------------------------------------------------------------------===//
+// Parent/Child Pipe Protocol
+//===----------------------------------------------------------------------===//
+//
+// The parent/child communication protocol is designed to have the child process
+// responding to requests that the debugger makes. Whenever the child process
+// has stopped (due to a break point, single stepping, etc), the child process
+// enters a message processing loop, where it reads and responds to commands
+// until the parent decides that it wants to continue execution in some way.
+//
+// Whenever the child process stops, it notifies the debugger by sending an
+// character over the wire.
+//
+
+namespace {
+ /// LocationToken - Objects of this type are sent across the pipe from the
+ /// child to the parent to indicate where various stack frames are located.
+ struct LocationToken {
+ unsigned Line, Col;
+ const GlobalVariable *File;
+ LocationToken(unsigned L = 0, unsigned C = 0, const GlobalVariable *F = 0)
+ : Line(L), Col(C), File(F) {}
+ };
+}
+
+// Once the debugger process has received the LocationToken, it can make
+// requests of the child by sending one of the following enum values followed by
+// any data required by that command. The child responds with data appropriate
+// to the command.
+//
+namespace {
+ /// CommandID - This enum defines all of the commands that the child process
+ /// can respond to. The actual expected data and responses are defined as the
+ /// enum values are defined.
+ ///
+ enum CommandID {
+ //===------------------------------------------------------------------===//
+ // Execution commands - These are sent to the child to from the debugger to
+ // get it to do certain things.
+ //
+
+ // StepProgram: void->char - This command causes the program to continue
+ // execution, but stop as soon as it reaches another stoppoint.
+ StepProgram,
+
+ // FinishProgram: FrameDesc*->char - This command causes the program to
+ // continue execution until the specified function frame returns.
+ FinishProgram,
+
+ // ContProgram: void->char - This command causes the program to continue
+ // execution, stopping at some point in the future.
+ ContProgram,
+
+ // GetSubprogramDescriptor: FrameDesc*->GlobalValue* - This command returns
+ // the GlobalValue* descriptor object for the specified stack frame.
+ GetSubprogramDescriptor,
+
+ // GetParentFrame: FrameDesc*->FrameDesc* - This command returns the frame
+ // descriptor for the parent stack frame to the specified one, or null if
+ // there is none.
+ GetParentFrame,
+
+ // GetFrameLocation - FrameDesc*->LocationToken - This command returns the
+ // location that a particular stack frame is stopped at.
+ GetFrameLocation,
+
+ // AddBreakpoint - LocationToken->unsigned - This command instructs the
+ // target to install a breakpoint at the specified location.
+ AddBreakpoint,
+
+ // RemoveBreakpoint - unsigned->void - This command instructs the target to
+ // remove a breakpoint.
+ RemoveBreakpoint,
+ };
+}
+
+
+
+
+//===----------------------------------------------------------------------===//
+// Parent Process Code
+//===----------------------------------------------------------------------===//
+
+namespace {
+ class IP : public InferiorProcess {
+ // ReadFD, WriteFD - The file descriptors to read/write to the inferior
+ // process.
+ FDHandle ReadFD, WriteFD;
+
+ // ChildPID - The unix PID of the child process we forked.
+ mutable pid_t ChildPID;
+ public:
+ IP(Module *M, const std::vector<std::string> &Arguments,
+ const char * const *envp);
+ ~IP();
+
+ std::string getStatus() const;
+
+ /// Execution method implementations...
+ virtual void stepProgram();
+ virtual void finishProgram(void *Frame);
+ virtual void contProgram();
+
+
+ // Stack frame method implementations...
