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llvm-project/lldb/source/Plugins/Process/Utility/StopInfoMachException.cpp

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//===-- StopInfoMachException.cpp -----------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "StopInfoMachException.h"
#include "lldb/lldb-forward.h"
#if defined(__APPLE__)
// Needed for the EXC_RESOURCE interpretation macros
#include <kern/exc_resource.h>
#endif
#include "lldb/Breakpoint/Watchpoint.h"
#include "lldb/Symbol/Symbol.h"
#include "lldb/Target/ABI.h"
#include "lldb/Target/DynamicLoader.h"
#include "lldb/Target/ExecutionContext.h"
#include "lldb/Target/Process.h"
#include "lldb/Target/RegisterContext.h"
#include "lldb/Target/Target.h"
#include "lldb/Target/Thread.h"
#include "lldb/Target/ThreadPlan.h"
#include "lldb/Target/UnixSignals.h"
#include "lldb/Utility/StreamString.h"
using namespace lldb;
using namespace lldb_private;
/// Information about a pointer-authentication related instruction.
struct PtrauthInstructionInfo {
bool IsAuthenticated;
bool IsLoad;
bool DoesBranch;
};
/// Get any pointer-authentication related information about the instruction
/// at address \p at_addr.
static llvm::Optional<PtrauthInstructionInfo>
GetPtrauthInstructionInfo(Target &target, const ArchSpec &arch,
const Address &at_addr) {
const char *plugin_name = nullptr;
const char *flavor = nullptr;
AddressRange range_bounds(at_addr, 4);
const bool prefer_file_cache = true;
DisassemblerSP disassembler_sp = Disassembler::DisassembleRange(
arch, plugin_name, flavor, target, range_bounds, prefer_file_cache);
if (!disassembler_sp)
return std::nullopt;
InstructionList &insn_list = disassembler_sp->GetInstructionList();
InstructionSP insn = insn_list.GetInstructionAtIndex(0);
if (!insn)
return std::nullopt;
return PtrauthInstructionInfo{insn->IsAuthenticated(), insn->IsLoad(),
insn->DoesBranch()};
}
/// Describe the load address of \p addr using the format filename:line:col.
static void DescribeAddressBriefly(Stream &strm, const Address &addr,
Target &target) {
strm.Printf("at address=0x%" PRIx64, addr.GetLoadAddress(&target));
StreamString s;
if (addr.GetDescription(s, target, eDescriptionLevelBrief))
strm.Printf(" %s", s.GetString().data());
strm.Printf(".\n");
}
bool StopInfoMachException::DeterminePtrauthFailure(ExecutionContext &exe_ctx) {
bool IsBreakpoint = m_value == 6; // EXC_BREAKPOINT
bool IsBadAccess = m_value == 1; // EXC_BAD_ACCESS
if (!IsBreakpoint && !IsBadAccess)
return false;
// Check that we have a live process.
if (!exe_ctx.HasProcessScope() || !exe_ctx.HasThreadScope() ||
!exe_ctx.HasTargetScope())
return false;
Thread &thread = *exe_ctx.GetThreadPtr();
StackFrameSP current_frame = thread.GetStackFrameAtIndex(0);
if (!current_frame)
return false;
Target &target = *exe_ctx.GetTargetPtr();
Process &process = *exe_ctx.GetProcessPtr();
ABISP abi_sp = process.GetABI();
const ArchSpec &arch = target.GetArchitecture();
assert(abi_sp && "Missing ABI info");
// Check for a ptrauth-enabled target.
const bool ptrauth_enabled_target =
arch.GetCore() == ArchSpec::eCore_arm_arm64e;
if (!ptrauth_enabled_target)
return false;
// Set up a stream we can write a diagnostic into.
StreamString strm;
auto emit_ptrauth_prologue = [&](uint64_t at_address) {
strm.Printf("EXC_BAD_ACCESS (code=%" PRIu64 ", address=0x%" PRIx64 ")\n",
m_exc_code, at_address);
strm.Printf("Note: Possible pointer authentication failure detected.\n");
};
// Check if we have a "brk 0xc47x" trap, where the value that failed to
// authenticate is in x16.
