Debugger: Add software breakpoints, fix cleanup

CHANGES

@@ -92,6 +92,7 @@ Misc:
  - 3DS: 3D banner
  - FFmpeg: Full support for libavcodec 56+
  - Util: PNG utils should support 16-bit when applicable
+ - Debugger: Add software breakpoint support to gdb
 
 0.4.1: (2016-07-11)
 Bugfixes:

src/arm/debugger/debugger.c

@@ -1,4 +1,4 @@
-/* Copyright (c) 2013-2014 Jeffrey Pfau
+/* Copyright (c) 2013-2016 Jeffrey Pfau
  *
  * This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
@@ -37,7 +37,8 @@ static void ARMDebuggerCheckBreakpoints(struct mDebuggerPlatform* d) {
 		return;
 	}
 	struct mDebuggerEntryInfo info = {
-		.address = breakpoint->address
+		.address = breakpoint->address,
+		.breakType = BREAKPOINT_HARDWARE
 	};
 	mDebuggerEnter(d->p, DEBUGGER_ENTER_BREAKPOINT, &info);
 }
@@ -79,6 +80,16 @@ void ARMDebuggerInit(void* cpu, struct mDebuggerPlatform* platform) {
 
 void ARMDebuggerDeinit(struct mDebuggerPlatform* platform) {
 	struct ARMDebugger* debugger = (struct ARMDebugger*) platform;
+	if (debugger->clearSoftwareBreakpoint) {
+		// Clear the stack backwards in case any overlap
+		size_t b;
+		for (b = ARMDebugBreakpointListSize(&debugger->swBreakpoints); b; --b) {
+			struct ARMDebugBreakpoint* breakpoint = ARMDebugBreakpointListGetPointer(&debugger->swBreakpoints, b - 1);
+			debugger->clearSoftwareBreakpoint(debugger, breakpoint->address, breakpoint->sw.mode, breakpoint->sw.opcode);
+		}
+	}
+	ARMDebuggerRemoveMemoryShim(debugger);
+
 	ARMDebugBreakpointListDeinit(&debugger->breakpoints);
 	ARMDebugBreakpointListDeinit(&debugger->swBreakpoints);
 	ARMDebugWatchpointListDeinit(&debugger->watchpoints);
@@ -103,8 +114,8 @@ static void ARMDebuggerEnter(struct mDebuggerPlatform* platform, enum mDebuggerE
 			}
 		}
 	}
-	if (debugger->entered) {
-		debugger->entered(debugger->d.p, reason, info);
+	if (debugger->d.p->entered) {
+		debugger->d.p->entered(debugger->d.p, reason, info);
 	}
 }
 
@@ -124,6 +135,26 @@ bool ARMDebuggerSetSoftwareBreakpoint(struct mDebuggerPlatform* d, uint32_t addr
 	return true;
 }
 
+void ARMDebuggerClearSoftwareBreakpoint(struct mDebuggerPlatform* d, uint32_t address) {
+	struct ARMDebugger* debugger = (struct ARMDebugger*) d;
+	if (!debugger->clearSoftwareBreakpoint) {
+		return;
+	}
+
+	struct ARMDebugBreakpoint* breakpoint = NULL;
+	// Clear the stack backwards in case any overlap
+	size_t b;
+	for (b = ARMDebugBreakpointListSize(&debugger->swBreakpoints); b; --b) {
+		breakpoint = ARMDebugBreakpointListGetPointer(&debugger->swBreakpoints, b - 1);
+		if (breakpoint->address == address) {
+			break;
+		}
+		breakpoint = NULL;
+	}
+
+	debugger->clearSoftwareBreakpoint(debugger, address, breakpoint->sw.mode, breakpoint->sw.opcode);
+}
+
 static void ARMDebuggerSetBreakpoint(struct mDebuggerPlatform* d, uint32_t address) {
 	struct ARMDebugger* debugger = (struct ARMDebugger*) d;
 	struct ARMDebugBreakpoint* breakpoint = ARMDebugBreakpointListAppend(&debugger->breakpoints);

src/arm/debugger/debugger.h

@@ -39,3 +39,4 @@ struct ARMDebugger {
 
 struct mDebuggerPlatform* ARMDebuggerPlatformCreate(void);
 bool ARMDebuggerSetSoftwareBreakpoint(struct mDebuggerPlatform* debugger, uint32_t address, enum ExecutionMode mode);
+void ARMDebuggerClearSoftwareBreakpoint(struct mDebuggerPlatform* debugger, uint32_t address);