+ virtual void *getPreviousFrame(void *Frame) const;
+ virtual const GlobalVariable *getSubprogramDesc(void *Frame) const;
+ virtual void getFrameLocation(void *Frame, unsigned &LineNo,
+ unsigned &ColNo,
+ const GlobalVariable *&SourceDesc) const;
+
+ // Breakpoint implementation methods
+ virtual unsigned addBreakpoint(unsigned LineNo, unsigned ColNo,
+ const GlobalVariable *SourceDesc);
+ virtual void removeBreakpoint(unsigned ID);
+
+
+ private:
+ /// startChild - This starts up the child process, and initializes the
+ /// ChildPID member.
+ ///
+ void startChild(Module *M, const std::vector<std::string> &Arguments,
+ const char * const *envp);
+
+ /// killChild - Kill or reap the child process. This throws the
+ /// InferiorProcessDead exception an exit code if the process had already
+ /// died, otherwise it just kills it and returns.
+ void killChild() const;
+
+ private:
+ // Methods for communicating with the child process. If the child exits or
+ // dies while attempting to communicate with it, ChildPID is set to zero and
+ // an exception is thrown.
+
+ /// readFromChild - Low-level primitive to read some data from the child,
+ /// throwing an exception if it dies.
+ void readFromChild(void *Buffer, unsigned Size) const;
+
+ /// writeToChild - Low-level primitive to send some data to the child
+ /// process, throwing an exception if the child died.
+ void writeToChild(void *Buffer, unsigned Size) const;
+
+ /// sendCommand - Send a command token and the request data to the child.
+ ///
+ void sendCommand(CommandID Command, void *Data, unsigned Size) const;
+
+ /// waitForStop - This method waits for the child process to reach a stop
+ /// point.
+ void waitForStop();
+ };
+}
+
+// create - This is the factory method for the InferiorProcess class. Since
+// there is currently only one subclass of InferiorProcess, we just define it
+// here.
+InferiorProcess *
+InferiorProcess::create(Module *M, const std::vector<std::string> &Arguments,
+ const char * const *envp) {
+ return new IP(M, Arguments, envp);
+}
+
+/// IP constructor - Create some pipes, them fork a child process. The child
+/// process should start execution of the debugged program, but stop at the
+/// first available opportunity.
+IP::IP(Module *M, const std::vector<std::string> &Arguments,
+ const char * const *envp)
+ : InferiorProcess(M) {
+
+ // Start the child running...
+ startChild(M, Arguments, envp);
+
+ // Okay, we created the program and it is off and running. Wait for it to
+ // stop now.
+ try {
+ waitForStop();
+ } catch (InferiorProcessDead &IPD) {
+ throw "Error waiting for the child process to stop. "
+ "It exited with status " + itostr(IPD.getExitCode());
+ }
+}
+
+IP::~IP() {
+ // If the child is still running, kill it.
+ if (!ChildPID) return;
+
+ killChild();
+}
+
+/// getStatus - Return information about the unix process being debugged.
+///
+std::string IP::getStatus() const {
+ if (ChildPID == 0)
+ return "Unix target. ERROR: child process appears to be dead!\n";
+
+ return "Unix target: PID #" + utostr((unsigned)ChildPID) + "\n";
+}
+
+
+/// startChild - This starts up the child process, and initializes the
+/// ChildPID member.
+///
+void IP::startChild(Module *M, const std::vector<std::string> &Arguments,
+ const char * const *envp) {
+ // Create the pipes. Make sure to immediately assign the returned file
+ // descriptors to FDHandle's so they get destroyed if an exception is thrown.
+ int FDs[2];
+ if (pipe(FDs)) throw "Error creating a pipe!";
+ FDHandle ChildReadFD(FDs[0]);
+ WriteFD = FDs[1];
+
+ if (pipe(FDs)) throw "Error creating a pipe!";
+ ReadFD = FDs[0];
+ FDHandle ChildWriteFD(FDs[1]);
+
+ // Fork off the child process.
+ switch (ChildPID = fork()) {
+ case -1: throw "Error forking child process!";
+ case 0: // child
+ delete this; // Free parent pipe file descriptors
+ runChild(M, Arguments, envp, ChildReadFD, ChildWriteFD);
+ exit(1);
+ default: break;
+ }
+}
+
+/// sendCommand - Send a command token and the request data to the child.
