[Lldb-commits] [lldb] Fix empty register set when trying to get size of register (PR #162890)

[via lldb-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-lldb

Author: None (aokblast)

<details>
<summary>Changes</summary>

GetSharedRegisterInfoVector is a function to get the singleton of total register info. Also, PrivateGetRegisterCount assumes that we have already filled the object in GetSharedRegisterInfoVector and panic when the object is empty.
However, the actually function possess the register info is GetRegisterInfo_i386. Originally, I plan to solve this by only referencing object in GetSharedRegisterInfoVector. However, RegisterInfos_x86_64.h requires the symbol with name g_register_infos in current scope so that the header can append x86_64 registers after it. As a result, I decide to copy the info to the object in GetSharedRegisterInfoVector.

Also, reorder the header order and provide a test for debugging 32bit binary on 64bit platform.

---
Full diff: https://github.com/llvm/llvm-project/pull/162890.diff


2 Files Affected:

- (modified) lldb/source/Host/freebsd/Host.cpp (+1-2) 
- (modified) lldb/source/Plugins/Process/Utility/RegisterContextFreeBSD_x86_64.cpp (+4-2) 


``````````diff
diff --git a/lldb/source/Host/freebsd/Host.cpp b/lldb/source/Host/freebsd/Host.cpp
index fa7efad466bad..dfdbfea0c3c0a 100644
--- a/lldb/source/Host/freebsd/Host.cpp
+++ b/lldb/source/Host/freebsd/Host.cpp
@@ -18,8 +18,6 @@
 #include <dlfcn.h>
 #include <execinfo.h>
 
-#include "llvm/Object/ELF.h"
-
 #include "lldb/Host/FileSystem.h"
 #include "lldb/Host/Host.h"
 #include "lldb/Host/HostInfo.h"
@@ -32,6 +30,7 @@
 #include "lldb/Utility/Status.h"
 #include "lldb/Utility/StreamString.h"
 
+#include "llvm/Object/ELF.h"
 #include "llvm/TargetParser/Host.h"
 
 namespace lldb_private {
diff --git a/lldb/source/Plugins/Process/Utility/RegisterContextFreeBSD_x86_64.cpp b/lldb/source/Plugins/Process/Utility/RegisterContextFreeBSD_x86_64.cpp
index e0f3971c6e272..b55a5c595d3ca 100644
--- a/lldb/source/Plugins/Process/Utility/RegisterContextFreeBSD_x86_64.cpp
+++ b/lldb/source/Plugins/Process/Utility/RegisterContextFreeBSD_x86_64.cpp
@@ -76,8 +76,7 @@ static std::vector<lldb_private::RegisterInfo> &GetSharedRegisterInfoVector() {
 
 static const RegisterInfo *
 GetRegisterInfo_i386(const lldb_private::ArchSpec &arch) {
-  static std::vector<lldb_private::RegisterInfo> g_register_infos(
-      GetSharedRegisterInfoVector());
+  static std::vector<lldb_private::RegisterInfo> g_register_infos;
 
   // Allocate RegisterInfo only once
   if (g_register_infos.empty()) {
@@ -93,6 +92,9 @@ GetRegisterInfo_i386(const lldb_private::ArchSpec &arch) {
 #define UPDATE_REGISTER_INFOS_I386_STRUCT_WITH_X86_64_OFFSETS
 #include "RegisterInfos_x86_64.h"
 #undef UPDATE_REGISTER_INFOS_I386_STRUCT_WITH_X86_64_OFFSETS
+    std::vector<lldb_private::RegisterInfo> &shared_regs =
+        GetSharedRegisterInfoVector();
+    shared_regs = g_register_infos;
   }
 
   return &g_register_infos[0];

``````````

</details>


https://github.com/llvm/llvm-project/pull/162890