[RISCV] Remove CSR names that are not in Privileged Specification 1.12.

[craig.topper]

Summary

These are from the N extension (User-Level Interrupts) which did
not make it into 1.12 of the Privileged Specification.

D117653 also tried to remove some of these, but it was never reviewed.

[jrtc27]

I can't imagine anyone's actually using N. I would recommend just killing them entirely; the extension has been shelved.

[craig.topper]

Remove the CSR names instead

llvm/docs/ReleaseNotes.rst

 * Changed the ShadowCallStack register from ``x18`` (``s2``) to ``x3``
   (``gp``). Note this breaks the existing non-standard ABI for ShadowCallStack
   on RISC-V, but conforms with the new "platform register" defined in the
   RISC-V psABI (for more details see the 
   `psABI discussion <https://github.com/riscv-non-isa/riscv-elf-psabi-doc/issues/370>`_).
 * Added support for Zfa extension version 0.2.
 * Updated support experimental vector crypto extensions to version 0.5.1 of
   the specification.
+* Deprecated N extension (User-Level Interrupts) CSR names in the assembler.
 
 Changes to the WebAssembly Backend
 ----------------------------------
 
 * ...
 
 Changes to the Windows Target
 -----------------------------

llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp

 //===-- RISCVAsmParser.cpp - Parse RISC-V assembly to MCInst instructions -===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
case AsmToken::Identifier: {
     auto SysReg = RISCVSysReg::lookupSysRegByName(Identifier);
     if (!SysReg)
       SysReg = RISCVSysReg::lookupSysRegByAltName(Identifier);
     if (!SysReg)
       if ((SysReg = RISCVSysReg::lookupSysRegByDeprecatedName(Identifier)))
         Warning(S, "'" + Identifier + "' is a deprecated alias for '" +
                        SysReg->Name + "'");
 
+    if (SysReg && SysReg->isDeprecated)
+      Warning(S, Twine("'") + SysReg->Name + "' is deprecated");
+
     // Accept a named Sys Reg if the required features are present.
     if (SysReg) {
       if (!SysReg->haveRequiredFeatures(getSTI().getFeatureBits())) {
         Error(S, "system register use requires an option to be enabled");
         return MatchOperand_ParseFail;
       }
       Operands.push_back(
           RISCVOperand::createSysReg(Identifier, S, SysReg->Encoding));

llvm/lib/Target/RISCV/MCTargetDesc/RISCVBaseInfo.h

 //===-- RISCVBaseInfo.h - Top level definitions for RISC-V MC ---*- C++ -*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 //
struct SysReg {
   // Privilege Mode: User, System or Machine.
   // unsigned Mode;
   // Check field name.
   // unsigned Extra;
   // Register number without the privilege bits.
   // unsigned Number;
   FeatureBitset FeaturesRequired;
   bool isRV32Only;
+  bool isDeprecated;
 
   bool haveRequiredFeatures(const FeatureBitset &ActiveFeatures) const {
     // Not in 32-bit mode.
     if (isRV32Only && ActiveFeatures[RISCV::Feature64Bit])
       return false;
     // No required feature associated with the system register.
     if (FeaturesRequired.none())
       return true;

llvm/lib/Target/RISCV/RISCVSystemOperands.td

class SysReg<string name, bits<12> op> {
   // bits<2> ReadWrite = op{11 - 10};
   // bits<2> XMode = op{9 - 8};
   // Check Extra field name and what bits 7-6 correspond to.
   // bits<2> Extra = op{7 - 6};
   // Register number without the privilege bits.
   // bits<6> Number = op{5 - 0};
   code FeaturesRequired = [{ {} }];
   bit isRV32Only = 0;
+  bit isDeprecated = 0;
 }
 
 def SysRegsList : GenericTable {
   let FilterClass = "SysReg";
   // FIXME: add "ReadWrite", "Mode", "Extra", "Number" fields when needed.
   let Fields = [
     "Name", "AltName", "DeprecatedName", "Encoding", "FeaturesRequired",
-    "isRV32Only",
+    "isRV32Only", "isDeprecated"
   ];
 
