[Lldb-commits] [lldb] [lldb] Add RegisterContextPOSIXCore for RISC-V 64 (PR #93297)

[Jason Molenda via lldb-commits]

================
@@ -0,0 +1,84 @@
+//===-- RegisterContextPOSIXCore_riscv64.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 "RegisterContextPOSIXCore_riscv64.h"
+
+#include "lldb/Utility/DataBufferHeap.h"
+
+using namespace lldb_private;
+
+std::unique_ptr<RegisterContextCorePOSIX_riscv64>
+RegisterContextCorePOSIX_riscv64::Create(
+    lldb_private::Thread &thread, const lldb_private::ArchSpec &arch,
+    const lldb_private::DataExtractor &gpregset,
+    llvm::ArrayRef<lldb_private::CoreNote> notes) {
+  Flags flags = 0;
+
+  auto register_info_up =
+      std::make_unique<RegisterInfoPOSIX_riscv64>(arch, flags);
+  return std::unique_ptr<RegisterContextCorePOSIX_riscv64>(
+      new RegisterContextCorePOSIX_riscv64(thread, std::move(register_info_up),
+                                           gpregset, notes));
+}
+
+RegisterContextCorePOSIX_riscv64::RegisterContextCorePOSIX_riscv64(
+    Thread &thread, std::unique_ptr<RegisterInfoPOSIX_riscv64> register_info,
+    const DataExtractor &gpregset, llvm::ArrayRef<CoreNote> notes)
+    : RegisterContextPOSIX_riscv64(thread, std::move(register_info)) {
+
+  m_gpr_buffer = std::make_shared<DataBufferHeap>(gpregset.GetDataStart(),
+                                                  gpregset.GetByteSize());
+  m_gpr.SetData(m_gpr_buffer);
+  m_gpr.SetByteOrder(gpregset.GetByteOrder());
+
+  ArchSpec arch = m_register_info_up->GetTargetArchitecture();
+  DataExtractor fpregset = getRegset(notes, arch.GetTriple(), FPR_Desc);
+  m_fpr_buffer = std::make_shared<DataBufferHeap>(fpregset.GetDataStart(),
----------------
jasonmolenda wrote:

I see in the aarch64 elf core plugin that it checks the size of the DataExtractor object before setting the buffer to its contents, with a "must be bigger than the smallest possible size", e.g. 

```
  DataExtractor mte_data = getRegset(notes, arch.GetTriple(), AARCH64_MTE_Desc);
  if (mte_data.GetByteSize() >= sizeof(uint64_t))
    opt_regsets.Set(RegisterInfoPOSIX_arm64::eRegsetMaskMTE);
```

Is it possible this could be called without a floating point register context?  I know in RISC-V nearly anything is possible :) but maybe realistically we're always going to have an fpr.

https://github.com/llvm/llvm-project/pull/93297