+///
+void IP::sendCommand(CommandID Command, void *Data, unsigned Size) const {
+ writeToChild(&Command, sizeof(Command));
+ writeToChild(Data, Size);
+}
+
+/// stepProgram - Implement the 'step' command, continuing execution until
+/// the next possible stop point.
+void IP::stepProgram() {
+ sendCommand(StepProgram, 0, 0);
+ waitForStop();
+}
+
+/// finishProgram - Implement the 'finish' command, executing the program until
+/// the current function returns to its caller.
+void IP::finishProgram(void *Frame) {
+ sendCommand(FinishProgram, &Frame, sizeof(Frame));
+ waitForStop();
+}
+
+/// contProgram - Implement the 'cont' command, continuing execution until
+/// a breakpoint is encountered.
+void IP::contProgram() {
+ sendCommand(ContProgram, 0, 0);
+ waitForStop();
+}
+
+
+//===----------------------------------------------------------------------===//
+// Stack manipulation methods
+//
+
+/// getPreviousFrame - Given the descriptor for the current stack frame,
+/// return the descriptor for the caller frame. This returns null when it
+/// runs out of frames.
+void *IP::getPreviousFrame(void *Frame) const {
+ sendCommand(GetParentFrame, &Frame, sizeof(Frame));
+ readFromChild(&Frame, sizeof(Frame));
+ return Frame;
+}
+
+/// getSubprogramDesc - Return the subprogram descriptor for the current
+/// stack frame.
+const GlobalVariable *IP::getSubprogramDesc(void *Frame) const {
+ sendCommand(GetSubprogramDescriptor, &Frame, sizeof(Frame));
+ const GlobalVariable *Desc;
+ readFromChild(&Desc, sizeof(Desc));
+ return Desc;
+}
+
+/// getFrameLocation - This method returns the source location where each stack
+/// frame is stopped.
+void IP::getFrameLocation(void *Frame, unsigned &LineNo, unsigned &ColNo,
+ const GlobalVariable *&SourceDesc) const {
+ sendCommand(GetFrameLocation, &Frame, sizeof(Frame));
+ LocationToken Loc;
+ readFromChild(&Loc, sizeof(Loc));
+ LineNo = Loc.Line;
+ ColNo = Loc.Col;
+ SourceDesc = Loc.File;
+}
+
+
+//===----------------------------------------------------------------------===//
+// Breakpoint manipulation methods
+//
+unsigned IP::addBreakpoint(unsigned LineNo, unsigned ColNo,
+ const GlobalVariable *SourceDesc) {
+ LocationToken Loc;
+ Loc.Line = LineNo;
+ Loc.Col = ColNo;
+ Loc.File = SourceDesc;
+ sendCommand(AddBreakpoint, &Loc, sizeof(Loc));
+ unsigned ID;
+ readFromChild(&ID, sizeof(ID));
+ return ID;
+}
+
+void IP::removeBreakpoint(unsigned ID) {
+ sendCommand(RemoveBreakpoint, &ID, sizeof(ID));
+}
+
+
+//===----------------------------------------------------------------------===//
+// Methods for communication with the child process
+//
+// Methods for communicating with the child process. If the child exits or dies
+// while attempting to communicate with it, ChildPID is set to zero and an
+// exception is thrown.
+//
+
+/// readFromChild - Low-level primitive to read some data from the child,
+/// throwing an exception if it dies.
+void IP::readFromChild(void *Buffer, unsigned Size) const {
+ assert(ChildPID &&
+ "Child process died and still attempting to communicate with it!");
+ while (Size) {
+ ssize_t Amount = read(ReadFD, Buffer, Size);
+ if (Amount == 0) {
+ // If we cannot communicate with the process, kill it.
+ killChild();
+ // If killChild succeeded, then the process must have closed the pipe FD
+ // or something, because the child existed, but we cannot communicate with
+ // it.