Address current_address = current_frame->GetFrameCodeAddress();
if (IsBreakpoint) {
RegisterContext *reg_ctx = exe_ctx.GetRegisterContext();
if (!reg_ctx)
return false;
const RegisterInfo *X16Info = reg_ctx->GetRegisterInfoByName("x16");
RegisterValue X16Val;
if (!reg_ctx->ReadRegister(X16Info, X16Val))
return false;
uint64_t bad_address = X16Val.GetAsUInt64();
uint64_t fixed_bad_address = abi_sp->FixCodeAddress(bad_address);
Address brk_address;
if (!target.ResolveLoadAddress(fixed_bad_address, brk_address))
return false;
auto brk_ptrauth_info =
GetPtrauthInstructionInfo(target, arch, current_address);
if (brk_ptrauth_info && brk_ptrauth_info->IsAuthenticated) {
emit_ptrauth_prologue(bad_address);
strm.Printf("Found value that failed to authenticate ");
DescribeAddressBriefly(strm, brk_address, target);
m_description = std::string(strm.GetString());
return true;
}
return false;
}
assert(IsBadAccess && "Handle EXC_BAD_ACCESS only after this point");
// Check that we have the "bad address" from an EXC_BAD_ACCESS.
if (m_exc_data_count < 2)
return false;
// Ok, we know the Target is valid and that it describes a ptrauth-enabled
// device. Now, we need to determine whether this exception was caused by a
// ptrauth failure.
uint64_t bad_address = m_exc_subcode;
uint64_t fixed_bad_address = abi_sp->FixCodeAddress(bad_address);
uint64_t current_pc = current_address.GetLoadAddress(&target);
// Detect: LDRAA, LDRAB (Load Register, with pointer authentication).
//
// If an authenticated load results in an exception, the instruction at the
// current PC should be one of LDRAx.
if (bad_address != current_pc && fixed_bad_address != current_pc) {
auto ptrauth_info =
GetPtrauthInstructionInfo(target, arch, current_address);
if (ptrauth_info && ptrauth_info->IsAuthenticated && ptrauth_info->IsLoad) {
emit_ptrauth_prologue(bad_address);
strm.Printf("Found authenticated load instruction ");
DescribeAddressBriefly(strm, current_address, target);
m_description = std::string(strm.GetString());
return true;
}
}
// Detect: BLRAA, BLRAAZ, BLRAB, BLRABZ (Branch with Link to Register, with
// pointer authentication).
//
// TODO: Detect: BRAA, BRAAZ, BRAB, BRABZ (Branch to Register, with pointer
// authentication). At a minimum, this requires call site info support for
// indirect calls.
//
// If an authenticated call or tail call results in an exception, stripping
// the bad address should give the current PC, which points to the address
// we tried to branch to.
if (bad_address != current_pc && fixed_bad_address == current_pc) {
if (StackFrameSP parent_frame = thread.GetStackFrameAtIndex(1)) {
addr_t return_pc =
parent_frame->GetFrameCodeAddress().GetLoadAddress(&target);
Address blr_address;
if (!target.ResolveLoadAddress(return_pc - 4, blr_address))
return false;
auto blr_ptrauth_info =
GetPtrauthInstructionInfo(target, arch, blr_address);
if (blr_ptrauth_info && blr_ptrauth_info->IsAuthenticated &&
blr_ptrauth_info->DoesBranch) {
emit_ptrauth_prologue(bad_address);
strm.Printf("Found authenticated indirect branch ");
DescribeAddressBriefly(strm, blr_address, target);
m_description = std::string(strm.GetString());
return true;
}
}
}
// TODO: Detect: RETAA, RETAB (Return from subroutine, with pointer
// authentication).
