[lldb] Move register info "augmentation" from gdb-remote into ABI

Summary:
Previously the ABI plugin exposed some "register infos" and the
gdb-remote code used those to fill in the missing bits. Now, the
"filling in" code is in the ABI plugin itself, and the gdb-remote code
just invokes that.

The motivation for this is two-fold:
a) the "augmentation" logic is useful outside of process gdb-remote. For
  instance, it would allow us to avoid repeating the register number
  definitions in minidump code.
b) It gives more implementation freedom to the ABI classes. Now that
  these "register infos" are essentially implementation details, classes
  can use other methods to obtain dwarf/eh_frame register numbers -- for
  instance they can consult llvm MC layer.

Since the augmentation code was not currently tested anywhere, I took
the opportunity to create a simple test for it.

Reviewers: jasonmolenda, clayborg, tatyana-krasnukha

Subscribers: aprantl, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D70906

1 files changed, 6 insertions, 34 deletions

diff --git a/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp b/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
index 5d1dd79c2ff..dfef06aa6ea 100644
--- a/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
@@ -388,36 +388,6 @@ bool ProcessGDBRemote::ParsePythonTargetDefinition(
   return false;
 }
 
-// If the remote stub didn't give us eh_frame or DWARF register numbers for a
-// register, see if the ABI can provide them.
-// DWARF and eh_frame register numbers are defined as a part of the ABI.
-static void AugmentRegisterInfoViaABI(RegisterInfo &reg_info,
-                                      ConstString reg_name, ABISP abi_sp) {
-  if (reg_info.kinds[eRegisterKindEHFrame] == LLDB_INVALID_REGNUM ||
-      reg_info.kinds[eRegisterKindDWARF] == LLDB_INVALID_REGNUM) {
-    if (abi_sp) {
-      RegisterInfo abi_reg_info;
-      if (abi_sp->GetRegisterInfoByName(reg_name, abi_reg_info)) {
-        if (reg_info.kinds[eRegisterKindEHFrame] == LLDB_INVALID_REGNUM &&
-            abi_reg_info.kinds[eRegisterKindEHFrame] != LLDB_INVALID_REGNUM) {
-          reg_info.kinds[eRegisterKindEHFrame] =
-              abi_reg_info.kinds[eRegisterKindEHFrame];
-        }
-        if (reg_info.kinds[eRegisterKindDWARF] == LLDB_INVALID_REGNUM &&
-            abi_reg_info.kinds[eRegisterKindDWARF] != LLDB_INVALID_REGNUM) {
-          reg_info.kinds[eRegisterKindDWARF] =
-              abi_reg_info.kinds[eRegisterKindDWARF];
-        }
-        if (reg_info.kinds[eRegisterKindGeneric] == LLDB_INVALID_REGNUM &&
-            abi_reg_info.kinds[eRegisterKindGeneric] != LLDB_INVALID_REGNUM) {
-          reg_info.kinds[eRegisterKindGeneric] =
-              abi_reg_info.kinds[eRegisterKindGeneric];
-        }
-      }
-    }
-  }
-}
-
 static size_t SplitCommaSeparatedRegisterNumberString(
     const llvm::StringRef &comma_separated_regiter_numbers,
     std::vector<uint32_t> &regnums, int base) {
@@ -615,12 +585,12 @@ void ProcessGDBRemote::BuildDynamicRegisterInfo(bool force) {
           reg_info.invalidate_regs = invalidate_regs.data();
         }
 
+        reg_info.name = reg_name.AsCString();
         // We have to make a temporary ABI here, and not use the GetABI because
         // this code gets called in DidAttach, when the target architecture
         // (and consequently the ABI we'll get from the process) may be wrong.
-        ABISP abi_to_use = ABI::FindPlugin(shared_from_this(), arch_to_use);
-
-        AugmentRegisterInfoViaABI(reg_info, reg_name, abi_to_use);
+        if (ABISP abi_sp = ABI::FindPlugin(shared_from_this(), arch_to_use))
+          abi_sp->AugmentRegisterInfo(reg_info);
 
         m_register_info.AddRegister(reg_info, reg_name, alt_name, set_name);
       } else {
@@ -4483,7 +4453,9 @@ bool ParseRegisters(XMLNode feature_node, GdbServerTargetInfo &target_info,
         }
 
         ++cur_reg_num;
-        AugmentRegisterInfoViaABI(reg_info, reg_name, abi_sp);
+        reg_info.name = reg_name.AsCString();
+        if (abi_sp)
+          abi_sp->AugmentRegisterInfo(reg_info);
         dyn_reg_info.AddRegister(reg_info, reg_name, alt_name, set_name);
 
         return true; // Keep iterating through all "reg" elements