[llvm] [ARM] Migrate from SearachableTable to GenericTable. NFC (PR #121840)

[Craig Topper via llvm-commits]

https://github.com/topperc created https://github.com/llvm/llvm-project/pull/121840

SearchableTable is the legacy version that does not appear to be well documented. Not sure if the plan was to delete it eventually.

The enum from SearchableTable does not appear to be used so I did not add a GenericEnum. MClassSysReg assigned EnumValueField 3 times, but rather than creating 3 enums, this overwrites the previous assignment.

We can eventually use the PrimaryKey feature of GenericTable to remove one of the SearchIndex declarations. This will sort the generated table by the primary key and remove the separately generated indexing table to reduce .rodata size.

This patch is just the mechanical migration. The size savings will be done in follow ups.

>From 7e4571a79603e4400990d6e7a7102b5782d94bc4 Mon Sep 17 00:00:00 2001
From: Craig Topper <craig.topper at sifive.com>
Date: Mon, 6 Jan 2025 13:25:18 -0800
Subject: [PATCH] [ARM] Migrate from SearachableTable to GenericTable. NFC

SearchableTable is the legacy version that does not appear to be well
documented. Not sure if the plan was to delete it eventually.

The enum from SearchableTable does not appear to be used so I did not
add a GenericEnum. MClassSysReg assigned EnumValueField 3 times. Rather
than creating 3 enums this just overwrites the previous assignment.

We can eventually use the PrimaryKey feature of GenericTable to remove
one of the SearchIndex declarations. This will sort the generated table
by the primary key and remove the separately generated indexing table to
reduce .rodata size.

This patch is just the mechanical migration. The size savings will be
done in follow ups.
---
 llvm/lib/Target/ARM/ARMSystemRegister.td  | 46 +++++++++++++++++++----
 llvm/lib/Target/ARM/Utils/ARMBaseInfo.cpp |  4 +-
 llvm/lib/Target/ARM/Utils/ARMBaseInfo.h   |  4 +-
 3 files changed, 42 insertions(+), 12 deletions(-)

diff --git a/llvm/lib/Target/ARM/ARMSystemRegister.td b/llvm/lib/Target/ARM/ARMSystemRegister.td
index c03db15d104111..f6733bd7e67fd9 100644
--- a/llvm/lib/Target/ARM/ARMSystemRegister.td
+++ b/llvm/lib/Target/ARM/ARMSystemRegister.td
@@ -19,17 +19,13 @@ class MClassSysReg<bits<1> UniqMask1,
                    bits<1> UniqMask2,
                    bits<1> UniqMask3,
                    bits<12> Enc12,
-                   string name> : SearchableTable {
-  let SearchableFields = ["Name", "M1Encoding12", "M2M3Encoding8", "Encoding"];
+                   string name> {
   string Name;
   bits<13> M1Encoding12;
   bits<10> M2M3Encoding8;
   bits<12> Encoding;
 
   let Name = name;
-  let EnumValueField = "M1Encoding12";
-  let EnumValueField = "M2M3Encoding8";
-  let EnumValueField = "Encoding";
 
   let M1Encoding12{12}    = UniqMask1;
   let M1Encoding12{11-00} = Enc12;
@@ -41,6 +37,26 @@ class MClassSysReg<bits<1> UniqMask1,
   code Requires           = [{ {} }];
 }
 
+def MClassSysRegsList : GenericTable {
+  let FilterClass = "MClassSysReg";
+  let Fields = ["Name", "M1Encoding12", "M2M3Encoding8", "Encoding", "Requires"];
+}
+
+def lookupMClassSysRegByName : SearchIndex {
+  let Table = MClassSysRegsList;
+  let Key = ["Name"];
+}
+
+def lookupMClassSysRegByM1Encoding12 : SearchIndex {
+  let Table = MClassSysRegsList;
+  let Key = ["M1Encoding12"];
+}
+
+def lookupMClassSysRegByM2M3Encoding8 : SearchIndex {
+  let Table = MClassSysRegsList;
+  let Key = ["M2M3Encoding8"];
+}
+
 // [|i|e|x]apsr_nzcvq has alias [|i|e|x]apsr.
 //                 Mask1 Mask2 Mask3 Enc12, Name
 let Requires = [{ {ARM::FeatureDSP} }] in {
@@ -127,15 +143,29 @@ def : MClassSysReg<0,    0,    1,    0x8a7, "pac_key_u_3_ns">;
 
 // Banked Registers
 //
-class BankedReg<string name,  bits<8> enc>
-               : SearchableTable {
+class BankedReg<string name,  bits<8> enc> {
   string Name;
   bits<8> Encoding;
   let Name = name;
   let Encoding = enc;
-  let SearchableFields = ["Name", "Encoding"];
 }
 
+def BankedRegsList : GenericTable {
+  let FilterClass = "BankedReg";
+  let Fields = ["Name", "Encoding"];
+}
+
+def lookupBankedRegByName : SearchIndex {
+  let Table = BankedRegsList;
+  let Key = ["Name"];
+}
+
+def lookupBankedRegByEncoding : SearchIndex {
+  let Table = BankedRegsList;
+  let Key = ["Encoding"];
+}
+
+
 // The values here come from B9.2.3 of the ARM ARM, where bits 4-0 are SysM
 // and bit 5 is R.
 def : BankedReg<"r8_usr",   0x00>;
diff --git a/llvm/lib/Target/ARM/Utils/ARMBaseInfo.cpp b/llvm/lib/Target/ARM/Utils/ARMBaseInfo.cpp
index 494c67d4b77682..e76a70b3610a82 100644
--- a/llvm/lib/Target/ARM/Utils/ARMBaseInfo.cpp
+++ b/llvm/lib/Target/ARM/Utils/ARMBaseInfo.cpp
@@ -62,13 +62,13 @@ const MClassSysReg *lookupMClassSysRegBy8bitSYSmValue(unsigned SYSm) {
   return ARMSysReg::lookupMClassSysRegByM2M3Encoding8((1<<8)|(SYSm & 0xFF));
 }
 
-#define GET_MCLASSSYSREG_IMPL
+#define GET_MClassSysRegsList_IMPL
 #include "ARMGenSystemRegister.inc"
 
 } // end namespace ARMSysReg
 
 namespace ARMBankedReg {
-#define GET_BANKEDREG_IMPL
+#define GET_BankedRegsList_IMPL
 #include "ARMGenSystemRegister.inc"
 } // end namespce ARMSysReg
 } // end namespace llvm
diff --git a/llvm/lib/Target/ARM/Utils/ARMBaseInfo.h b/llvm/lib/Target/ARM/Utils/ARMBaseInfo.h
index 5562572c5abf48..70bb7058c689c0 100644
--- a/llvm/lib/Target/ARM/Utils/ARMBaseInfo.h
+++ b/llvm/lib/Target/ARM/Utils/ARMBaseInfo.h
@@ -206,7 +206,7 @@ namespace ARMSysReg {
     }
   };
 
-  #define GET_MCLASSSYSREG_DECL
+  #define GET_MClassSysRegsList_DECL
   #include "ARMGenSystemRegister.inc"
 
   // lookup system register using 12-bit SYSm value.
@@ -228,7 +228,7 @@ namespace ARMBankedReg {
     const char *Name;
     uint16_t Encoding;
   };
-  #define GET_BANKEDREG_DECL
+  #define GET_BankedRegsList_DECL
   #include "ARMGenSystemRegister.inc"
 } // end namespace ARMBankedReg