//
// Is there a motivating, non-malicious code snippet that corrupts LR?
return false;
}
const char *StopInfoMachException::GetDescription() {
if (!m_description.empty())
return m_description.c_str();
if (GetValue() == eStopReasonInvalid)
return "invalid stop reason!";
ExecutionContext exe_ctx(m_thread_wp.lock());
Target *target = exe_ctx.GetTargetPtr();
const llvm::Triple::ArchType cpu =
target ? target->GetArchitecture().GetMachine()
: llvm::Triple::UnknownArch;
const char *exc_desc = nullptr;
const char *code_label = "code";
const char *code_desc = nullptr;
const char *subcode_label = "subcode";
const char *subcode_desc = nullptr;
#if defined(__APPLE__)
char code_desc_buf[32];
char subcode_desc_buf[32];
#endif
switch (m_value) {
case 1: // EXC_BAD_ACCESS
exc_desc = "EXC_BAD_ACCESS";
subcode_label = "address";
switch (cpu) {
case llvm::Triple::x86:
case llvm::Triple::x86_64:
switch (m_exc_code) {
case 0xd:
code_desc = "EXC_I386_GPFLT";
m_exc_data_count = 1;
break;
}
break;
case llvm::Triple::arm:
case llvm::Triple::thumb:
switch (m_exc_code) {
case 0x101:
code_desc = "EXC_ARM_DA_ALIGN";
break;
case 0x102:
code_desc = "EXC_ARM_DA_DEBUG";
break;
}
break;
case llvm::Triple::aarch64:
if (DeterminePtrauthFailure(exe_ctx))
return m_description.c_str();
break;
default:
break;
}
break;
case 2: // EXC_BAD_INSTRUCTION
exc_desc = "EXC_BAD_INSTRUCTION";
switch (cpu) {
case llvm::Triple::x86:
case llvm::Triple::x86_64:
if (m_exc_code == 1)
code_desc = "EXC_I386_INVOP";
break;
case llvm::Triple::arm:
case llvm::Triple::thumb:
if (m_exc_code == 1)
code_desc = "EXC_ARM_UNDEFINED";
break;
default:
break;
}
break;
case 3: // EXC_ARITHMETIC
exc_desc = "EXC_ARITHMETIC";
switch (cpu) {
case llvm::Triple::x86:
case llvm::Triple::x86_64:
switch (m_exc_code) {
case 1:
code_desc = "EXC_I386_DIV";
break;
case 2:
code_desc = "EXC_I386_INTO";
break;
case 3:
code_desc = "EXC_I386_NOEXT";
break;
case 4:
code_desc = "EXC_I386_EXTOVR";
break;
case 5:
code_desc = "EXC_I386_EXTERR";
break;
case 6:
code_desc = "EXC_I386_EMERR";
break;
case 7:
code_desc = "EXC_I386_BOUND";
break;
case 8:
code_desc = "EXC_I386_SSEEXTERR";
break;
}
break;
default:
break;
}
break;
case 4: // EXC_EMULATION
exc_desc = "EXC_EMULATION";
break;
case 5: // EXC_SOFTWARE
exc_desc = "EXC_SOFTWARE";
if (m_exc_code == 0x10003) {
subcode_desc = "EXC_SOFT_SIGNAL";
subcode_label = "signo";
}
break;
case 6: // EXC_BREAKPOINT
{
exc_desc = "EXC_BREAKPOINT";
switch (cpu) {
case llvm::Triple::x86:
case llvm::Triple::x86_64:
switch (m_exc_code) {
case 1:
code_desc = "EXC_I386_SGL";
break;
case 2:
code_desc = "EXC_I386_BPT";
break;
}
break;
case llvm::Triple::arm:
case llvm::Triple::thumb:
switch (m_exc_code) {
case 0x101:
code_desc = "EXC_ARM_DA_ALIGN";
break;
case 0x102:
code_desc = "EXC_ARM_DA_DEBUG";
break;
case 1:
code_desc = "EXC_ARM_BREAKPOINT";
break;
// FIXME temporary workaround, exc_code 0 does not really mean
