[Lldb-commits] [lldb] [lldb][FreeBSDKernel] Implement trapframe unwinding (PR #192184)

[David Spickett via lldb-commits]

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@@ -0,0 +1,60 @@
+//===----------------------------------------------------------------------===//
+//
+// 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 "PlatformFreeBSDKernel.h"
+
+#include <cstddef>
+#if defined(__FreeBSD__) && defined(__aarch64__)
+#include <machine/frame.h>
+#endif
+
+using namespace lldb_private::platform_freebsdkernel;
+
+// DWARF register numbers for AArch64.
+static constexpr uint32_t kDwarfSP = 31;
+static constexpr uint32_t kDwarfPC = 32;
+static constexpr uint32_t kDwarfLR = 30;   // x30
+static constexpr uint32_t kDwarfCPSR = 33; // PSTATE / CPSR
+
+// Trapframe byte offsets.
+// struct trapframe layout (sys/arm64/include/frame.h, FreeBSD 14+):
+static constexpr int32_t kTfSP = 0;
+static constexpr int32_t kTfLR = 8;
+static constexpr int32_t kTfELR = 16;    // saved PC
+static constexpr int32_t kTfSPSR = 24;   // cpsr
+static constexpr int32_t kTfX0Base = 48; // tf_x[0]; tf_x[n] = kTfX0Base + n*8
+
+#if defined(__FreeBSD__) && defined(__aarch64__)
+static_assert(offsetof(struct trapframe, tf_sp) == (size_t)kTfSP,
+              "tf_sp offset mismatch");
+static_assert(offsetof(struct trapframe, tf_lr) == (size_t)kTfLR,
+              "tf_lr offset mismatch");
+static_assert(offsetof(struct trapframe, tf_elr) == (size_t)kTfELR,
+              "tf_elr offset mismatch");
+static_assert(offsetof(struct trapframe, tf_spsr) == (size_t)kTfSPSR,
+              "tf_spsr offset mismatch");
+static_assert(offsetof(struct trapframe, tf_x[0]) == (size_t)kTfX0Base,
+              "tf_x[0] offset mismatch");
+#endif
+
+lldb::UnwindPlanSP
+PlatformFreeBSDKernel::GetTrapframeUnwindPlan_arm64(ConstString name) {
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DavidSpickett wrote:

These functions need to use the name or not. Either they set their names to "FreeBSD aarch64 trapframe for [the name]", or they don't, and you mark the parameter `maybe_unused`.

Perhaps you're thinking you'll need it for arm and i386 where the plans are unique per function, in which case I'd just mark it unused in the ones you're adding here. Since every plan is the same for them.

https://github.com/llvm/llvm-project/pull/192184