[Lldb-commits] [lldb] [lldb][Process/FreeBSDKernel] Fix broken debugging on aarch64 (PR #180222)

[via lldb-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-lldb

Author: Minsoo Choo (mchoo7)

<details>
<summary>Changes</summary>

`struct pcb` for arm64 has changed In https://github.com/freebsd/freebsd-src/commit/1c1f31a5e517ebb940c752c3468b03cdc687c5c7#diff-d07b4e228ca340857a90658e328d65f8dea9c5063e99197fbaaa046d97ae927c, which broke kernel debugging on AArch64. This updates to the latest pcb structure which has been in effect since FreeBSD 14.

---
Full diff: https://github.com/llvm/llvm-project/pull/180222.diff


1 Files Affected:

- (modified) lldb/source/Plugins/Process/FreeBSDKernel/RegisterContextFreeBSDKernel_arm64.cpp (+13-28) 


``````````diff
diff --git a/lldb/source/Plugins/Process/FreeBSDKernel/RegisterContextFreeBSDKernel_arm64.cpp b/lldb/source/Plugins/Process/FreeBSDKernel/RegisterContextFreeBSDKernel_arm64.cpp
index 11843ddc82d97..68944418b9a83 100644
--- a/lldb/source/Plugins/Process/FreeBSDKernel/RegisterContextFreeBSDKernel_arm64.cpp
+++ b/lldb/source/Plugins/Process/FreeBSDKernel/RegisterContextFreeBSDKernel_arm64.cpp
@@ -43,9 +43,10 @@ bool RegisterContextFreeBSDKernel_arm64::ReadRegister(
     return false;
 
   struct {
-    llvm::support::ulittle64_t x[30];
-    llvm::support::ulittle64_t lr;
-    llvm::support::ulittle64_t _reserved;
+#define	PCB_FP		10
+#define	PCB_LR		11
+
+    llvm::support::ulittle64_t x[12];
     llvm::support::ulittle64_t sp;
   } pcb;
 
@@ -57,25 +58,6 @@ bool RegisterContextFreeBSDKernel_arm64::ReadRegister(
 
   uint32_t reg = reg_info->kinds[lldb::eRegisterKindLLDB];
   switch (reg) {
-  case gpr_x0_arm64:
-  case gpr_x1_arm64:
-  case gpr_x2_arm64:
-  case gpr_x3_arm64:
-  case gpr_x4_arm64:
-  case gpr_x5_arm64:
-  case gpr_x6_arm64:
-  case gpr_x7_arm64:
-  case gpr_x8_arm64:
-  case gpr_x9_arm64:
-  case gpr_x10_arm64:
-  case gpr_x11_arm64:
-  case gpr_x12_arm64:
-  case gpr_x13_arm64:
-  case gpr_x14_arm64:
-  case gpr_x15_arm64:
-  case gpr_x16_arm64:
-  case gpr_x17_arm64:
-  case gpr_x18_arm64:
   case gpr_x19_arm64:
   case gpr_x20_arm64:
   case gpr_x21_arm64:
@@ -87,16 +69,19 @@ bool RegisterContextFreeBSDKernel_arm64::ReadRegister(
   case gpr_x27_arm64:
   case gpr_x28_arm64:
   case gpr_fp_arm64:
-    static_assert(gpr_fp_arm64 - gpr_x0_arm64 == 29,
+    static_assert(gpr_fp_arm64 - gpr_x19_arm64 == PCB_FP,
                   "nonconsecutive arm64 register numbers");
-    value = pcb.x[reg - gpr_x0_arm64];
-    break;
-  case gpr_sp_arm64:
-    value = pcb.sp;
+    value = pcb.x[reg - gpr_x19_arm64];
     break;
+  case gpr_lr_arm64:
   case gpr_pc_arm64:
     // The pc of crashing thread is stored in lr.
-    value = pcb.lr;
+    static_assert(gpr_lr_arm64 - gpr_x19_arm64 == PCB_LR,
+                  "nonconsecutive arm64 register numbers");
+    value = pcb.x[reg - gpr_x19_arm64];
+    break;
+  case gpr_sp_arm64:
+    value = pcb.sp;
     break;
   default:
     return false;

``````````

</details>


https://github.com/llvm/llvm-project/pull/180222