// EXC_ARM_BREAKPOINT
case 0:
code_desc = "EXC_ARM_BREAKPOINT";
break;
}
break;
case llvm::Triple::aarch64:
if (DeterminePtrauthFailure(exe_ctx))
return m_description.c_str();
break;
default:
break;
}
} break;
case 7:
exc_desc = "EXC_SYSCALL";
break;
case 8:
exc_desc = "EXC_MACH_SYSCALL";
break;
case 9:
exc_desc = "EXC_RPC_ALERT";
break;
case 10:
exc_desc = "EXC_CRASH";
break;
case 11:
exc_desc = "EXC_RESOURCE";
#if defined(__APPLE__)
{
int resource_type = EXC_RESOURCE_DECODE_RESOURCE_TYPE(m_exc_code);
code_label = "limit";
code_desc = code_desc_buf;
subcode_label = "observed";
subcode_desc = subcode_desc_buf;
switch (resource_type) {
case RESOURCE_TYPE_CPU:
exc_desc =
"EXC_RESOURCE (RESOURCE_TYPE_CPU: CPU usage monitor tripped)";
snprintf(code_desc_buf, sizeof(code_desc_buf), "%d%%",
(int)EXC_RESOURCE_CPUMONITOR_DECODE_PERCENTAGE(m_exc_code));
snprintf(subcode_desc_buf, sizeof(subcode_desc_buf), "%d%%",
(int)EXC_RESOURCE_CPUMONITOR_DECODE_PERCENTAGE_OBSERVED(
m_exc_subcode));
break;
case RESOURCE_TYPE_WAKEUPS:
exc_desc = "EXC_RESOURCE (RESOURCE_TYPE_WAKEUPS: idle wakeups monitor "
"tripped)";
snprintf(
code_desc_buf, sizeof(code_desc_buf), "%d w/s",
(int)EXC_RESOURCE_CPUMONITOR_DECODE_WAKEUPS_PERMITTED(m_exc_code));
snprintf(subcode_desc_buf, sizeof(subcode_desc_buf), "%d w/s",
(int)EXC_RESOURCE_CPUMONITOR_DECODE_WAKEUPS_OBSERVED(
m_exc_subcode));
break;
case RESOURCE_TYPE_MEMORY:
exc_desc = "EXC_RESOURCE (RESOURCE_TYPE_MEMORY: high watermark memory "
"limit exceeded)";
snprintf(code_desc_buf, sizeof(code_desc_buf), "%d MB",
(int)EXC_RESOURCE_HWM_DECODE_LIMIT(m_exc_code));
subcode_desc = nullptr;
subcode_label = nullptr;
break;
#if defined(RESOURCE_TYPE_IO)
// RESOURCE_TYPE_IO is introduced in macOS SDK 10.12.
case RESOURCE_TYPE_IO:
exc_desc = "EXC_RESOURCE RESOURCE_TYPE_IO";
snprintf(code_desc_buf, sizeof(code_desc_buf), "%d MB",
(int)EXC_RESOURCE_IO_DECODE_LIMIT(m_exc_code));
snprintf(subcode_desc_buf, sizeof(subcode_desc_buf), "%d MB",
(int)EXC_RESOURCE_IO_OBSERVED(m_exc_subcode));
;
break;
#endif
}
}
#endif
break;
case 12:
exc_desc = "EXC_GUARD";
break;
}
StreamString strm;
if (exc_desc)
strm.PutCString(exc_desc);
else
strm.Printf("EXC_??? (%" PRIu64 ")", m_value);
if (m_exc_data_count >= 1) {
if (code_desc)
strm.Printf(" (%s=%s", code_label, code_desc);
else
strm.Printf(" (%s=%" PRIu64, code_label, m_exc_code);
}
if (m_exc_data_count >= 2) {
if (subcode_label && subcode_desc)
strm.Printf(", %s=%s", subcode_label, subcode_desc);
else if (subcode_label)
strm.Printf(", %s=0x%" PRIx64, subcode_label, m_exc_subcode);
}
if (m_exc_data_count > 0)
strm.PutChar(')');
m_description = std::string(strm.GetString());
return m_description.c_str();
}
static StopInfoSP GetStopInfoForHardwareBP(Thread &thread, Target *target,
uint32_t exc_data_count,
uint64_t exc_sub_code,
uint64_t exc_sub_sub_code) {
// Try hardware watchpoint.
