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Add memory watchpoint support for source debugger (#1762)

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Allow to add watchpoints to variables for source debugging. For instance:
`breakpoint set variable var`
will pause WAMR execution when the address at var is written to.
Can also set read/write watchpoints by passing r/w flags. This will pause
execution when the address at var is read:
`watchpoint set variable -w read var`

Add two linked lists for read/write watchpoints. When the debug message
handler receives a watchpoint request, it adds/removes to one/both of these
lists. In the interpreter, when an address is read or stored to, check whether
the address is in these lists. If so, throw a sigtrap and suspend the process.
This commit is contained in:
Callum Macmillan
2022-12-07 09:18:28 +00:00
committed by GitHub
parent 9d52960e4d
commit c3d66f916e
4 changed files with 265 additions and 25 deletions
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82
core/iwasm/libraries/debug-engine/debug_engine.c
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@ -392,6 +392,8 @@ wasm_debug_instance_create(WASMCluster *cluster, int32 port)
}
bh_list_init(&instance->break_point_list);
bh_list_init(&instance->watch_point_list_read);
bh_list_init(&instance->watch_point_list_write);
instance->cluster = cluster;
exec_env = bh_list_first_elem(&cluster->exec_env_list);
@ -452,6 +454,23 @@ wasm_debug_instance_destroy_breakpoints(WASMDebugInstance *instance)
}
}
static void
wasm_debug_instance_destroy_watchpoints(WASMDebugInstance *instance,
bh_list *watchpoints)
{
WASMDebugWatchPoint *watchpoint, *next;
watchpoint = bh_list_first_elem(watchpoints);
while (watchpoint) {
next = bh_list_elem_next(watchpoint);
bh_list_remove(watchpoints, watchpoint);
wasm_runtime_free(watchpoint);
watchpoint = next;
}
}
void
wasm_debug_instance_destroy(WASMCluster *cluster)
{
@ -472,6 +491,10 @@ wasm_debug_instance_destroy(WASMCluster *cluster)
/* destroy all breakpoints */
wasm_debug_instance_destroy_breakpoints(instance);
wasm_debug_instance_destroy_watchpoints(
instance, &instance->watch_point_list_read);
wasm_debug_instance_destroy_watchpoints(
instance, &instance->watch_point_list_write);
os_mutex_destroy(&instance->wait_lock);
os_cond_destroy(&instance->wait_cond);
@ -995,6 +1018,65 @@ wasm_debug_instance_remove_breakpoint(WASMDebugInstance *instance, uint64 addr,
return true;
}
static bool
add_watchpoint(bh_list *list, uint64 addr, uint64 length)
{
WASMDebugWatchPoint *watchpoint;
if (!(watchpoint = wasm_runtime_malloc(sizeof(WASMDebugWatchPoint)))) {
LOG_ERROR("WASM Debug Engine error: failed to allocate memory for "
"watchpoint");
return false;
}
memset(watchpoint, 0, sizeof(WASMDebugWatchPoint));
watchpoint->addr = addr;
watchpoint->length = length;
bh_list_insert(list, watchpoint);
return true;
}
static bool
remove_watchpoint(bh_list *list, uint64 addr, uint64 length)
{
WASMDebugWatchPoint *watchpoint = bh_list_first_elem(list);
while (watchpoint) {
WASMDebugWatchPoint *next = bh_list_elem_next(watchpoint);
if (watchpoint->addr == addr && watchpoint->length == length) {
bh_list_remove(list, watchpoint);
wasm_runtime_free(watchpoint);
}
watchpoint = next;
}
return true;
}
bool
wasm_debug_instance_watchpoint_write_add(WASMDebugInstance *instance,
uint64 addr, uint64 length)
{
return add_watchpoint(&instance->watch_point_list_write, addr, length);
}
bool
wasm_debug_instance_watchpoint_write_remove(WASMDebugInstance *instance,
uint64 addr, uint64 length)
{
return remove_watchpoint(&instance->watch_point_list_write, addr, length);
}
bool
wasm_debug_instance_watchpoint_read_add(WASMDebugInstance *instance,
uint64 addr, uint64 length)
{
return add_watchpoint(&instance->watch_point_list_read, addr, length);
}
bool
wasm_debug_instance_watchpoint_read_remove(WASMDebugInstance *instance,
uint64 addr, uint64 length)
{
return remove_watchpoint(&instance->watch_point_list_read, addr, length);
}
bool
wasm_debug_instance_on_failure(WASMDebugInstance *instance)
{