+ throw InferiorProcessDead(-1);
+ } else if (Amount == -1) {
+ if (errno != EINTR) {
+ ChildPID = 0;
+ killChild();
+ throw "Error reading from child process!";
+ }
+ } else {
+ // We read a chunk.
+ Buffer = (char*)Buffer + Amount;
+ Size -= Amount;
+ }
+ }
+}
+
+/// writeToChild - Low-level primitive to send some data to the child
+/// process, throwing an exception if the child died.
+void IP::writeToChild(void *Buffer, unsigned Size) const {
+ while (Size) {
+ ssize_t Amount = write(WriteFD, Buffer, Size);
+ if (Amount < 0 && errno == EINTR) continue;
+ if (Amount <= 0) {
+ // If we cannot communicate with the process, kill it.
+ killChild();
+
+ // If killChild succeeded, then the process must have closed the pipe FD
+ // or something, because the child existed, but we cannot communicate with
+ // it.
+ throw InferiorProcessDead(-1);
+ } else {
+ // We wrote a chunk.
+ Buffer = (char*)Buffer + Amount;
+ Size -= Amount;
+ }
+ }
+}
+
+/// killChild - Kill or reap the child process. This throws the
+/// InferiorProcessDead exception an exit code if the process had already
+/// died, otherwise it just returns the exit code if it had to be killed.
+void IP::killChild() const {
+ assert(ChildPID != 0 && "Child has already been reaped!");
+
+ int Status = 0;
+ int PID;
+ do {
+ PID = waitpid(ChildPID, &Status, WNOHANG);
+ } while (PID < 0 && errno == EINTR);
+ if (PID < 0) throw "Error waiting for child to exit!";
+
+ // If the child process was already dead, then it died unexpectedly.
+ if (PID) {
+ assert(PID == ChildPID && "Didn't reap child?");
+ ChildPID = 0; // Child has been reaped
+ if (WIFEXITED(Status))
+ throw InferiorProcessDead(WEXITSTATUS(Status));
+ else if (WIFSIGNALED(Status))
+ throw InferiorProcessDead(WTERMSIG(Status));
+ throw InferiorProcessDead(-1);
+ }
+
+ // Otherwise, the child exists and has not yet been killed.
+ if (kill(ChildPID, SIGKILL) < 0)
+ throw "Error killing child process!";
+
+ do {
+ PID = waitpid(ChildPID, 0, 0);
+ } while (PID < 0 && errno == EINTR);
+ if (PID <= 0) throw "Error waiting for child to exit!";
+
+ assert(PID == ChildPID && "Didn't reap child?");
+}
+
+
+/// waitForStop - This method waits for the child process to reach a stop
+/// point. When it does, it fills in the CurLocation member and returns.
+void IP::waitForStop() {
+ char Dummy;
+ readFromChild(&Dummy, sizeof(char));
+}
+
+
+//===----------------------------------------------------------------------===//
+// Child Process Code
+//===----------------------------------------------------------------------===//
+
+namespace {
+ class SourceSubprogram;
+
+ /// SourceRegion - Instances of this class represent the regions that are
+ /// active in the program.
+ class SourceRegion {
+ /// Parent - A pointer to the region that encloses the current one.
+ SourceRegion *Parent;
+
+ /// CurSubprogram - The subprogram that contains this region. This allows
+ /// efficient stack traversals.
+ SourceSubprogram *CurSubprogram;
+
+ /// CurLine, CurCol, CurFile - The last location visited by this region.
+ /// This is used for getting the source location of callers in stack frames.