if (target) {
// The exc_sub_code indicates the data break address.
lldb::WatchpointSP wp_sp =
target->GetWatchpointList().FindByAddress((lldb::addr_t)exc_sub_code);
if (wp_sp && wp_sp->IsEnabled()) {
// Debugserver may piggyback the hardware index of the fired watchpoint
// in the exception data. Set the hardware index if that's the case.
if (exc_data_count >= 3)
wp_sp->SetHardwareIndex((uint32_t)exc_sub_sub_code);
return StopInfo::CreateStopReasonWithWatchpointID(thread, wp_sp->GetID());
}
}
// Try hardware breakpoint.
ProcessSP process_sp(thread.GetProcess());
if (process_sp) {
// The exc_sub_code indicates the data break address.
lldb::BreakpointSiteSP bp_sp =
process_sp->GetBreakpointSiteList().FindByAddress(
(lldb::addr_t)exc_sub_code);
if (bp_sp && bp_sp->IsEnabled()) {
// Debugserver may piggyback the hardware index of the fired breakpoint
// in the exception data. Set the hardware index if that's the case.
if (exc_data_count >= 3)
bp_sp->SetHardwareIndex((uint32_t)exc_sub_sub_code);
return StopInfo::CreateStopReasonWithBreakpointSiteID(thread,
bp_sp->GetID());
}
}
return nullptr;
}
#if defined(__APPLE__)
const char *
StopInfoMachException::MachException::Name(exception_type_t exc_type) {
switch (exc_type) {
case EXC_BAD_ACCESS:
return "EXC_BAD_ACCESS";
case EXC_BAD_INSTRUCTION:
return "EXC_BAD_INSTRUCTION";
case EXC_ARITHMETIC:
return "EXC_ARITHMETIC";
case EXC_EMULATION:
return "EXC_EMULATION";
case EXC_SOFTWARE:
return "EXC_SOFTWARE";
case EXC_BREAKPOINT:
return "EXC_BREAKPOINT";
case EXC_SYSCALL:
return "EXC_SYSCALL";
case EXC_MACH_SYSCALL:
return "EXC_MACH_SYSCALL";
case EXC_RPC_ALERT:
return "EXC_RPC_ALERT";
#ifdef EXC_CRASH
case EXC_CRASH:
return "EXC_CRASH";
#endif
case EXC_RESOURCE:
return "EXC_RESOURCE";
#ifdef EXC_GUARD
case EXC_GUARD:
return "EXC_GUARD";
#endif
#ifdef EXC_CORPSE_NOTIFY
case EXC_CORPSE_NOTIFY:
return "EXC_CORPSE_NOTIFY";
#endif
#ifdef EXC_CORPSE_VARIANT_BIT
case EXC_CORPSE_VARIANT_BIT:
return "EXC_CORPSE_VARIANT_BIT";
#endif
default:
break;
}
return NULL;
}
llvm::Optional<exception_type_t>
StopInfoMachException::MachException::ExceptionCode(const char *name) {
return llvm::StringSwitch<llvm::Optional<exception_type_t>>(name)
.Case("EXC_BAD_ACCESS", EXC_BAD_ACCESS)
.Case("EXC_BAD_INSTRUCTION", EXC_BAD_INSTRUCTION)
.Case("EXC_ARITHMETIC", EXC_ARITHMETIC)
.Case("EXC_EMULATION", EXC_EMULATION)
.Case("EXC_SOFTWARE", EXC_SOFTWARE)
.Case("EXC_BREAKPOINT", EXC_BREAKPOINT)
.Case("EXC_SYSCALL", EXC_SYSCALL)
.Case("EXC_MACH_SYSCALL", EXC_MACH_SYSCALL)
.Case("EXC_RPC_ALERT", EXC_RPC_ALERT)
#ifdef EXC_CRASH
.Case("EXC_CRASH", EXC_CRASH)
#endif
.Case("EXC_RESOURCE", EXC_RESOURCE)
#ifdef EXC_GUARD
.Case("EXC_GUARD", EXC_GUARD)
#endif
#ifdef EXC_CORPSE_NOTIFY
.Case("EXC_CORPSE_NOTIFY", EXC_CORPSE_NOTIFY)
