[lldb][AArch64] Add register field enum information

[DavidSpickett]

This enables XML output for enums and adds enums for 2 fields on AArch64 Linux:

• mte_ctrl.tcf, which controls how tag faults are delivered.
• fpcr.rmode, which sets the rounding mode for floating point operations.

The other one we could do is cpsr.btype, but it is not clear what would be useful here so I'm not including it in this change.

[llvmbot]

@llvm/pr-subscribers-lldb

Author: David Spickett (DavidSpickett)

Changes

This enables XML output for enums and adds enums for 2 fields on AArch64:

• mte_ctrl.tcf, which controls how tag faults are delivered.
• fpcr.rmode, which sets the rounding mode for floating point operations.

The other one we could do is cpsr.btype, but it is not clear what would be useful here so I'm not including it in this change.

---

Full diff: https://github.com/llvm/llvm-project/pull/96887.diff

5 Files Affected:

• (modified) lldb/source/Plugins/Process/Utility/RegisterFlagsLinux_arm64.cpp (+10-3)
• (modified) lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp (+2)
• (modified) lldb/test/API/commands/register/register/register_command/TestRegisters.py (+7-1)
• (modified) lldb/test/API/functionalities/postmortem/elf-core/TestLinuxCore.py (+6-1)
• (modified) lldb/test/API/linux/aarch64/mte_core_file/TestAArch64LinuxMTEMemoryTagCoreFile.py (+10-3)

diff --git a/lldb/source/Plugins/Process/Utility/RegisterFlagsLinux_arm64.cpp b/lldb/source/Plugins/Process/Utility/RegisterFlagsLinux_arm64.cpp
index 8ed75d700f225..1242948bcb89e 100644
--- a/lldb/source/Plugins/Process/Utility/RegisterFlagsLinux_arm64.cpp
+++ b/lldb/source/Plugins/Process/Utility/RegisterFlagsLinux_arm64.cpp
@@ -51,16 +51,23 @@ LinuxArm64RegisterFlags::DetectMTECtrlFields(uint64_t hwcap, uint64_t hwcap2) {
   // Represents the contents of NT_ARM_TAGGED_ADDR_CTRL and the value passed
   // to prctl(PR_TAGGED_ADDR_CTRL...). Fields are derived from the defines
   // used to build the value.
+
+  static const FieldEnum tcf_enum(
+      "tcf_enum",
+      {{0, "TCF_NONE"}, {1, "TCF_SYNC"}, {2, "TCF_ASYNC"}, {3, "TCF_ASYMM"}});
   return {{"TAGS", 3, 18}, // 16 bit bitfield shifted up by PR_MTE_TAG_SHIFT.
-          {"TCF_ASYNC", 2},
-          {"TCF_SYNC", 1},
+          {"TCF", 1, 2, &tcf_enum},
           {"TAGGED_ADDR_ENABLE", 0}};
 }
 
 LinuxArm64RegisterFlags::Fields
 LinuxArm64RegisterFlags::DetectFPCRFields(uint64_t hwcap, uint64_t hwcap2) {
+
+  static const FieldEnum rmode_enum(
+      "rmode_enum", {{0, "RN"}, {1, "RP"}, {2, "RM"}, {3, "RZ"}});
+
   std::vector<RegisterFlags::Field> fpcr_fields{
-      {"AHP", 26}, {"DN", 25}, {"FZ", 24}, {"RMode", 22, 23},
+      {"AHP", 26}, {"DN", 25}, {"FZ", 24}, {"RMode", 22, 23, &rmode_enum},
       // Bits 21-20 are "Stride" which is unused in AArch64 state.
   };
 
diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp
index ae1a77e5be832..08d5f5039d516 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp
@@ -3083,6 +3083,7 @@ GDBRemoteCommunicationServerLLGS::BuildTargetXml() {
   if (registers_count)
     response.IndentMore();
 