+ unsigned CurLine, CurCol;
+ void *CurFileDesc;
+
+ //std::vector<void*> ActiveObjects;
+ public:
+ SourceRegion(SourceRegion *p, SourceSubprogram *Subprogram = 0)
+ : Parent(p), CurSubprogram(Subprogram ? Subprogram : p->getSubprogram()) {
+ CurLine = 0; CurCol = 0;
+ CurFileDesc = 0;
+ }
+
+ virtual ~SourceRegion() {}
+
+ SourceRegion *getParent() const { return Parent; }
+ SourceSubprogram *getSubprogram() const { return CurSubprogram; }
+
+ void updateLocation(unsigned Line, unsigned Col, void *File) {
+ CurLine = Line;
+ CurCol = Col;
+ CurFileDesc = File;
+ }
+
+ /// Return a LocationToken for the place that this stack frame stopped or
+ /// called a sub-function.
+ LocationToken getLocation(ExecutionEngine *EE) {
+ LocationToken LT;
+ LT.Line = CurLine;
+ LT.Col = CurCol;
+ const GlobalValue *GV = EE->getGlobalValueAtAddress(CurFileDesc);
+ LT.File = dyn_cast_or_null<GlobalVariable>(GV);
+ return LT;
+ }
+ };
+
+ /// SourceSubprogram - This is a stack-frame that represents a source program.
+ ///
+ class SourceSubprogram : public SourceRegion {
+ /// Desc - A pointer to the descriptor for the subprogram that this frame
+ /// represents.
+ void *Desc;
+ public:
+ SourceSubprogram(SourceRegion *P, void *desc)
+ : SourceRegion(P, this), Desc(desc) {}
+ void *getDescriptor() const { return Desc; }
+ };
+
+
+ /// Child class - This class contains all of the information and methods used
+ /// by the child side of the debugger. The single instance of this object is
+ /// pointed to by the "TheChild" global variable.
+ class Child {
+ /// M - The module for the program currently being debugged.
+ ///
+ Module *M;
+
+ /// EE - The execution engine that we are using to run the program.
+ ///
+ ExecutionEngine *EE;
+
+ /// ReadFD, WriteFD - The file descriptor handles for this side of the
+ /// debugger pipe.
+ FDHandle ReadFD, WriteFD;
+
+ /// RegionStack - A linked list of all of the regions dynamically active.
+ ///
+ SourceRegion *RegionStack;
+
+ /// StopAtNextOpportunity - If this flag is set, the child process will stop
+ /// and report to the debugger at the next possible chance it gets.
+ volatile bool StopAtNextOpportunity;
+
+ /// StopWhenSubprogramReturns - If this is non-null, the debugger requests
+ /// that the program stops when the specified function frame is destroyed.
+ SourceSubprogram *StopWhenSubprogramReturns;
+
+ /// Breakpoints - This contains a list of active breakpoints and their IDs.
+ ///
+ std::vector<std::pair<unsigned, LocationToken> > Breakpoints;
+
+ /// CurBreakpoint - The last assigned breakpoint.
+ ///
+ unsigned CurBreakpoint;
+
+ public:
+ Child(Module *m, ExecutionEngine *ee, FDHandle &Read, FDHandle &Write)
+ : M(m), EE(ee), ReadFD(Read), WriteFD(Write),
+ RegionStack(0), CurBreakpoint(0) {
+ StopAtNextOpportunity = true;
+ StopWhenSubprogramReturns = 0;
+ }
+
+ /// writeToParent - Send the specified buffer of data to the debugger
+ /// process.
+ void writeToParent(const void *Buffer, unsigned Size);
+
+ /// readFromParent - Read the specified number of bytes from the parent.
+ ///
+ void readFromParent(void *Buffer, unsigned Size);
+
+ /// childStopped - This method is called whenever the child has stopped
+ /// execution due to a breakpoint, step command, interruption, or whatever.
+ /// This stops the process, responds to any requests from the debugger, and
+ /// when commanded to, can continue execution by returning.
+ ///
+ void childStopped();
+
+ /// startSubprogram - This method creates a new region for the subroutine
+ /// with the specified descriptor.
+ void startSubprogram(void *FuncDesc);
+
+ /// startRegion - This method initiates the creation of an anonymous region.