#endif
.Default(llvm::None);
}
#endif
StopInfoSP StopInfoMachException::CreateStopReasonWithMachException(
Thread &thread, uint32_t exc_type, uint32_t exc_data_count,
uint64_t exc_code, uint64_t exc_sub_code, uint64_t exc_sub_sub_code,
bool pc_already_adjusted, bool adjust_pc_if_needed) {
if (exc_type == 0)
return StopInfoSP();
uint32_t pc_decrement = 0;
ExecutionContext exe_ctx(thread.shared_from_this());
Target *target = exe_ctx.GetTargetPtr();
const llvm::Triple::ArchType cpu =
target ? target->GetArchitecture().GetMachine()
: llvm::Triple::UnknownArch;
switch (exc_type) {
case 1: // EXC_BAD_ACCESS
case 2: // EXC_BAD_INSTRUCTION
case 3: // EXC_ARITHMETIC
case 4: // EXC_EMULATION
break;
case 5: // EXC_SOFTWARE
if (exc_code == 0x10003) // EXC_SOFT_SIGNAL
{
if (exc_sub_code == 5) {
// On MacOSX, a SIGTRAP can signify that a process has called exec,
// so we should check with our dynamic loader to verify.
ProcessSP process_sp(thread.GetProcess());
if (process_sp) {
DynamicLoader *dynamic_loader = process_sp->GetDynamicLoader();
if (dynamic_loader && dynamic_loader->ProcessDidExec()) {
// The program was re-exec'ed
return StopInfo::CreateStopReasonWithExec(thread);
}
}
}
return StopInfo::CreateStopReasonWithSignal(thread, exc_sub_code);
}
break;
case 6: // EXC_BREAKPOINT
{
bool is_actual_breakpoint = false;
bool is_trace_if_actual_breakpoint_missing = false;
switch (cpu) {
case llvm::Triple::x86:
case llvm::Triple::x86_64:
if (exc_code == 1) // EXC_I386_SGL
{
if (!exc_sub_code) {
// This looks like a plain trap.
// Have to check if there is a breakpoint here as well. When you
// single-step onto a trap, the single step stops you not to trap.
// Since we also do that check below, let's just use that logic.
is_actual_breakpoint = true;
is_trace_if_actual_breakpoint_missing = true;
} else {
if (StopInfoSP stop_info =
GetStopInfoForHardwareBP(thread, target, exc_data_count,
exc_sub_code, exc_sub_sub_code))
return stop_info;
}
} else if (exc_code == 2 || // EXC_I386_BPT
exc_code == 3) // EXC_I386_BPTFLT
{
// KDP returns EXC_I386_BPTFLT for trace breakpoints
if (exc_code == 3)
is_trace_if_actual_breakpoint_missing = true;
is_actual_breakpoint = true;
if (!pc_already_adjusted)
pc_decrement = 1;
}
break;
case llvm::Triple::arm:
case llvm::Triple::thumb:
if (exc_code == 0x102) // EXC_ARM_DA_DEBUG
{
// It's a watchpoint, then, if the exc_sub_code indicates a
// known/enabled data break address from our watchpoint list.
lldb::WatchpointSP wp_sp;
if (target)
wp_sp = target->GetWatchpointList().FindByAddress(
(lldb::addr_t)exc_sub_code);
if (wp_sp && wp_sp->IsEnabled()) {
// Debugserver may piggyback the hardware index of the fired
// watchpoint in the exception data. Set the hardware index if
// that's the case.