   let PrimaryKey = [ "Encoding" ];
   let PrimaryKeyName = "lookupSysRegByEncoding";
 }
 
 def lookupSysRegByName : SearchIndex {
   let Table = SysRegsList;
   let Key = [ "Name" ];
 }
 
 def lookupSysRegByAltName : SearchIndex {
   let Table = SysRegsList;
   let Key = [ "AltName" ];
 }
 
 def lookupSysRegByDeprecatedName : SearchIndex {
   let Table = SysRegsList;
   let Key = [ "DeprecatedName" ];
 }
 
 // The following CSR encodings match those given in Tables 2.2,
-// 2.3, 2.4 and  2.5 in the RISC-V Instruction Set Manual
+// 2.3, 2.4, 2.5 and 2.6 in the RISC-V Instruction Set Manual
 // Volume II: Privileged Architecture.
 
 //===----------------------------------------------------------------------===//
-// User Trap Setup
+// User Trap Setup (Deprecated)
 //===----------------------------------------------------------------------===//
+let isDeprecated = 1 in {
 def : SysReg<"ustatus", 0x000>;
 def : SysReg<"uie", 0x004>;
 def : SysReg<"utvec", 0x005>;
+} // isDeprecated = 1
 
 //===----------------------------------------------------------------------===//
-// User Trap Handling
+// User Trap Handling (Deprecated)
 //===----------------------------------------------------------------------===//
+let isDeprecated = 1 in {
 def : SysReg<"uscratch", 0x040>;
 def : SysReg<"uepc", 0x041>;
 def : SysReg<"ucause", 0x042>;
 let DeprecatedName = "ubadaddr" in
 def : SysReg<"utval", 0x043>;
 def : SysReg<"uip", 0x044>;
+} // isDeprecated = 1
 
 //===----------------------------------------------------------------------===//
 // User Floating-Point CSRs
 //===----------------------------------------------------------------------===//
 
 def SysRegFFLAGS : SysReg<"fflags", 0x001>;
 def SysRegFRM    : SysReg<"frm", 0x002>;
 def SysRegFCSR   : SysReg<"fcsr", 0x003>;

 foreach i = 3...31 in
   def : SysReg<"hpmcounter"#i#"h", !add(0xC83, !sub(i, 3))>;
 }
 
 //===----------------------------------------------------------------------===//
 // Supervisor Trap Setup
 //===----------------------------------------------------------------------===//
 def : SysReg<"sstatus", 0x100>;
+let isDeprecated = 1 in
 def : SysReg<"sedeleg", 0x102>;
+let isDeprecated = 1 in
 def : SysReg<"sideleg", 0x103>;
 def : SysReg<"sie", 0x104>;
 def : SysReg<"stvec", 0x105>;
 def : SysReg<"scounteren", 0x106>;
 def : SysReg<"stimecmp", 0x14D>;
 let isRV32Only = 1 in
 def : SysReg<"stimecmph", 0x15D>;
 

llvm/test/MC/RISCV/deprecated-csr-names.s

 # CHECK-ENC: encoding: [0x73,0x10,0x30,0x04]
 # CHECK-INST-ALIAS: csrw utval, zero
 # name
 csrw ubadaddr, zero
 # uimm12
 csrrw zero, 0x043, zero
 
 # CHECK-WARN: warning: 'ubadaddr' is a deprecated alias for 'utval'
+# CHECK-WARN: warning: 'utval' is deprecated
 
 # sptbr
 # name
 # CHECK-INST: csrrw zero, satp, zero
 # CHECK-ENC: encoding: [0x73,0x10,0x00,0x18]
 # CHECK-INST-ALIAS: csrw satp, zero
 # uimm12
 # CHECK-INST: csrrw zero, satp, zero
 # CHECK-ENC: encoding: [0x73,0x10,0x00,0x18]
 # CHECK-INST-ALIAS: csrw satp, zero
 # name
 csrw sptbr, zero
 # uimm12
 csrrw zero, 0x180, zero
 
