performace improvments

breakpoint.h

@@ -34,15 +34,20 @@
 #define HW_BP_SCRATCH	2
 
 struct breakpoint {
-	int (*on_hit)(struct task *task, struct breakpoint *bp);
-	struct library_symbol *libsym;
 	arch_addr_t addr;
+
 	unsigned int enabled:1;
 	unsigned int locked:1;
 	unsigned int deleted:1;
 	unsigned int type:2;
 	unsigned int ext:8;
+
 	unsigned int refcnt;
+
+	int (*on_hit)(struct task *task, struct breakpoint *bp);
+
+	struct library_symbol *libsym;
+
 	union {
 		unsigned char orig_value[BREAKPOINT_LENGTH];
 #if HW_BREAKPOINTS > 0

dwarf.c

@@ -403,7 +403,7 @@ static inline int dwarf_readw(struct dwarf_addr_space *as, arch_addr_t *addr, ar
 	int ret;
 
 	if (is_64bit) {
-		uint64_t u64;
+		uint64_t u64 = 0;
 
 		ret = dwarf_read64(as, addr, &u64);
 
@@ -411,7 +411,7 @@ static inline int dwarf_readw(struct dwarf_addr_space *as, arch_addr_t *addr, ar
 			*valp = u64;
 	}
 	else {
-		uint32_t u32;
+		uint32_t u32 = 0;
 
 		ret = dwarf_read32(as, addr, &u32);
 

sysdeps/linux-gnu/x86/arch.c

@@ -70,6 +70,9 @@ static int set_breakpoint_addr(struct task *task, arch_addr_t addr, unsigned int
 		addr &= 0xffffffff;
 #endif
 
+	if (task->arch.hw_bp[n] == addr)
+		return 0;
+
 	ret = ptrace(PTRACE_POKEUSER, task->pid, offsetof(struct user, u_debugreg[n]), addr);
 	if (ret) {
 		if (errno != ESRCH) {
@@ -77,6 +80,9 @@ static int set_breakpoint_addr(struct task *task, arch_addr_t addr, unsigned int
 			return -1;
 		}
 	}
+
+	task->arch.hw_bp[n] = addr;
+
 	return 0;
 }
 
@@ -187,6 +193,11 @@ int is_64bit(struct mt_elf *mte)
 
 int arch_task_init(struct task *task)
 {
+	unsigned int i;
+
+	for(i = 0; i < HW_BREAKPOINTS; ++i)
+		task->arch.hw_bp[i] = 0;
+
 	return _apply_hw_bp(task, 0);
 }
 

sysdeps/linux-gnu/x86/arch.h

@@ -52,6 +52,7 @@ struct context {
 
 struct arch_task_data {
 	unsigned long dr7;
+	unsigned long hw_bp[HW_BREAKPOINTS];
 };
 
 #endif

task.h

@@ -38,10 +38,18 @@
 #include "report.h"
 
 struct task {
-	struct rb_node pid_node;	/* red/black tree node for fast pid -> struct task */
+	/* red/black tree node for fast pid -> struct task */
+	struct rb_node pid_node;
 
+	/* process id */
 	pid_t pid;
 
+	/* points to the leader thread of the POSIX.1 task */
+	struct task *leader;
+
+	/* current pendig event */
+	struct event event;
+
 	unsigned int stopped:1;
 	unsigned int traced:1;
 	unsigned int was_stopped:1;
@@ -49,42 +57,10 @@ struct task {
 	unsigned int attached:1;
 	unsigned int deleted:1;
 
-	/* Dictionary of breakpoints */
+	struct breakpoint *breakpoint;
-	struct dict *breakpoints;
-
 	struct library_symbol *libsym;
 	struct context context;		/* process context (registers, stack) */
 	struct context saved_context;	/* context for fetch_param() */
-	struct breakpoint *breakpoint;
-
-	unsigned int threads;		/* set in leader: number of threads including the leader */
-	unsigned int threads_stopped;	/* set in leader: number of stopped threads including the leader */
-
-	/* linked list of libraries, the first entry is the executable itself */
-	struct list_head libraries_list;
-
-	void *backtrace;
-
-	/* struct task chaining. */
-	struct list_head leader_list;
-
-	/* points to the leader thread of the POSIX.1 task */
-	struct task *leader;
-
-	/* Thread chaining to leader */
-	struct list_head task_list;
-
-	/* current pendig event */
-	struct event event;
-
-	/* pointer to a breakpoint which was interrupt by a signal during skip */
-	struct breakpoint *skip_bp;
-
-	/* only used in leader: bit mask for used hw breakpoints */
-	unsigned long hw_bp_mask;
-
-	/* array of addresses of hw breakpoints */
-	struct breakpoint *hw_bp[HW_BREAKPOINTS];
 
 	/* os specific task data */
 #ifdef OS_HAVE_PROCESS_DATA
@@ -95,6 +71,36 @@ struct task {
 #ifdef TASK_HAVE_PROCESS_DATA
 	struct arch_task_data arch;
 #endif
+
+	/* pointer to a breakpoint which was interrupt by a signal during skip */
+	struct breakpoint *skip_bp;
+
+	/* array of addresses of hw breakpoints */
+	struct breakpoint *hw_bp[HW_BREAKPOINTS];
+
+	/* set in leader: number of stopped threads including the leader */
+	unsigned int threads_stopped;
+
+	/* set in leader: dictionary of breakpoints */
+	struct dict *breakpoints;
+
+	/* set in leader: backtrace pimpl */
+	void *backtrace;
+
+	/* linked list of libraries, the first entry is the executable itself */
+	struct list_head libraries_list;
+
+	/* Thread chaining to leader */
+	struct list_head task_list;
+
+	/* set in leader: number of threads including the leader */
+	unsigned int threads;
+
+	/* only used in leader: bit mask for used hw breakpoints */
+	unsigned long hw_bp_mask;
+
+	/* struct task chaining. */
+	struct list_head leader_list;
 };
 
 /* PROC underwent an exec.  This is a bit like task_destroy