if (exc_data_count >= 3)
wp_sp->SetHardwareIndex((uint32_t)exc_sub_sub_code);
return StopInfo::CreateStopReasonWithWatchpointID(thread,
wp_sp->GetID());
} else {
is_actual_breakpoint = true;
is_trace_if_actual_breakpoint_missing = true;
}
} else if (exc_code == 1) // EXC_ARM_BREAKPOINT
{
is_actual_breakpoint = true;
is_trace_if_actual_breakpoint_missing = true;
} else if (exc_code == 0) // FIXME not EXC_ARM_BREAKPOINT but a kernel
// is currently returning this so accept it
// as indicating a breakpoint until the
// kernel is fixed
{
is_actual_breakpoint = true;
is_trace_if_actual_breakpoint_missing = true;
}
break;
case llvm::Triple::aarch64_32:
case llvm::Triple::aarch64: {
if (exc_code == 1 && exc_sub_code == 0) // EXC_ARM_BREAKPOINT
{
// This is hit when we single instruction step aka MDSCR_EL1 SS bit 0
// is set
is_actual_breakpoint = false;
is_trace_if_actual_breakpoint_missing = true;
}
if (exc_code == 0x102) // EXC_ARM_DA_DEBUG
{
// It's a watchpoint, then, if the exc_sub_code indicates a
// known/enabled data break address from our watchpoint list.
lldb::WatchpointSP wp_sp;
if (target)
wp_sp = target->GetWatchpointList().FindByAddress(
(lldb::addr_t)exc_sub_code);
if (wp_sp && wp_sp->IsEnabled()) {
// Debugserver may piggyback the hardware index of the fired
// watchpoint in the exception data. Set the hardware index if
// that's the case.
if (exc_data_count >= 3)
wp_sp->SetHardwareIndex((uint32_t)exc_sub_sub_code);
return StopInfo::CreateStopReasonWithWatchpointID(thread,
wp_sp->GetID());
}
// EXC_ARM_DA_DEBUG seems to be reused for EXC_BREAKPOINT as well as
// EXC_BAD_ACCESS
if (thread.GetTemporaryResumeState() == eStateStepping)
return StopInfo::CreateStopReasonToTrace(thread);
}
// It looks like exc_sub_code has the 4 bytes of the instruction that
// triggered the exception, i.e. our breakpoint opcode
is_actual_breakpoint = exc_code == 1;
break;
}
default:
break;
}
if (is_actual_breakpoint) {
RegisterContextSP reg_ctx_sp(thread.GetRegisterContext());
addr_t pc = reg_ctx_sp->GetPC() - pc_decrement;
ProcessSP process_sp(thread.CalculateProcess());
lldb::BreakpointSiteSP bp_site_sp;
if (process_sp)
bp_site_sp = process_sp->GetBreakpointSiteList().FindByAddress(pc);
if (bp_site_sp && bp_site_sp->IsEnabled()) {
// Update the PC if we were asked to do so, but only do so if we find
// a breakpoint that we know about cause this could be a trap
// instruction in the code
if (pc_decrement > 0 && adjust_pc_if_needed)
reg_ctx_sp->SetPC(pc);
// If the breakpoint is for this thread, then we'll report the hit,
// but if it is for another thread, we can just report no reason. We
// don't need to worry about stepping over the breakpoint here, that
// will be taken care of when the thread resumes and notices that
// there's a breakpoint under the pc. If we have an operating system
// plug-in, we might have set a thread specific breakpoint using the
// operating system thread ID, so we can't make any assumptions about
// the thread ID so we must always report the breakpoint regardless
// of the thread.
if (bp_site_sp->ValidForThisThread(thread) ||
thread.GetProcess()->GetOperatingSystem() != nullptr)
return StopInfo::CreateStopReasonWithBreakpointSiteID(
thread, bp_site_sp->GetID());
else if (is_trace_if_actual_breakpoint_missing)
return StopInfo::CreateStopReasonToTrace(thread);
else
return StopInfoSP();
}
// Don't call this a trace if we weren't single stepping this thread.
if (is_trace_if_actual_breakpoint_missing &&
thread.GetTemporaryResumeState() == eStateStepping) {
return StopInfo::CreateStopReasonToTrace(thread);
}
}
} break;
case 7: // EXC_SYSCALL
case 8: // EXC_MACH_SYSCALL
case 9: // EXC_RPC_ALERT
case 10: // EXC_CRASH
break;
}
return StopInfoSP(new StopInfoMachException(thread, exc_type, exc_data_count,
exc_code, exc_sub_code));
}
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