+ ///
+ void startRegion();
+
+ /// endRegion - This method terminates the last active region.
+ ///
+ void endRegion();
+
+ /// reachedLine - This method is automatically called by the program every
+ /// time it executes an llvm.dbg.stoppoint intrinsic. If the debugger wants
+ /// us to stop here, we do so, otherwise we continue execution.
+ void reachedLine(unsigned Line, unsigned Col, void *SourceDesc);
+ };
+
+ /// TheChild - The single instance of the Child class, which only gets created
+ /// in the child process.
+ Child *TheChild = 0;
+} // end anonymous namespace
+
+
+// writeToParent - Send the specified buffer of data to the debugger process.
+void Child::writeToParent(const void *Buffer, unsigned Size) {
+ while (Size) {
+ ssize_t Amount = write(WriteFD, Buffer, Size);
+ if (Amount < 0 && errno == EINTR) continue;
+ if (Amount <= 0) {
+ write(2, "ERROR: Connection to debugger lost!\n", 36);
+ abort();
+ } else {
+ // We wrote a chunk.
+ Buffer = (const char*)Buffer + Amount;
+ Size -= Amount;
+ }
+ }
+}
+
+// readFromParent - Read the specified number of bytes from the parent.
+void Child::readFromParent(void *Buffer, unsigned Size) {
+ while (Size) {
+ ssize_t Amount = read(ReadFD, Buffer, Size);
+ if (Amount < 0 && errno == EINTR) continue;
+ if (Amount <= 0) {
+ write(2, "ERROR: Connection to debugger lost!\n", 36);
+ abort();
+ } else {
+ // We read a chunk.
+ Buffer = (char*)Buffer + Amount;
+ Size -= Amount;
+ }
+ }
+}
+
+/// childStopped - This method is called whenever the child has stopped
+/// execution due to a breakpoint, step command, interruption, or whatever.
+/// This stops the process, responds to any requests from the debugger, and when
+/// commanded to, can continue execution by returning.
+///
+void Child::childStopped() {
+ // Since we stopped, notify the parent that we did so.
+ char Token = 0;
+ writeToParent(&Token, sizeof(char));
+
+ StopAtNextOpportunity = false;
+ StopWhenSubprogramReturns = 0;
+
+ // Now that the debugger knows that we stopped, read commands from it and
+ // respond to them appropriately.
+ CommandID Command;
+ while (1) {
+ SourceRegion *Frame;
+ const void *Result;
+ readFromParent(&Command, sizeof(CommandID));
+
+ switch (Command) {
+ case StepProgram:
+ // To step the program, just return.
+ StopAtNextOpportunity = true;
+ return;
+
+ case FinishProgram: // Run until exit from the specified function...
+ readFromParent(&Frame, sizeof(Frame));
+ // The user wants us to stop when the specified FUNCTION exits, not when
+ // the specified REGION exits.
+ StopWhenSubprogramReturns = Frame->getSubprogram();
+ return;
+
+ case ContProgram:
+ // To continue, just return back to execution.
+ return;
+
+ case GetSubprogramDescriptor:
+ readFromParent(&Frame, sizeof(Frame));
+ Result =
+ EE->getGlobalValueAtAddress(Frame->getSubprogram()->getDescriptor());
+ writeToParent(&Result, sizeof(Result));
+ break;
+
+ case GetParentFrame:
+ readFromParent(&Frame, sizeof(Frame));
+ Result = Frame ? Frame->getSubprogram()->getParent() : RegionStack;
+ writeToParent(&Result, sizeof(Result));
+ break;
+
+ case GetFrameLocation: {
+ readFromParent(&Frame, sizeof(Frame));
+ LocationToken LT = Frame->getLocation(EE);
+ writeToParent(<, sizeof(LT));
+ break;
+ }
+ case AddBreakpoint: {
+ LocationToken Loc;
+ readFromParent(&Loc, sizeof(Loc));
+ // Convert the GlobalVariable pointer to the address it was emitted to.