 # CHECK-WARN: warning: 'sptbr' is a deprecated alias for 'satp'
+
+# ustatus
+# name
+# CHECK-INST: csrrs t1, ustatus, zero
+# CHECK-ENC:  encoding: [0x73,0x23,0x00,0x00]
+# CHECK-INST-ALIAS: csrr t1, ustatus
+# uimm12
+# CHECK-INST: csrrs t2, ustatus, zero
+# CHECK-ENC:  encoding: [0xf3,0x23,0x00,0x00]
+# CHECK-INST-ALIAS: csrr t2, ustatus
+csrrs t1, ustatus, zero
+# uimm12
+csrrs t2, 0x000, zero
+
+# CHECK-WARN: warning: 'ustatus' is deprecated
+
+# uie
+# name
+# CHECK-INST: csrrs t1, uie, zero
+# CHECK-ENC:  encoding: [0x73,0x23,0x40,0x00]
+# CHECK-INST-ALIAS: csrr t1, uie
+# uimm12
+# CHECK-INST: csrrs t2, uie, zero
+# CHECK-ENC:  encoding: [0xf3,0x23,0x40,0x00]
+# CHECK-INST-ALIAS: csrr t2, uie
+# name
+csrrs t1, uie, zero
+# uimm12
+csrrs t2, 0x004, zero
+
+# CHECK-WARN: warning: 'uie' is deprecated
+
+# utvec
+# name
+# CHECK-INST: csrrs t1, utvec, zero
+# CHECK-ENC:  encoding: [0x73,0x23,0x50,0x00]
+# CHECK-INST-ALIAS: csrr t1, utvec
+# uimm12
+# CHECK-INST: csrrs t2, utvec, zero
+# CHECK-ENC:  encoding: [0xf3,0x23,0x50,0x00]
+# CHECK-INST-ALIAS: csrr t2, utvec
+# name
+csrrs t1, utvec, zero
+# uimm12
+csrrs t2, 0x005, zero
+
+# CHECK-WARN: warning: 'utvec' is deprecated
+
+# uscratch
+# name
+# CHECK-INST: csrrs t1, uscratch, zero
+# CHECK-ENC:  encoding: [0x73,0x23,0x00,0x04]
+# CHECK-INST-ALIAS: csrr t1, uscratch
+# uimm12
+# CHECK-INST: csrrs t2, uscratch, zero
+# CHECK-ENC:  encoding: [0xf3,0x23,0x00,0x04]
+# CHECK-INST-ALIAS: csrr t2, uscratch
+# name
+csrrs t1, uscratch, zero
+# uimm12
+csrrs t2, 0x040, zero
+
+# CHECK-WARN: warning: 'uscratch' is deprecated
+
+# uepc
+# name
+# CHECK-INST: csrrs t1, uepc, zero
+# CHECK-ENC:  encoding: [0x73,0x23,0x10,0x04]
+# CHECK-INST-ALIAS: csrr t1, uepc
+# uimm12
+# CHECK-INST: csrrs t2, uepc, zero
+# CHECK-ENC:  encoding: [0xf3,0x23,0x10,0x04]
+# CHECK-INST-ALIAS: csrr t2, uepc
+# name
+csrrs t1, uepc, zero
+# uimm12
+csrrs t2, 0x041, zero
+
+# CHECK-WARN: warning: 'uepc' is deprecated
+
+# ucause
+# name
+# CHECK-INST: csrrs t1, ucause, zero
+# CHECK-ENC:  encoding: [0x73,0x23,0x20,0x04]
+# CHECK-INST-ALIAS: csrr t1, ucause
+# uimm12
+# CHECK-INST: csrrs t2, ucause, zero
+# CHECK-ENC:  encoding: [0xf3,0x23,0x20,0x04]
+# CHECK-INST-ALIAS: csrr t2, ucause
+# name
+csrrs t1, ucause, zero
+# uimm12
