[Lldb-commits] [lldb] 9f34f75 - [lldb] [Windows] Fix continuing from breakpoints and singlestepping on ARM/AArch64
Martin Storsjö via lldb-commits
lldb-commits at lists.llvm.org
Wed Sep 22 04:11:52 PDT 2021
Author: Martin Storsjö
Date: 2021-09-22T14:11:41+03:00
New Revision: 9f34f75ff8f49b0efca6e20d916527a2c432d8b4
URL: https://github.com/llvm/llvm-project/commit/9f34f75ff8f49b0efca6e20d916527a2c432d8b4
DIFF: https://github.com/llvm/llvm-project/commit/9f34f75ff8f49b0efca6e20d916527a2c432d8b4.diff
LOG: [lldb] [Windows] Fix continuing from breakpoints and singlestepping on ARM/AArch64
Based on suggestions by Eric Youngdale.
This fixes https://llvm.org/PR51673.
Differential Revision: https://reviews.llvm.org/D109777
Added:
Modified:
lldb/source/Plugins/Platform/Windows/PlatformWindows.cpp
lldb/source/Plugins/Platform/Windows/PlatformWindows.h
lldb/source/Plugins/Process/Windows/Common/NativeProcessWindows.cpp
lldb/source/Plugins/Process/Windows/Common/NativeProcessWindows.h
lldb/source/Plugins/Process/Windows/Common/NativeThreadWindows.cpp
lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp
lldb/source/Plugins/Process/Windows/Common/TargetThreadWindows.cpp
Removed:
################################################################################
diff --git a/lldb/source/Plugins/Platform/Windows/PlatformWindows.cpp b/lldb/source/Plugins/Platform/Windows/PlatformWindows.cpp
index fdb6758c8b7a1..69fa94c12d93a 100644
--- a/lldb/source/Plugins/Platform/Windows/PlatformWindows.cpp
+++ b/lldb/source/Plugins/Platform/Windows/PlatformWindows.cpp
@@ -312,3 +312,38 @@ ConstString PlatformWindows::GetFullNameForDylib(ConstString basename) {
stream.Printf("%s.dll", basename.GetCString());
return ConstString(stream.GetString());
}
+
+size_t
+PlatformWindows::GetSoftwareBreakpointTrapOpcode(Target &target,
+ BreakpointSite *bp_site) {
+ ArchSpec arch = target.GetArchitecture();
+ assert(arch.IsValid());
+ const uint8_t *trap_opcode = nullptr;
+ size_t trap_opcode_size = 0;
+
+ switch (arch.GetMachine()) {
+ case llvm::Triple::aarch64: {
+ static const uint8_t g_aarch64_opcode[] = {0x00, 0x00, 0x3e, 0xd4}; // brk #0xf000
+ trap_opcode = g_aarch64_opcode;
+ trap_opcode_size = sizeof(g_aarch64_opcode);
+
+ if (bp_site->SetTrapOpcode(trap_opcode, trap_opcode_size))
+ return trap_opcode_size;
+ return 0;
+ } break;
+
+ case llvm::Triple::arm:
+ case llvm::Triple::thumb: {
+ static const uint8_t g_thumb_opcode[] = {0xfe, 0xde}; // udf #0xfe
+ trap_opcode = g_thumb_opcode;
+ trap_opcode_size = sizeof(g_thumb_opcode);
+
+ if (bp_site->SetTrapOpcode(trap_opcode, trap_opcode_size))
+ return trap_opcode_size;
+ return 0;
+ } break;
+
+ default:
+ return Platform::GetSoftwareBreakpointTrapOpcode(target, bp_site);
+ }
+}
diff --git a/lldb/source/Plugins/Platform/Windows/PlatformWindows.h b/lldb/source/Plugins/Platform/Windows/PlatformWindows.h
index aff6924e448d5..9bff68f163197 100644
--- a/lldb/source/Plugins/Platform/Windows/PlatformWindows.h
+++ b/lldb/source/Plugins/Platform/Windows/PlatformWindows.h
@@ -61,6 +61,9 @@ class PlatformWindows : public RemoteAwarePlatform {
void CalculateTrapHandlerSymbolNames() override {}
ConstString GetFullNameForDylib(ConstString basename) override;
+
+ size_t GetSoftwareBreakpointTrapOpcode(Target &target,
+ BreakpointSite *bp_site) override;
};