+ Loc.File = (GlobalVariable*)EE->getPointerToGlobal(Loc.File);
+ unsigned ID = CurBreakpoint++;
+ Breakpoints.push_back(std::make_pair(ID, Loc));
+ writeToParent(&ID, sizeof(ID));
+ break;
+ }
+ case RemoveBreakpoint: {
+ unsigned ID = 0;
+ readFromParent(&ID, sizeof(ID));
+ for (unsigned i = 0, e = Breakpoints.size(); i != e; ++i)
+ if (Breakpoints[i].first == ID) {
+ Breakpoints.erase(Breakpoints.begin()+i);
+ break;
+ }
+ break;
+ }
+ default:
+ assert(0 && "Unknown command!");
+ }
+ }
+}
+
+
+
+/// startSubprogram - This method creates a new region for the subroutine
+/// with the specified descriptor.
+void Child::startSubprogram(void *SPDesc) {
+ RegionStack = new SourceSubprogram(RegionStack, SPDesc);
+}
+
+/// startRegion - This method initiates the creation of an anonymous region.
+///
+void Child::startRegion() {
+ RegionStack = new SourceRegion(RegionStack);
+}
+
+/// endRegion - This method terminates the last active region.
+///
+void Child::endRegion() {
+ SourceRegion *R = RegionStack->getParent();
+
+ // If the debugger wants us to stop when this frame is destroyed, do so.
+ if (RegionStack == StopWhenSubprogramReturns) {
+ StopAtNextOpportunity = true;
+ StopWhenSubprogramReturns = 0;
+ }
+
+ delete RegionStack;
+ RegionStack = R;
+}
+
+
+
+
+/// reachedLine - This method is automatically called by the program every time
+/// it executes an llvm.dbg.stoppoint intrinsic. If the debugger wants us to
+/// stop here, we do so, otherwise we continue execution. Note that the Data
+/// pointer coming in is a pointer to the LLVM global variable that represents
+/// the source file we are in. We do not use the contents of the global
+/// directly in the child, but we do use its address.
+///
+void Child::reachedLine(unsigned Line, unsigned Col, void *SourceDesc) {
+ if (RegionStack)
+ RegionStack->updateLocation(Line, Col, SourceDesc);
+
+ // If we hit a breakpoint, stop the program.
+ for (unsigned i = 0, e = Breakpoints.size(); i != e; ++i)
+ if (Line == Breakpoints[i].second.Line &&
+ SourceDesc == (void*)Breakpoints[i].second.File &&
+ Col == Breakpoints[i].second.Col) {
+ childStopped();
+ return;
+ }
+
+ // If we are single stepping the program, make sure to stop it.
+ if (StopAtNextOpportunity)
+ childStopped();
+}
+
+
+
+
+//===----------------------------------------------------------------------===//
+// Child class wrapper functions
+//
+// These functions are invoked directly by the program as it executes, in place
+// of the debugging intrinsic functions that it contains.
+//
+
+
+/// llvm_debugger_stop - Every time the program reaches a new source line, it
+/// will call back to this function. If the debugger has a breakpoint or
+/// otherwise wants us to stop on this line, we do so, and notify the debugger
+/// over the pipe.
+///
+extern "C"
+void *llvm_debugger_stop(void *Dummy, unsigned Line, unsigned Col,
+ void *SourceDescriptor) {
+ TheChild->reachedLine(Line, Col, SourceDescriptor);
+ return Dummy;
+}
+
+
+/// llvm_dbg_region_start - This function is invoked every time an anonymous
+/// region of the source program is entered.
+///
+extern "C"
+void *llvm_dbg_region_start(void *Dummy) {
+ TheChild->startRegion();
+ return Dummy;
+}
+
+/// llvm_dbg_subprogram - This function is invoked every time a source-language
+/// subprogram has been entered.