src/debugger/CMakeLists.txt

@@ -0,0 +1,22 @@
+set(SRC
+	debugger.c
+	parser.c
+	)
+
+set(RENDERER_SRC
+	renderers/software-bg.c
+	renderers/software-mode0.c
+	renderers/software-obj.c
+	renderers/video-software.c
+	)
+
+if(USE_CLI_DEBUGGER)
+	list(APPEND SRC cli-debugger.c)
+endif()
+
+if(USE_GDB_STUB)
+	list(APPEND SRC gdb-stub.c)
+endif()
+
+source_group("Debugger source" FILES ${SRC})
+add_internal_library(debugger "${SRC}" "")

src/debugger/debugger.c

@@ -102,8 +102,8 @@ void mDebuggerRun(struct mDebugger* debugger) {
 
 void mDebuggerEnter(struct mDebugger* debugger, enum mDebuggerEntryReason reason, struct mDebuggerEntryInfo* info) {
 	debugger->state = DEBUGGER_PAUSED;
-	if (debugger->entered) {
-		debugger->entered(debugger, reason, info);
+	if (debugger->platform->entered) {
+		debugger->platform->entered(debugger->platform, reason, info);
 	}
 }
 

src/debugger/debugger.h

@@ -40,6 +40,11 @@ enum mWatchpointType {
 	WATCHPOINT_RW = WATCHPOINT_WRITE | WATCHPOINT_READ
 };
 
+enum mBreakpointType {
+	BREAKPOINT_HARDWARE,
+	BREAKPOINT_SOFTWARE
+};
+
 enum mDebuggerEntryReason {
 	DEBUGGER_ENTER_MANUAL,
 	DEBUGGER_ENTER_ATTACHED,
@@ -48,6 +53,14 @@ enum mDebuggerEntryReason {
 	DEBUGGER_ENTER_ILLEGAL_OP
 };
 
+struct mDebugWatchpoint {
+	uint32_t address;
+	enum mWatchpointType type;
+};
+
+DECLARE_VECTOR(mDebugBreakpointList, struct mDebugBreakpoint);
+DECLARE_VECTOR(mDebugWatchpointList, struct mDebugWatchpoint);
+
 extern const char* ERROR_MISSING_ARGS;
 extern const char* ERROR_OVERFLOW;
 
@@ -63,6 +76,7 @@ struct mDebuggerEntryInfo {
 
 		struct {
 			uint32_t opcode;
+			enum mBreakpointType breakType;
 		};
 	};
 };

src/debugger/gdb-stub.c

@@ -1,10 +1,11 @@
-/* Copyright (c) 2013-2014 Jeffrey Pfau
+/* Copyright (c) 2013-2016 Jeffrey Pfau
  *
  * This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 #include "gdb-stub.h"
 
+#include "arm/debugger/debugger.h"
 #include "arm/isa-inlines.h"
 #include "core/core.h"
 #include "gba/memory.h"
@@ -44,7 +45,11 @@ static void _gdbStubEntered(struct mDebugger* debugger, enum mDebuggerEntryReaso
 		snprintf(stub->outgoing, GDB_STUB_MAX_LINE - 4, "S%02x", SIGINT);
 		break;
 	case DEBUGGER_ENTER_BREAKPOINT:
-		snprintf(stub->outgoing, GDB_STUB_MAX_LINE - 4, "S%02x", SIGTRAP); // TODO: Use hwbreak/swbreak if gdb supports it
+		if (stub->supportsHwbreak && stub->supportsSwbreak && info) {
+			snprintf(stub->outgoing, GDB_STUB_MAX_LINE - 4, "T%02x%cwbreak:;", SIGTRAP, info->breakType == BREAKPOINT_SOFTWARE ? 's' : 'h');
+		} else {
+			snprintf(stub->outgoing, GDB_STUB_MAX_LINE - 4, "S%02xk", SIGTRAP);
+		}
 		break;
 	case DEBUGGER_ENTER_WATCHPOINT:
 		if (info) {
@@ -385,6 +390,35 @@ static void _readRegister(struct GDBStub* stub, const char* message) {
 	_sendMessage(stub);
 }
 
