[Lldb-commits] [lldb] 624813a - Change the dyld notification function that lldb puts a breakpoint in
Jason Molenda via lldb-commits
lldb-commits at lists.llvm.org
Fri Jun 30 18:29:54 PDT 2023
Author: Jason Molenda
Date: 2023-06-30T18:29:46-07:00
New Revision: 624813a4f41c5945dc8f8d998173960ad75db731
URL: https://github.com/llvm/llvm-project/commit/624813a4f41c5945dc8f8d998173960ad75db731
DIFF: https://github.com/llvm/llvm-project/commit/624813a4f41c5945dc8f8d998173960ad75db731.diff
LOG: Change the dyld notification function that lldb puts a breakpoint in
On Darwin systems, the dynamic linker dyld has an empty function
it calls when binaries are added/removed from the process. lldb puts
a breakpoint on this dyld function to catch the notifications. The
function arguments are used by lldb to tell what is happening.
The linker has a natural representation when the addresses of
binaries being added/removed are in the pointer size of the process.
There is then a second function where the addresses of the binaries
are in a uint64_t array, which the debugger has been using before -
dyld allocates memory for the array, copies the values in to it,
and calls it for lldb's benefit.
This changes to using the native notifier function, with pointer-sized
addresses.
Differential Revision: https://reviews.llvm.org/D139453
Added:
Modified:
lldb/source/Plugins/DynamicLoader/MacOSX-DYLD/DynamicLoaderMacOS.cpp
Removed:
################################################################################
diff --git a/lldb/source/Plugins/DynamicLoader/MacOSX-DYLD/DynamicLoaderMacOS.cpp b/lldb/source/Plugins/DynamicLoader/MacOSX-DYLD/DynamicLoaderMacOS.cpp
index 67e79fdcec8f56..f439fa88fc7345 100644
--- a/lldb/source/Plugins/DynamicLoader/MacOSX-DYLD/DynamicLoaderMacOS.cpp
+++ b/lldb/source/Plugins/DynamicLoader/MacOSX-DYLD/DynamicLoaderMacOS.cpp
@@ -235,10 +235,15 @@ bool DynamicLoaderMacOS::NotifyBreakpointHit(void *baton,
lldb::user_id_t break_loc_id) {
// Let the event know that the images have changed
// DYLD passes three arguments to the notification breakpoint.
- // Arg1: enum dyld_notify_mode mode - 0 = adding, 1 = removing, 2 = remove
- // all Arg2: unsigned long icount - Number of shared libraries
- // added/removed Arg3: uint64_t mach_headers[] - Array of load addresses
- // of binaries added/removed
+ //
+ // Arg1: enum dyld_notify_mode mode
+ // 0 = adding, 1 = removing, 2 = remove all, 3 = dyld moved
+ //
+ // Arg2: unsigned long count
+ // Number of shared libraries added/removed
+ //
+ // Arg3: struct dyld_image_info mach_headers[]
+ // Array of load addresses of binaries added/removed
DynamicLoaderMacOS *dyld_instance = (DynamicLoaderMacOS *)baton;
@@ -268,9 +273,10 @@ bool DynamicLoaderMacOS::NotifyBreakpointHit(void *baton,
ValueList argument_values;
Value mode_value; // enum dyld_notify_mode { dyld_notify_adding=0,
- // dyld_notify_removing=1, dyld_notify_remove_all=2 };
+ // dyld_notify_removing=1, dyld_notify_remove_all=2,
+ // dyld_notify_dyld_moved=3 };
Value count_value; // unsigned long count
- Value headers_value; // uint64_t machHeaders[] (aka void*)
+ Value headers_value; // struct dyld_image_info machHeaders[]
CompilerType clang_void_ptr_type =
scratch_ts_sp->GetBasicType(eBasicTypeVoid).GetPointerType();
@@ -299,6 +305,9 @@ bool DynamicLoaderMacOS::NotifyBreakpointHit(void *baton,
argument_values.PushValue(count_value);
argument_values.PushValue(headers_value);
+ // void lldb_image_notifier(enum dyld_image_mode mode, uint32_t infoCount,
+ // const dyld_image_info info[])
+
if (abi->GetArgumentValues(exe_ctx.GetThreadRef(), argument_values)) {
uint32_t dyld_mode =
argument_values.GetValueAtIndex(0)->GetScalar().UInt(-1);
@@ -312,12 +321,32 @@ bool DynamicLoaderMacOS::NotifyBreakpointHit(void *baton,
argument_values.GetValueAtIndex(2)->GetScalar().ULongLong(-1);
if (header_array != static_cast<uint64_t>(-1)) {
std::vector<addr_t> image_load_addresses;
+
+ // struct dyld_image_info_32 {
+ // uint32_t imageLoadAddress;
+ // uint32_t imageFilePath;
+ // uint32_t imageFileModDate;
+ // };
+ // struct dyld_image_info_64 {
+ // uint64_t imageLoadAddress;
+ // uint64_t imageFilePath;
+ // uint64_t imageFileModDate;
+ // };
+
+ uint32_t addr_size =
+ process->GetTarget().GetArchitecture().GetAddressByteSize();
for (uint64_t i = 0; i < image_infos_count; i++) {
Status error;
- addr_t addr = process->ReadUnsignedIntegerFromMemory(
- header_array + (8 * i), 8, LLDB_INVALID_ADDRESS, error);
- if (addr != LLDB_INVALID_ADDRESS) {
+ addr_t dyld_image_info = header_array + (3 * addr_size * i);
+ addr_t addr =
+ process->ReadPointerFromMemory(dyld_image_info, error);
+ if (error.Success()) {
image_load_addresses.push_back(addr);
+ } else {
+ Debugger::ReportWarning(
+ "DynamicLoaderMacOS::NotifyBreakpointHit unable "
+ "to read binary mach-o load address at 0x%" PRIx64,
+ addr);
}
}
if (dyld_mode == 0) {
@@ -362,10 +391,18 @@ bool DynamicLoaderMacOS::NotifyBreakpointHit(void *baton,
Status error;
addr_t notification_addr =
process->ReadPointerFromMemory(notification_location, error);
- if (ABISP abi_sp = process->GetABI())
- notification_addr = abi_sp->FixCodeAddress(notification_addr);
+ if (!error.Success()) {
+ Debugger::ReportWarning(
+ "DynamicLoaderMacOS::NotifyBreakpointHit unable "
+ "to read address of dyld-handover notification function at "
+ "0x%" PRIx64,
+ notification_location);
+ } else {
+ if (ABISP abi_sp = process->GetABI())
+ notification_addr = abi_sp->FixCodeAddress(notification_addr);
- dyld_instance->SetDYLDHandoverBreakpoint(notification_addr);
+ dyld_instance->SetDYLDHandoverBreakpoint(notification_addr);
+ }
}
}
}
@@ -431,9 +468,9 @@ bool DynamicLoaderMacOS::SetNotificationBreakpoint() {
Breakpoint *breakpoint =
m_process->GetTarget()
.CreateBreakpoint(&dyld_filelist, source_files,
- "_dyld_debugger_notification",
- eFunctionNameTypeFull, eLanguageTypeC, 0,
- skip_prologue, internal, hardware)
+ "lldb_image_notifier", eFunctionNameTypeFull,
+ eLanguageTypeC, 0, skip_prologue, internal,
+ hardware)
.get();
breakpoint->SetCallback(DynamicLoaderMacOS::NotifyBreakpointHit, this,
true);
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