[Lldb-commits] [lldb] [lldb] Step over non-lldb breakpoints (PR #190622)
Jason Molenda via lldb-commits
lldb-commits at lists.llvm.org
Tue Apr 7 23:01:32 PDT 2026
================
@@ -2028,146 +2029,171 @@ size_t Platform::ConnectToWaitingProcesses(lldb_private::Debugger &debugger,
return 0;
}
-size_t Platform::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;
+llvm::ArrayRef<uint8_t> Platform::SoftwareTrapOpcodeBytes(const ArchSpec &arch,
+ size_t size_hint) {
+ llvm::ArrayRef<uint8_t> trap_opcode;
switch (arch.GetMachine()) {
case llvm::Triple::aarch64_32:
case llvm::Triple::aarch64: {
static const uint8_t g_aarch64_opcode[] = {0x00, 0x00, 0x20, 0xd4};
- trap_opcode = g_aarch64_opcode;
- trap_opcode_size = sizeof(g_aarch64_opcode);
+ trap_opcode =
+ llvm::ArrayRef<uint8_t>(g_aarch64_opcode, sizeof(g_aarch64_opcode));
} break;
case llvm::Triple::arc: {
- static const uint8_t g_hex_opcode[] = { 0xff, 0x7f };
- trap_opcode = g_hex_opcode;
- trap_opcode_size = sizeof(g_hex_opcode);
+ static const uint8_t g_hex_opcode[] = {0xff, 0x7f};
+ trap_opcode = llvm::ArrayRef<uint8_t>(g_hex_opcode, sizeof(g_hex_opcode));
} break;
- // TODO: support big-endian arm and thumb trap codes.
case llvm::Triple::arm: {
- // The ARM reference recommends the use of 0xe7fddefe and 0xdefe but the
- // linux kernel does otherwise.
+ // ARM CPUs have dedicated BKPT instructions: 0xe7fddefe and 0xdefe.
+ // However, the linux kernel recognizes two different sequences based on
+ // undefined instruction encodings (linux/arch/arm/kernel/ptrace.c)
static const uint8_t g_arm_breakpoint_opcode[] = {0xf0, 0x01, 0xf0, 0xe7};
static const uint8_t g_thumb_breakpoint_opcode[] = {0x01, 0xde};
- lldb::BreakpointLocationSP bp_loc_sp(bp_site->GetConstituentAtIndex(0));
- AddressClass addr_class = AddressClass::eUnknown;
-
- if (bp_loc_sp) {
- addr_class = bp_loc_sp->GetAddress().GetAddressClass();
- if (addr_class == AddressClass::eUnknown &&
- (bp_loc_sp->GetAddress().GetFileAddress() & 1))
- addr_class = AddressClass::eCodeAlternateISA;
- }
-
- if (addr_class == AddressClass::eCodeAlternateISA) {
- trap_opcode = g_thumb_breakpoint_opcode;
- trap_opcode_size = sizeof(g_thumb_breakpoint_opcode);
+ if (size_hint == 2) {
+ trap_opcode = llvm::ArrayRef<uint8_t>(g_thumb_breakpoint_opcode,
+ sizeof(g_thumb_breakpoint_opcode));
} else {
- trap_opcode = g_arm_breakpoint_opcode;
- trap_opcode_size = sizeof(g_arm_breakpoint_opcode);
+ trap_opcode = llvm::ArrayRef<uint8_t>(g_arm_breakpoint_opcode,
+ sizeof(g_arm_breakpoint_opcode));
}
} break;
case llvm::Triple::avr: {
static const uint8_t g_hex_opcode[] = {0x98, 0x95};
- trap_opcode = g_hex_opcode;
- trap_opcode_size = sizeof(g_hex_opcode);
+ trap_opcode = llvm::ArrayRef<uint8_t>(g_hex_opcode, sizeof(g_hex_opcode));
} break;
case llvm::Triple::mips:
case llvm::Triple::mips64: {
static const uint8_t g_hex_opcode[] = {0x00, 0x00, 0x00, 0x0d};
- trap_opcode = g_hex_opcode;
- trap_opcode_size = sizeof(g_hex_opcode);
+ trap_opcode = llvm::ArrayRef<uint8_t>(g_hex_opcode, sizeof(g_hex_opcode));
} break;
case llvm::Triple::mipsel:
case llvm::Triple::mips64el: {
static const uint8_t g_hex_opcode[] = {0x0d, 0x00, 0x00, 0x00};
- trap_opcode = g_hex_opcode;
- trap_opcode_size = sizeof(g_hex_opcode);
+ trap_opcode = llvm::ArrayRef<uint8_t>(g_hex_opcode, sizeof(g_hex_opcode));
} break;
case llvm::Triple::msp430: {
static const uint8_t g_msp430_opcode[] = {0x43, 0x43};
- trap_opcode = g_msp430_opcode;
- trap_opcode_size = sizeof(g_msp430_opcode);
+ trap_opcode =
+ llvm::ArrayRef<uint8_t>(g_msp430_opcode, sizeof(g_msp430_opcode));
} break;
case llvm::Triple::systemz: {
static const uint8_t g_hex_opcode[] = {0x00, 0x01};
- trap_opcode = g_hex_opcode;
- trap_opcode_size = sizeof(g_hex_opcode);
+ trap_opcode = llvm::ArrayRef<uint8_t>(g_hex_opcode, sizeof(g_hex_opcode));
} break;
case llvm::Triple::hexagon: {
static const uint8_t g_hex_opcode[] = {0x0c, 0xdb, 0x00, 0x54};
- trap_opcode = g_hex_opcode;
- trap_opcode_size = sizeof(g_hex_opcode);
+ trap_opcode = llvm::ArrayRef<uint8_t>(g_hex_opcode, sizeof(g_hex_opcode));
} break;