+static void _processQSupportedCommand(struct GDBStub* stub, const char* message) {
+	const char* terminator = strrchr(message, '#');
+	stub->supportsSwbreak = false;
+	stub->supportsHwbreak = false;
+	while (message < terminator) {
+		const char* end = strchr(message, ';');
+		size_t len;
+		if (end && end < terminator) {
+			len = end - message;
+		} else {
+			len = end - terminator;
+		}
+		if (!strncmp(message, "swbreak+", 8)) {
+			stub->supportsSwbreak = true;
+		} else if (!strncmp(message, "hwbreak+", 8)) {
+			stub->supportsHwbreak = true;
+		} else if (!strncmp(message, "swbreak-", 8)) {
+			stub->supportsSwbreak = false;
+		} else if (!strncmp(message, "hwbreak-", 8)) {
+			stub->supportsHwbreak = false;
+		}
+		if (!end) {
+			break;
+		}
+		message = end + 1;
+	}
+	strncpy(stub->outgoing, "swbreak+;hwbreak+", GDB_STUB_MAX_LINE - 4);
+}
+
 static void _processQReadCommand(struct GDBStub* stub, const char* message) {
 	stub->outgoing[0] = '\0';
 	if (!strncmp("HostInfo#", message, 9)) {
@@ -401,6 +435,8 @@ static void _processQReadCommand(struct GDBStub* stub, const char* message) {
 		strncpy(stub->outgoing, "m1", GDB_STUB_MAX_LINE - 4);
 	} else if (!strncmp("sThreadInfo#", message, 12)) {
 		strncpy(stub->outgoing, "l", GDB_STUB_MAX_LINE - 4);
+	} else if (!strncmp("Supported:", message, 10)) {
+		_processQSupportedCommand(stub, message + 10);
 	}
 	_sendMessage(stub);
 }
@@ -434,36 +470,31 @@ static void _setBreakpoint(struct GDBStub* stub, const char* message) {
 	unsigned i = 0;
 	uint32_t address = _readHex(readAddress, &i);
 	readAddress += i + 1;
-	uint32_t kind = _readHex(readAddress, &i); // We don't use this in hardware watchpoints
-	UNUSED(kind);
+	uint32_t kind = _readHex(readAddress, &i);
 
 	switch (message[0]) {
-	case '0': // Memory breakpoints are not currently supported
+	case '0':
+		ARMDebuggerSetSoftwareBreakpoint(stub->d.platform, address, kind == 2 ? MODE_THUMB : MODE_ARM);
+		break;
 	case '1':
 		stub->d.platform->setBreakpoint(stub->d.platform, address);
-		strncpy(stub->outgoing, "OK", GDB_STUB_MAX_LINE - 4);
-		_sendMessage(stub);
 		break;
 	case '2':
 		stub->d.platform->setWatchpoint(stub->d.platform, address, WATCHPOINT_WRITE);
-		strncpy(stub->outgoing, "OK", GDB_STUB_MAX_LINE - 4);
-		_sendMessage(stub);
 		break;
 	case '3':
 		stub->d.platform->setWatchpoint(stub->d.platform, address, WATCHPOINT_READ);
-		strncpy(stub->outgoing, "OK", GDB_STUB_MAX_LINE - 4);
-		_sendMessage(stub);
 		break;
 	case '4':
 		stub->d.platform->setWatchpoint(stub->d.platform, address, WATCHPOINT_RW);
-		strncpy(stub->outgoing, "OK", GDB_STUB_MAX_LINE - 4);
-		_sendMessage(stub);
 		break;
 	default:
 		stub->outgoing[0] = '\0';
 		_sendMessage(stub);
-		break;
+		return;
 	}
+	strncpy(stub->outgoing, "OK", GDB_STUB_MAX_LINE - 4);
+	_sendMessage(stub);
 }
 
 static void _clearBreakpoint(struct GDBStub* stub, const char* message) {
@@ -471,7 +502,9 @@ static void _clearBreakpoint(struct GDBStub* stub, const char* message) {
 	unsigned i = 0;
 	uint32_t address = _readHex(readAddress, &i);
 	switch (message[0]) {
-	case '0': // Memory breakpoints are not currently supported
+	case '0':
+		ARMDebuggerClearSoftwareBreakpoint(stub->d.platform, address);
+		break;
 	case '1':
 		stub->d.platform->clearBreakpoint(stub->d.platform, address);
 		break;

src/debugger/gdb-stub.h

@@ -34,6 +34,9 @@ struct GDBStub {
 
 	bool shouldBlock;
 	int untilPoll;
+
+	bool supportsSwbreak;
+	bool supportsHwbreak;
 };
 
 void GDBStubCreate(struct GDBStub*);

src/gba/gba.c

@@ -799,7 +799,8 @@ void GBABreakpoint(struct ARMCore* cpu, int immediate) {
 	case CPU_COMPONENT_DEBUGGER:
 		if (gba->debugger) {
 			struct mDebuggerEntryInfo info = {
-				.address = _ARMPCAddress(cpu)
+				.address = _ARMPCAddress(cpu),
+				.breakType = BREAKPOINT_SOFTWARE
 			};
 			mDebuggerEnter(gba->debugger->d.p, DEBUGGER_ENTER_BREAKPOINT, &info);
 		}