[Lldb-commits] [PATCH] D96459: [LLDB] Pull AuxVec info into NativeRegisterContextLinux_arm64

[Muhammad Omair Javaid via Phabricator via lldb-commits]

omjavaid created this revision.
omjavaid added a reviewer: labath.
Herald added a subscriber: kristof.beyls.
omjavaid requested review of this revision.

This patch builds on D96458 <https://reviews.llvm.org/D96458> and add ability to pull in Aux Vector HWCAP information into NativeRegisterContextLinux_arm64.

In following up patches we will use this information to decide on whether we need to support certain Arm64 feature registers or not.


https://reviews.llvm.org/D96459

Files:
  lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp
  lldb/source/Plugins/Process/Linux/NativeProcessLinux.h
  lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux_arm64.cpp
  lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux_arm64.h


Index: lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux_arm64.h
===================================================================
--- lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux_arm64.h
+++ lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux_arm64.h
@@ -166,6 +166,8 @@
 
   Status ReadHardwareDebugInfo();
 
+  uint32_t QueryAuxvForOptionalRegset();
+
   Status WriteHardwareDebugRegs(int hwbType);
 
   uint32_t CalculateFprOffset(const RegisterInfo *reg_info) const;
Index: lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux_arm64.cpp
===================================================================
--- lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux_arm64.cpp
+++ lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux_arm64.cpp
@@ -21,6 +21,7 @@
 #include "Plugins/Process/Linux/NativeProcessLinux.h"
 #include "Plugins/Process/Linux/Procfs.h"
 #include "Plugins/Process/POSIX/ProcessPOSIXLog.h"
+#include "Plugins/Process/Utility/AuxVector.h"
 #include "Plugins/Process/Utility/RegisterInfoPOSIX_arm64.h"
 
 // System includes - They have to be included after framework includes because
@@ -84,6 +85,25 @@
   return static_cast<RegisterInfoPOSIX_arm64 &>(*m_register_info_interface_up);
 }
 
+uint32_t NativeRegisterContextLinux_arm64::QueryAuxvForOptionalRegset() {
+  NativeProcessProtocol &process = m_thread.GetProcess();
+  auto buffer_or_error = process.GetAuxvData();
+  if (!buffer_or_error)
+    return 0;
+
+  DataExtractor auxv_data(buffer_or_error.get()->getBufferStart(),
+                          buffer_or_error.get()->getBufferSize(),
+                          process.GetByteOrder(), process.GetAddressByteSize());
+
+  std::unique_ptr<AuxVector> aux_vector =
+      std::make_unique<AuxVector>(auxv_data);
+
+  llvm::Optional<uint64_t> auxv_at_hwcap =
+      aux_vector->GetAuxValue(AuxVector::AUXV_AT_HWCAP);
+
+  return 0;
+}
+
 uint32_t NativeRegisterContextLinux_arm64::GetRegisterSetCount() const {
   return GetRegisterInfo().GetRegisterSetCount();
 }
@@ -1094,8 +1114,8 @@
   // Read SVE configuration data and configure register infos.
   if (!m_sve_header_is_valid && m_sve_state != SVEState::Disabled) {
     Status error = ReadSVEHeader();
-    uint32_t opt_regset = ARM64_REGS_CONFIG_DEFAULT;
     if (m_sve_state == SVEState::Unknown) {
+      uint32_t opt_regset = QueryAuxvForOptionalRegset();
       if (error.Success()) {
         opt_regset |= ARM64_REGS_CONFIG_SVE;
         GetRegisterInfo().ConfigureRegisterInfos(opt_regset);
Index: lldb/source/Plugins/Process/Linux/NativeProcessLinux.h
===================================================================
--- lldb/source/Plugins/Process/Linux/NativeProcessLinux.h
+++ lldb/source/Plugins/Process/Linux/NativeProcessLinux.h
@@ -156,6 +156,8 @@
 
   static Status SetDefaultPtraceOpts(const lldb::pid_t);
 
+  llvm::Optional<uint64_t> GetAuxValue(enum AuxVector::EntryType type);
+
   void MonitorCallback(lldb::pid_t pid, bool exited, WaitStatus status);
 
   void WaitForNewThread(::pid_t tid);
Index: lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp
===================================================================
--- lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp
+++ lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp
@@ -2021,3 +2021,18 @@
 
   return error;
 }
+
+llvm::Optional<uint64_t>
+NativeProcessLinux::GetAuxValue(enum AuxVector::EntryType type) {
+  if (m_aux_vector == nullptr) {
+    auto buffer_or_error = GetAuxvData();
+    if (!buffer_or_error)
+      return llvm::None;
+    DataExtractor auxv_data(buffer_or_error.get()->getBufferStart(),
+                            buffer_or_error.get()->getBufferSize(),
+                            GetByteOrder(), GetAddressByteSize());
+    m_aux_vector = std::make_unique<AuxVector>(auxv_data);
+  }
+
+  return m_aux_vector->GetAuxValue(type);
+}


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