} // namespace lldb_private
diff --git a/lldb/source/Plugins/Process/Windows/Common/NativeProcessWindows.cpp b/lldb/source/Plugins/Process/Windows/Common/NativeProcessWindows.cpp
index 69a5cb20b90b8..5ae878024be17 100644
--- a/lldb/source/Plugins/Process/Windows/Common/NativeProcessWindows.cpp
+++ b/lldb/source/Plugins/Process/Windows/Common/NativeProcessWindows.cpp
@@ -289,6 +289,30 @@ NativeProcessWindows::GetAuxvData() const {
return llvm::errc::not_supported;
}
+llvm::Expected<llvm::ArrayRef<uint8_t>>
+NativeProcessWindows::GetSoftwareBreakpointTrapOpcode(size_t size_hint) {
+ static const uint8_t g_aarch64_opcode[] = {0x00, 0x00, 0x3e, 0xd4}; // brk #0xf000
+ static const uint8_t g_thumb_opcode[] = {0xfe, 0xde}; // udf #0xfe
+
+ switch (GetArchitecture().GetMachine()) {
+ case llvm::Triple::aarch64:
+ return llvm::makeArrayRef(g_aarch64_opcode);
+
+ case llvm::Triple::arm:
+ case llvm::Triple::thumb:
+ return llvm::makeArrayRef(g_thumb_opcode);
+
+ default:
+ return NativeProcessProtocol::GetSoftwareBreakpointTrapOpcode(size_hint);
+ }
+}
+
+size_t NativeProcessWindows::GetSoftwareBreakpointPCOffset() {
+ // Windows always reports an incremented PC after a breakpoint is hit,
+ // even on ARM.
+ return cantFail(GetSoftwareBreakpointTrapOpcode(0)).size();
+}
+
bool NativeProcessWindows::FindSoftwareBreakpoint(lldb::addr_t addr) {
auto it = m_software_breakpoints.find(addr);
if (it == m_software_breakpoints.end())
@@ -474,8 +498,9 @@ NativeProcessWindows::OnDebugException(bool first_chance,
if (NativeThreadWindows *stop_thread =
GetThreadByID(record.GetThreadID())) {
auto ®ister_context = stop_thread->GetRegisterContext();
- // The current EIP is AFTER the BP opcode, which is one byte '0xCC'
- uint64_t pc = register_context.GetPC() - 1;
+ uint32_t breakpoint_size = GetSoftwareBreakpointPCOffset();
+ // The current PC is AFTER the BP opcode, on all architectures.
+ uint64_t pc = register_context.GetPC() - breakpoint_size;
register_context.SetPC(pc);
}
diff --git a/lldb/source/Plugins/Process/Windows/Common/NativeProcessWindows.h b/lldb/source/Plugins/Process/Windows/Common/NativeProcessWindows.h
index 150f7083e8691..6c83733346227 100644
--- a/lldb/source/Plugins/Process/Windows/Common/NativeProcessWindows.h
+++ b/lldb/source/Plugins/Process/Windows/Common/NativeProcessWindows.h
@@ -108,6 +108,11 @@ class NativeProcessWindows : public NativeProcessProtocol,
protected:
NativeThreadWindows *GetThreadByID(lldb::tid_t thread_id);
+ llvm::Expected<llvm::ArrayRef<uint8_t>>
+ GetSoftwareBreakpointTrapOpcode(size_t size_hint) override;
+
+ size_t GetSoftwareBreakpointPCOffset() override;
+
bool FindSoftwareBreakpoint(lldb::addr_t addr);
void StopThread(lldb::tid_t thread_id, lldb::StopReason reason,
diff --git a/lldb/source/Plugins/Process/Windows/Common/NativeThreadWindows.cpp b/lldb/source/Plugins/Process/Windows/Common/NativeThreadWindows.cpp
index 16e67bb9f8632..b2b16cdeee718 100644
--- a/lldb/source/Plugins/Process/Windows/Common/NativeThreadWindows.cpp
+++ b/lldb/source/Plugins/Process/Windows/Common/NativeThreadWindows.cpp
@@ -48,12 +48,29 @@ Status NativeThreadWindows::DoResume(lldb::StateType resume_state) {
return Status();
if (resume_state == eStateStepping) {
+ Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_THREAD));
+
uint32_t flags_index =