+///
+extern "C"
+void *llvm_dbg_subprogram(void *FuncDesc) {
+ TheChild->startSubprogram(FuncDesc);
+ return 0;
+}
+
+/// llvm_dbg_region_end - This function is invoked every time a source-language
+/// region (started with llvm.dbg.region.start or llvm.dbg.func.start) is
+/// terminated.
+///
+extern "C"
+void llvm_dbg_region_end(void *Dummy) {
+ TheChild->endRegion();
+}
+
+
+
+
+namespace {
+ /// DebuggerIntrinsicLowering - This class implements a simple intrinsic
+ /// lowering class that revectors debugging intrinsics to call actual
+ /// functions (defined above), instead of being turned into noops.
+ struct DebuggerIntrinsicLowering : public DefaultIntrinsicLowering {
+ virtual void LowerIntrinsicCall(CallInst *CI) {
+ Module *M = CI->getParent()->getParent()->getParent();
+ switch (CI->getCalledFunction()->getIntrinsicID()) {
+ case Intrinsic::dbg_stoppoint:
+ // Turn call into a call to llvm_debugger_stop
+ CI->setOperand(0, M->getOrInsertFunction("llvm_debugger_stop",
+ CI->getCalledFunction()->getFunctionType()));
+ break;
+ case Intrinsic::dbg_region_start:
+ // Turn call into a call to llvm_dbg_region_start
+ CI->setOperand(0, M->getOrInsertFunction("llvm_dbg_region_start",
+ CI->getCalledFunction()->getFunctionType()));
+ break;
+
+ case Intrinsic::dbg_region_end:
+ // Turn call into a call to llvm_debugger_stop
+ CI->setOperand(0, M->getOrInsertFunction("llvm_dbg_region_end",
+ CI->getCalledFunction()->getFunctionType()));
+ break;
+ case Intrinsic::dbg_func_start:
+ // Turn call into a call to llvm_debugger_stop
+ CI->setOperand(0, M->getOrInsertFunction("llvm_dbg_subprogram",
+ CI->getCalledFunction()->getFunctionType()));
+ break;
+ default:
+ DefaultIntrinsicLowering::LowerIntrinsicCall(CI);
+ break;
+ }
+ }
+ };
+} // end anonymous namespace
+
+
+static void runChild(Module *M, const std::vector<std::string> &Arguments,
+ const char * const *envp,
+ FDHandle ReadFD, FDHandle WriteFD) {
+
+ // Create an execution engine that uses our custom intrinsic lowering object
+ // to revector debugging intrinsic functions into actual functions defined
+ // above.
+ ExecutionEngine *EE =
+ ExecutionEngine::create(new ExistingModuleProvider(M), false,
+ new DebuggerIntrinsicLowering());
+ assert(EE && "Couldn't create an ExecutionEngine, not even an interpreter?");
+
+ // Call the main function from M as if its signature were:
+ // int main (int argc, char **argv, const char **envp)
+ // using the contents of Args to determine argc & argv, and the contents of
+ // EnvVars to determine envp.
+ //
+ Function *Fn = M->getMainFunction();
+ if (!Fn) exit(1);
+
+ // Create the child class instance which will be used by the debugger
+ // callbacks to keep track of the current state of the process.
+ assert(TheChild == 0 && "A child process has already been created??");
+ TheChild = new Child(M, EE, ReadFD, WriteFD);
+
+ // Run main...
+ int Result = EE->runFunctionAsMain(Fn, Arguments, envp);
+
+ // If the program didn't explicitly call exit, call exit now, for the program.
+ // This ensures that any atexit handlers get called correctly.
+ Function *Exit = M->getOrInsertFunction("exit", Type::VoidTy, Type::IntTy, 0);
+
+ std::vector<GenericValue> Args;
+ GenericValue ResultGV;
+ ResultGV.IntVal = Result;
+ Args.push_back(ResultGV);
+ EE->runFunction(Exit, Args);
+ abort();
+}