case llvm::Triple::ppc:
case llvm::Triple::ppc64: {
static const uint8_t g_ppc_opcode[] = {0x7f, 0xe0, 0x00, 0x08};
- trap_opcode = g_ppc_opcode;
- trap_opcode_size = sizeof(g_ppc_opcode);
+ trap_opcode = llvm::ArrayRef<uint8_t>(g_ppc_opcode, sizeof(g_ppc_opcode));
} break;
case llvm::Triple::ppc64le: {
static const uint8_t g_ppc64le_opcode[] = {0x08, 0x00, 0xe0, 0x7f}; // trap
- trap_opcode = g_ppc64le_opcode;
- trap_opcode_size = sizeof(g_ppc64le_opcode);
+ trap_opcode =
+ llvm::ArrayRef<uint8_t>(g_ppc64le_opcode, sizeof(g_ppc64le_opcode));
} break;
case llvm::Triple::x86:
case llvm::Triple::x86_64: {
static const uint8_t g_i386_opcode[] = {0xCC};
- trap_opcode = g_i386_opcode;
- trap_opcode_size = sizeof(g_i386_opcode);
+ trap_opcode = llvm::ArrayRef<uint8_t>(g_i386_opcode, sizeof(g_i386_opcode));
} break;
case llvm::Triple::riscv32:
case llvm::Triple::riscv64: {
static const uint8_t g_riscv_opcode[] = {0x73, 0x00, 0x10, 0x00}; // ebreak
static const uint8_t g_riscv_opcode_c[] = {0x02, 0x90}; // c.ebreak
- if (arch.GetFlags() & ArchSpec::eRISCV_rvc) {
+ if (size_hint == 2) {
trap_opcode = g_riscv_opcode_c;
- trap_opcode_size = sizeof(g_riscv_opcode_c);
} else {
- trap_opcode = g_riscv_opcode;
- trap_opcode_size = sizeof(g_riscv_opcode);
+ trap_opcode =
+ llvm::ArrayRef<uint8_t>(g_riscv_opcode, sizeof(g_riscv_opcode));
}
} break;
case llvm::Triple::loongarch32:
case llvm::Triple::loongarch64: {
static const uint8_t g_loongarch_opcode[] = {0x05, 0x00, 0x2a,
0x00}; // break 0x5
- trap_opcode = g_loongarch_opcode;
- trap_opcode_size = sizeof(g_loongarch_opcode);
+ trap_opcode =
+ llvm::ArrayRef<uint8_t>(g_loongarch_opcode, sizeof(g_loongarch_opcode));
} break;
+ // Unreachable (0x00) triggers an unconditional trap.
case llvm::Triple::wasm32: {
- // Unreachable (0x00) triggers an unconditional trap.
static const uint8_t g_wasm_opcode[] = {0x00};
- trap_opcode = g_wasm_opcode;
- trap_opcode_size = sizeof(g_wasm_opcode);
+ trap_opcode = llvm::ArrayRef<uint8_t>(g_wasm_opcode, sizeof(g_wasm_opcode));
} break;
+ // The default case should not match against anything, so return empty Array.
+ default: {
+ trap_opcode = llvm::ArrayRef<uint8_t>{};
+ };
+ }
+ return trap_opcode;
+}
- default:
- return 0;
+size_t Platform::GetTrapOpcodeSizeHint(Target &target, Address addr,
+ llvm::ArrayRef<uint8_t> bytes) {
+ ArchSpec arch = target.GetArchitecture();
+ assert(arch.IsValid());
+ const auto &triple = arch.GetTriple();
+
+ if (bytes.size() && triple.isRISCV()) {
+ // RISC-V instructions have the two LSB as 0b11 if they are four-byte.
+ return (bytes[0] & 0b11) == 0b11 ? 4 : 2;
}
- assert(bp_site);
- if (bp_site->SetTrapOpcode(trap_opcode, trap_opcode_size))
- return trap_opcode_size;
+ if (triple.isARM()) {
+ if (auto addr_class = addr.GetAddressClass();
+ addr_class == AddressClass::eCodeAlternateISA) {
+ return 2;
+ } else {
+ return 4;
+ }
+ }
+ return 0;
+}
+
+size_t Platform::GetSoftwareBreakpointTrapOpcode(Target &target,
+ BreakpointSite *bp_site) {
+ ArchSpec arch = target.GetArchitecture();
+ assert(arch.IsValid());
+ AddressClass addr_class = AddressClass::eUnknown;
+ if (bp_site) {
+ // TODO: support big-endian arm and thumb trap codes.
+ lldb::BreakpointLocationSP bp_loc_sp(bp_site->GetConstituentAtIndex(0));
+ if (bp_loc_sp) {
+ addr_class = bp_loc_sp->GetAddress().GetAddressClass();
+ if (addr_class == AddressClass::eUnknown &&
+ (bp_loc_sp->GetAddress().GetFileAddress() & 1))
+ addr_class = AddressClass::eCodeAlternateISA;
+ }
+ }
+
+ size_t size_hint = 0;
+ // Check for either ARM or RISC-V short instruction conditions.
+ if ((addr_class == AddressClass::eCodeAlternateISA) ||
----------------
jasonmolenda wrote:
minor nit, but the extra parentheses around (a==b) aren't adding anything, is it just for symmetry for the `||(a&b)` which i'll be honest i had to look up to double check whether it was necessary, so probably better to leave the parens for the second half of this, so no one gets worried about it.
https://github.com/llvm/llvm-project/pull/190622
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