[Lldb-commits] [lldb] b0060c3 - [lldb] Make comparing RegisterInfo::[alt_]name's pointer value less footy-shooty

[Raphael Isemann via lldb-commits]

Author: Raphael Isemann
Date: 2020-02-19T13:19:41+01:00
New Revision: b0060c3a7868ef026d95d0cf8a076791ef74f474

URL: https://github.com/llvm/llvm-project/commit/b0060c3a7868ef026d95d0cf8a076791ef74f474
DIFF: https://github.com/llvm/llvm-project/commit/b0060c3a7868ef026d95d0cf8a076791ef74f474.diff

LOG: [lldb] Make comparing RegisterInfo::[alt_]name's pointer value less footy-shooty

Comparing those two `const char *` values relies on the assumption that both
strings were created by a ConstString. Let's check that assumption with an
assert as otherwise this code silently does nothing and that's not great.

Added: 
    

Modified: 
    lldb/source/Plugins/Process/Utility/DynamicRegisterInfo.cpp
    lldb/source/Target/ABI.cpp

Removed: 
    


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diff  --git a/lldb/source/Plugins/Process/Utility/DynamicRegisterInfo.cpp b/lldb/source/Plugins/Process/Utility/DynamicRegisterInfo.cpp
index 3675724deb36..443638aa39f6 100644
--- a/lldb/source/Plugins/Process/Utility/DynamicRegisterInfo.cpp
+++ b/lldb/source/Plugins/Process/Utility/DynamicRegisterInfo.cpp
@@ -742,6 +742,8 @@ const lldb_private::RegisterInfo *DynamicRegisterInfo::GetRegisterInfo(
   for (auto &reg_info : m_regs) {
     // We can use pointer comparison since we used a ConstString to set the
     // "name" member in AddRegister()
+    assert(ConstString(reg_info.name).GetCString() == reg_info.name &&
+           "reg_info.name not from a ConstString?");
     if (reg_info.name == reg_name.GetCString()) {
       return &reg_info;
     }

diff  --git a/lldb/source/Target/ABI.cpp b/lldb/source/Target/ABI.cpp
index 47a46f401e61..cb7eca280a39 100644
--- a/lldb/source/Target/ABI.cpp
+++ b/lldb/source/Target/ABI.cpp
@@ -49,13 +49,20 @@ bool RegInfoBasedABI::GetRegisterInfoByName(ConstString name, RegisterInfo &info
     const char *unique_name_cstr = name.GetCString();
     uint32_t i;
     for (i = 0; i < count; ++i) {
-      if (register_info_array[i].name == unique_name_cstr) {
+      const char *reg_name = register_info_array[i].name;
+      assert(ConstString(reg_name).GetCString() == reg_name &&
+             "register_info_array[i].name not from a ConstString?");
+      if (reg_name == unique_name_cstr) {
         info = register_info_array[i];
         return true;
       }
     }
     for (i = 0; i < count; ++i) {
-      if (register_info_array[i].alt_name == unique_name_cstr) {
+      const char *reg_alt_name = register_info_array[i].alt_name;
+      assert((reg_alt_name == nullptr ||
+              ConstString(reg_alt_name).GetCString() == reg_alt_name) &&
+             "register_info_array[i].alt_name not from a ConstString?");
+      if (reg_alt_name == unique_name_cstr) {
         info = register_info_array[i];
         return true;
       }