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[lldb][AArch64] Add HWCAP3 to register field detection #145029

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Merged
DavidSpickett merged 1 commit into from
Jul 28, 2025
Merged

[lldb][AArch64] Add HWCAP3 to register field detection #145029

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3 changes: 2 additions & 1 deletion lldb/source/Plugins/Process/FreeBSD/NativeRegisterContextFreeBSD_arm64.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -44,7 +44,8 @@ NativeRegisterContextFreeBSD::CreateHostNativeRegisterContextFreeBSD(
NativeProcessFreeBSD &process = native_thread.GetProcess();
g_register_flags_detector.DetectFields(
process.GetAuxValue(AuxVector::AUXV_FREEBSD_AT_HWCAP).value_or(0),
process.GetAuxValue(AuxVector::AUXV_AT_HWCAP2).value_or(0));
process.GetAuxValue(AuxVector::AUXV_AT_HWCAP2).value_or(0),
/*hwcap3=*/0);
}

return new NativeRegisterContextFreeBSD_arm64(target_arch, native_thread);
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5 changes: 4 additions & 1 deletion lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux_arm64.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -162,10 +162,13 @@ NativeRegisterContextLinux::CreateHostNativeRegisterContextLinux(

opt_regsets.Set(RegisterInfoPOSIX_arm64::eRegsetMaskTLS);

std::optional<uint64_t> auxv_at_hwcap3 =
process.GetAuxValue(AuxVector::AUXV_AT_HWCAP3);
std::lock_guard<std::mutex> lock(g_register_flags_detector_mutex);
if (!g_register_flags_detector.HasDetected())
g_register_flags_detector.DetectFields(auxv_at_hwcap.value_or(0),
auxv_at_hwcap2.value_or(0));
auxv_at_hwcap2.value_or(0),
auxv_at_hwcap3.value_or(0));

auto register_info_up =
std::make_unique<RegisterInfoPOSIX_arm64>(target_arch, opt_regsets);
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1 change: 1 addition & 0 deletions lldb/source/Plugins/Process/Utility/AuxVector.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -84,6 +84,7 @@ const char *AuxVector::GetEntryName(EntryType type) const {
case ENTRY_NAME(AUXV_AT_BASE_PLATFORM); break;
case ENTRY_NAME(AUXV_AT_RANDOM); break;
case ENTRY_NAME(AUXV_AT_HWCAP2); break;
case ENTRY_NAME(AUXV_AT_HWCAP3); break;
case ENTRY_NAME(AUXV_AT_EXECFN); break;
case ENTRY_NAME(AUXV_AT_SYSINFO); break;
case ENTRY_NAME(AUXV_AT_SYSINFO_EHDR); break;
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1 change: 1 addition & 0 deletions lldb/source/Plugins/Process/Utility/AuxVector.h
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Expand Up @@ -57,6 +57,7 @@ class AuxVector {
AUXV_AT_BASE_PLATFORM = 24, ///< String identifying real platforms.
AUXV_AT_RANDOM = 25, ///< Address of 16 random bytes.
AUXV_AT_HWCAP2 = 26, ///< Extension of AT_HWCAP.
AUXV_AT_HWCAP3 = 29, ///< Extension of AT_HWCAP.
AUXV_AT_EXECFN = 31, ///< Filename of executable.
AUXV_AT_SYSINFO = 32, ///< Pointer to the global system page used for system
/// calls and other nice things.
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36 changes: 26 additions & 10 deletions lldb/source/Plugins/Process/Utility/RegisterFlagsDetector_arm64.cpp
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Expand Up @@ -29,8 +29,10 @@
using namespace lldb_private;

Arm64RegisterFlagsDetector::Fields
Arm64RegisterFlagsDetector::DetectFPMRFields(uint64_t hwcap, uint64_t hwcap2) {
Arm64RegisterFlagsDetector::DetectFPMRFields(uint64_t hwcap, uint64_t hwcap2,
uint64_t hwcap3) {
(void)hwcap;
(void)hwcap3;
Comment on lines +32 to +35
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Collaborator Author

@DavidSpickett DavidSpickett Jun 20, 2025

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I thought about making the parameters all the same like struct of optional values, but I like the compiler warnings we get from this way.