GetRegisterContext().ConvertRegisterKindToRegisterNumber(
eRegisterKindGeneric, LLDB_REGNUM_GENERIC_FLAGS);
uint64_t flags_value =
GetRegisterContext().ReadRegisterAsUnsigned(flags_index, 0);
- flags_value |= 0x100; // Set the trap flag on the CPU
+ NativeProcessProtocol &process = GetProcess();
+ const ArchSpec &arch = process.GetArchitecture();
+ switch (arch.GetMachine()) {
+ case llvm::Triple::x86:
+ case llvm::Triple::x86_64:
+ flags_value |= 0x100; // Set the trap flag on the CPU
+ break;
+ case llvm::Triple::aarch64:
+ case llvm::Triple::arm:
+ case llvm::Triple::thumb:
+ flags_value |= 0x200000; // The SS bit in PState
+ break;
+ default:
+ LLDB_LOG(log, "single stepping unsupported on this architecture");
+ break;
+ }
GetRegisterContext().WriteRegisterFromUnsigned(flags_index, flags_value);
}
diff --git a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp
index 2b692b2ecd4dd..74efa35f962f4 100644
--- a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp
+++ b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp
@@ -436,8 +436,29 @@ void ProcessWindows::RefreshStateAfterStop() {
case EXCEPTION_BREAKPOINT: {
RegisterContextSP register_context = stop_thread->GetRegisterContext();
- // The current EIP is AFTER the BP opcode, which is one byte.
- uint64_t pc = register_context->GetPC() - 1;
+ int breakpoint_size = 1;
+ switch (GetTarget().GetArchitecture().GetMachine()) {
+ case llvm::Triple::aarch64:
+ breakpoint_size = 4;
+ break;
+
+ case llvm::Triple::arm:
+ case llvm::Triple::thumb:
+ breakpoint_size = 2;
+ break;
+
+ case llvm::Triple::x86:
+ case llvm::Triple::x86_64:
+ breakpoint_size = 1;
+ break;
+
+ default:
+ LLDB_LOG(log, "Unknown breakpoint size for architecture");
+ break;
+ }
+
+ // The current PC is AFTER the BP opcode, on all architectures.
+ uint64_t pc = register_context->GetPC() - breakpoint_size;
BreakpointSiteSP site(GetBreakpointSiteList().FindByAddress(pc));
if (site) {
diff --git a/lldb/source/Plugins/Process/Windows/Common/TargetThreadWindows.cpp b/lldb/source/Plugins/Process/Windows/Common/TargetThreadWindows.cpp
index 6d608b2b6ce35..9810d21eb224f 100644
--- a/lldb/source/Plugins/Process/Windows/Common/TargetThreadWindows.cpp
+++ b/lldb/source/Plugins/Process/Windows/Common/TargetThreadWindows.cpp
@@ -131,12 +131,29 @@ Status TargetThreadWindows::DoResume() {
return Status();
if (resume_state == eStateStepping) {
+ Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_THREAD));
+
uint32_t flags_index =
GetRegisterContext()->ConvertRegisterKindToRegisterNumber(
eRegisterKindGeneric, LLDB_REGNUM_GENERIC_FLAGS);
uint64_t flags_value =
GetRegisterContext()->ReadRegisterAsUnsigned(flags_index, 0);
- flags_value |= 0x100; // Set the trap flag on the CPU
+ ProcessSP process = GetProcess();
+ const ArchSpec &arch = process->GetTarget().GetArchitecture();
+ switch (arch.GetMachine()) {
+ case llvm::Triple::x86:
+ case llvm::Triple::x86_64:
+ flags_value |= 0x100; // Set the trap flag on the CPU
+ break;
+ case llvm::Triple::aarch64:
+ case llvm::Triple::arm:
+ case llvm::Triple::thumb:
+ flags_value |= 0x200000; // The SS bit in PState
+ break;
+ default:
+ LLDB_LOG(log, "single stepping unsupported on this architecture");
+ break;
+ }
GetRegisterContext()->WriteRegisterFromUnsigned(flags_index, flags_value);
}
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