+  llvm::StringSet<> field_enums_seen;
   for (int reg_index = 0; reg_index < registers_count; reg_index++) {
     const RegisterInfo *reg_info =
         reg_context.GetRegisterInfoAtIndex(reg_index);
@@ -3096,6 +3097,7 @@ GDBRemoteCommunicationServerLLGS::BuildTargetXml() {
 
     if (reg_info->flags_type) {
       response.IndentMore();
+      reg_info->flags_type->EnumsToXML(response, field_enums_seen);
       reg_info->flags_type->ToXML(response);
       response.IndentLess();
     }
diff --git a/lldb/test/API/commands/register/register/register_command/TestRegisters.py b/lldb/test/API/commands/register/register/register_command/TestRegisters.py
index 5c4f3a4bb374c..921fed1082980 100644
--- a/lldb/test/API/commands/register/register/register_command/TestRegisters.py
+++ b/lldb/test/API/commands/register/register/register_command/TestRegisters.py
@@ -632,7 +632,13 @@ def test_register_read_fields(self):
         self.expect("register read fpsr", substrs=["= (QC = 0, IDC = 0, IXC = 0"])
         # AHP/DN/FZ/RMode always present, others may vary.
         self.expect(
-            "register read fpcr", substrs=["= (AHP = 0, DN = 0, FZ = 0, RMode = 0"]
+            "register read fpcr", substrs=["= (AHP = 0, DN = 0, FZ = 0, RMode = RN"]
+        )
+
+        # Should get enumerator descriptions for RMode.
+        self.expect(
+            "register info fpcr",
+            substrs=["RMode: 0 = RN, 1 = RP, 2 = RM, 3 = RZ"],
         )
 
     @skipUnlessPlatform(["linux"])
diff --git a/lldb/test/API/functionalities/postmortem/elf-core/TestLinuxCore.py b/lldb/test/API/functionalities/postmortem/elf-core/TestLinuxCore.py
index 1eaaa87d3b87d..0afac26367de0 100644
--- a/lldb/test/API/functionalities/postmortem/elf-core/TestLinuxCore.py
+++ b/lldb/test/API/functionalities/postmortem/elf-core/TestLinuxCore.py
@@ -583,7 +583,12 @@ def test_aarch64_sve_regs_full(self):
         self.expect("register read fpsr", substrs=["= (QC = 0, IDC = 0, IXC = 0"])
         # AHP/DN/FZ/RMode always present, others may vary.
         self.expect(
-            "register read fpcr", substrs=["= (AHP = 0, DN = 0, FZ = 0, RMode = 0"]
+            "register read fpcr", substrs=["= (AHP = 0, DN = 0, FZ = 0, RMode = RN"]
+        )
+        # RMode should have enumerator descriptions.
+        self.expect(
+            "register info fpcr",
+            substrs=["RMode: 0 = RN, 1 = RP, 2 = RM, 3 = RZ"],
         )
 
     @skipIfLLVMTargetMissing("AArch64")
diff --git a/lldb/test/API/linux/aarch64/mte_core_file/TestAArch64LinuxMTEMemoryTagCoreFile.py b/lldb/test/API/linux/aarch64/mte_core_file/TestAArch64LinuxMTEMemoryTagCoreFile.py
index 045f8c0a70108..0667759a341b8 100644
--- a/lldb/test/API/linux/aarch64/mte_core_file/TestAArch64LinuxMTEMemoryTagCoreFile.py
+++ b/lldb/test/API/linux/aarch64/mte_core_file/TestAArch64LinuxMTEMemoryTagCoreFile.py
@@ -238,8 +238,15 @@ def test_mte_ctrl_register(self):
         expected = ["mte_ctrl = 0x000000000007fffb"]
 
         if self.hasXMLSupport():
-            expected.append(
-                "(TAGS = 65535, TCF_ASYNC = 0, TCF_SYNC = 1, TAGGED_ADDR_ENABLE = 1)"
-            )
+            expected.append("(TAGS = 65535, TCF = TCF_SYNC, TAGGED_ADDR_ENABLE = 1)")
 
         self.expect("register read mte_ctrl", substrs=expected)
+
+        if self.hasXMLSupport():
+            # Should get enumerator descriptions for TCF
+            self.expect(
+                "register info mte_ctrl",
+                substrs=[
+                    "TCF: 0 = TCF_NONE, 1 = TCF_SYNC, 2 = TCF_ASYNC, 3 = TCF_ASYMM"
+                ],
+            )

[DavidSpickett]

This is in theory the last patch for this series, but depending on #90059 the format might change slightly. So I'm going to add a release note after that's sorted.

[DavidSpickett]

Rebased as FreeBSD support went in yesterday and moved some files about.

[bulbazord]

LGTM, seems like the natural progression of this work. :)

[jasonmolenda]

LGTM.