If we end up with HWCAP4 and a bunch of other context, then yes, some single struct is going to be better. Even if we have a slightly higher chance to get it wrong.


if (!(hwcap2 & HWCAP2_FPMR))
return {};
Expand All @@ -53,8 +55,10 @@ Arm64RegisterFlagsDetector::DetectFPMRFields(uint64_t hwcap, uint64_t hwcap2) {

Arm64RegisterFlagsDetector::Fields
Arm64RegisterFlagsDetector::DetectGCSFeatureFields(uint64_t hwcap,
uint64_t hwcap2) {
uint64_t hwcap2,
uint64_t hwcap3) {
(void)hwcap2;
(void)hwcap3;

if (!(hwcap & HWCAP_GCS))
return {};
Expand All @@ -67,8 +71,10 @@ Arm64RegisterFlagsDetector::DetectGCSFeatureFields(uint64_t hwcap,
}

Arm64RegisterFlagsDetector::Fields
Arm64RegisterFlagsDetector::DetectSVCRFields(uint64_t hwcap, uint64_t hwcap2) {
Arm64RegisterFlagsDetector::DetectSVCRFields(uint64_t hwcap, uint64_t hwcap2,
uint64_t hwcap3) {
(void)hwcap;
(void)hwcap3;

if (!(hwcap2 & HWCAP2_SME))
return {};
Expand All @@ -83,9 +89,10 @@ Arm64RegisterFlagsDetector::DetectSVCRFields(uint64_t hwcap, uint64_t hwcap2) {
}

Arm64RegisterFlagsDetector::Fields
Arm64RegisterFlagsDetector::DetectMTECtrlFields(uint64_t hwcap,
uint64_t hwcap2) {
Arm64RegisterFlagsDetector::DetectMTECtrlFields(uint64_t hwcap, uint64_t hwcap2,
uint64_t hwcap3) {
(void)hwcap;
(void)hwcap3;

if (!(hwcap2 & HWCAP2_MTE))
return {};
Expand All @@ -103,7 +110,10 @@ Arm64RegisterFlagsDetector::DetectMTECtrlFields(uint64_t hwcap,
}

Arm64RegisterFlagsDetector::Fields
Arm64RegisterFlagsDetector::DetectFPCRFields(uint64_t hwcap, uint64_t hwcap2) {
Arm64RegisterFlagsDetector::DetectFPCRFields(uint64_t hwcap, uint64_t hwcap2,
uint64_t hwcap3) {
(void)hwcap3;

static const FieldEnum rmode_enum(
"rmode_enum", {{0, "RN"}, {1, "RP"}, {2, "RM"}, {3, "RZ"}});

Expand Down Expand Up @@ -142,10 +152,12 @@ Arm64RegisterFlagsDetector::DetectFPCRFields(uint64_t hwcap, uint64_t hwcap2) {
}

Arm64RegisterFlagsDetector::Fields
Arm64RegisterFlagsDetector::DetectFPSRFields(uint64_t hwcap, uint64_t hwcap2) {
Arm64RegisterFlagsDetector::DetectFPSRFields(uint64_t hwcap, uint64_t hwcap2,
uint64_t hwcap3) {
// fpsr's contents are constant.
(void)hwcap;
(void)hwcap2;
(void)hwcap3;

return {
// Bits 31-28 are N/Z/C/V, only used by AArch32.
Expand All @@ -162,7 +174,10 @@ Arm64RegisterFlagsDetector::DetectFPSRFields(uint64_t hwcap, uint64_t hwcap2) {
}

Arm64RegisterFlagsDetector::Fields
Arm64RegisterFlagsDetector::DetectCPSRFields(uint64_t hwcap, uint64_t hwcap2) {
Arm64RegisterFlagsDetector::DetectCPSRFields(uint64_t hwcap, uint64_t hwcap2,
uint64_t hwcap3) {
(void)hwcap3;

// The fields here are a combination of the Arm manual's SPSR_EL1,
// plus a few changes where Linux has decided not to make use of them at all,
// or at least not from userspace.
Expand Down Expand Up @@ -207,9 +222,10 @@ Arm64RegisterFlagsDetector::DetectCPSRFields(uint64_t hwcap, uint64_t hwcap2) {
return cpsr_fields;
}

void Arm64RegisterFlagsDetector::DetectFields(uint64_t hwcap, uint64_t hwcap2) {
void Arm64RegisterFlagsDetector::DetectFields(uint64_t hwcap, uint64_t hwcap2,
uint64_t hwcap3) {
for (auto &reg : m_registers)
reg.m_flags.SetFields(reg.m_detector(hwcap, hwcap2));
reg.m_flags.SetFields(reg.m_detector(hwcap, hwcap2, hwcap3));
m_has_detected = true;
}

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25 changes: 16 additions & 9 deletions lldb/source/Plugins/Process/Utility/RegisterFlagsDetector_arm64.h
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Expand Up @@ -40,7 +40,7 @@ class Arm64RegisterFlagsDetector {
/// If called more than once, fields will be redetected each time from
/// scratch. If the target would not have this register at all, the list of
/// fields will be left empty.
void DetectFields(uint64_t hwcap, uint64_t hwcap2);
void DetectFields(uint64_t hwcap, uint64_t hwcap2, uint64_t hwcap3);

/// Add the field information of any registers named in this class,
/// to the relevant RegisterInfo instances. Note that this will be done
Expand All @@ -53,15 +53,22 @@ class Arm64RegisterFlagsDetector {

private:
using Fields = std::vector<RegisterFlags::Field>;
using DetectorFn = std::function<Fields(uint64_t, uint64_t)>;
using DetectorFn = std::function<Fields(uint64_t, uint64_t, uint64_t)>;

static Fields DetectCPSRFields(uint64_t hwcap, uint64_t hwcap2);
static Fields DetectFPSRFields(uint64_t hwcap, uint64_t hwcap2);
static Fields DetectFPCRFields(uint64_t hwcap, uint64_t hwcap2);
static Fields DetectMTECtrlFields(uint64_t hwcap, uint64_t hwcap2);
static Fields DetectSVCRFields(uint64_t hwcap, uint64_t hwcap2);
static Fields DetectFPMRFields(uint64_t hwcap, uint64_t hwcap2);
static Fields DetectGCSFeatureFields(uint64_t hwcap, uint64_t hwcap2);
static Fields DetectCPSRFields(uint64_t hwcap, uint64_t hwcap2,
uint64_t hwcap3);
static Fields DetectFPSRFields(uint64_t hwcap, uint64_t hwcap2,
uint64_t hwcap3);
static Fields DetectFPCRFields(uint64_t hwcap, uint64_t hwcap2,
uint64_t hwcap3);
static Fields DetectMTECtrlFields(uint64_t hwcap, uint64_t hwcap2,
uint64_t hwcap3);
static Fields DetectSVCRFields(uint64_t hwcap, uint64_t hwcap2,
uint64_t hwcap3);
static Fields DetectFPMRFields(uint64_t hwcap, uint64_t hwcap2,
uint64_t hwcap3);
static Fields DetectGCSFeatureFields(uint64_t hwcap, uint64_t hwcap2,
uint64_t hwcap3);

struct RegisterEntry {
RegisterEntry(llvm::StringRef name, unsigned size, DetectorFn detector)
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13 changes: 9 additions & 4 deletions lldb/source/Plugins/Process/elf-core/RegisterContextPOSIXCore_arm64.cpp
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Expand Up @@ -96,14 +96,19 @@ RegisterContextCorePOSIX_arm64::RegisterContextCorePOSIX_arm64(
llvm::Triple::OSType os = process->GetArchitecture().GetTriple().getOS();
if ((os == llvm::Triple::Linux) || (os == llvm::Triple::FreeBSD)) {
AuxVector aux_vec(process->GetAuxvData());
std::optional<uint64_t> auxv_at_hwcap = aux_vec.GetAuxValue(
os == llvm::Triple::FreeBSD ? AuxVector::AUXV_FREEBSD_AT_HWCAP
: AuxVector::AUXV_AT_HWCAP);
bool is_freebsd = os == llvm::Triple::FreeBSD;
std::optional<uint64_t> auxv_at_hwcap =
aux_vec.GetAuxValue(is_freebsd ? AuxVector::AUXV_FREEBSD_AT_HWCAP
: AuxVector::AUXV_AT_HWCAP);
std::optional<uint64_t> auxv_at_hwcap2 =
aux_vec.GetAuxValue(AuxVector::AUXV_AT_HWCAP2);
std::optional<uint64_t> auxv_at_hwcap3 =
is_freebsd ? std::nullopt
: aux_vec.GetAuxValue(AuxVector::AUXV_AT_HWCAP3);

m_register_flags_detector.DetectFields(auxv_at_hwcap.value_or(0),
auxv_at_hwcap2.value_or(0));
auxv_at_hwcap2.value_or(0),
auxv_at_hwcap3.value_or(0));
m_register_flags_detector.UpdateRegisterInfo(GetRegisterInfo(),
GetRegisterCount());
}
Expand Down
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