+csrrs t2, 0x042, zero
+
+# CHECK-WARN: warning: 'ucause' is deprecated
+
+# utval
+# name
+# CHECK-INST: csrrs t1, utval, zero
+# CHECK-ENC:  encoding: [0x73,0x23,0x30,0x04]
+# CHECK-INST-ALIAS: csrr t1, utval
+# uimm12
+# CHECK-INST: csrrs t2, utval, zero
+# CHECK-ENC:  encoding: [0xf3,0x23,0x30,0x04]
+
+csrrs t1, utval, zero
+# uimm12
+csrrs t2, 0x043, zero
+
+# CHECK-WARN: warning: 'utval' is deprecated
+
+# uip
+# name
+# CHECK-INST: csrrs t1, uip, zero
+# CHECK-ENC:  encoding: [0x73,0x23,0x40,0x04]
+# CHECK-INST-ALIAS: csrr t1, uip
+# uimm12
+# CHECK-INST: csrrs t2, uip, zero
+# CHECK-ENC:  encoding: [0xf3,0x23,0x40,0x04]
+# CHECK-INST-ALIAS: csrr t2, uip
+#name
+csrrs t1, uip, zero
+# uimm12
+csrrs t2, 0x044, zero
+
+# CHECK-WARN: warning: 'uip' is deprecated
+
+# sedeleg
+# name
+# CHECK-INST: csrrs t1, sedeleg, zero
+# CHECK-ENC: encoding: [0x73,0x23,0x20,0x10]
+# CHECK-INST-ALIAS: csrr t1, sedeleg
+# uimm12
+# CHECK-INST: csrrs t2, sedeleg, zero
+# CHECK-ENC: encoding: [0xf3,0x23,0x20,0x10]
+# CHECK-INST-ALIAS: csrr t2, sedeleg
+# name
+csrrs t1, sedeleg, zero
+# uimm12
+csrrs t2, 0x102, zero
+
+# CHECK-WARN: warning: 'sedeleg' is deprecated
+
+# sideleg
+# name
+# CHECK-INST: csrrs t1, sideleg, zero
+# CHECK-ENC: encoding: [0x73,0x23,0x30,0x10]
+# CHECK-INST-ALIAS: csrr t1, sideleg
+# uimm12
+# CHECK-INST: csrrs t2, sideleg, zero
+# CHECK-ENC: encoding: [0xf3,0x23,0x30,0x10]
+# CHECK-INST-ALIAS: csrr t2, sideleg
+# name
+csrrs t1, sideleg, zero
+# uimm12
+csrrs t2, 0x103, zero
+
+# CHECK-WARN: warning: 'sideleg' is deprecated

llvm/test/MC/RISCV/supervisor-csr-names.s

 # CHECK-INST: csrrs t2, sstatus, zero
 # CHECK-ENC: encoding: [0xf3,0x23,0x00,0x10]
 # CHECK-INST-ALIAS: csrr t2, sstatus
 # name
 csrrs t1, sstatus, zero
 # uimm12
 csrrs t2, 0x100, zero
 
-# sedeleg
-# name
-# CHECK-INST: csrrs t1, sedeleg, zero
-# CHECK-ENC: encoding: [0x73,0x23,0x20,0x10]
-# CHECK-INST-ALIAS: csrr t1, sedeleg
-# uimm12
-# CHECK-INST: csrrs t2, sedeleg, zero
-# CHECK-ENC: encoding: [0xf3,0x23,0x20,0x10]
-# CHECK-INST-ALIAS: csrr t2, sedeleg
-# name
-csrrs t1, sedeleg, zero
-# uimm12
-csrrs t2, 0x102, zero
-
-# sideleg
-# name
-# CHECK-INST: csrrs t1, sideleg, zero
-# CHECK-ENC: encoding: [0x73,0x23,0x30,0x10]
-# CHECK-INST-ALIAS: csrr t1, sideleg
-# uimm12
-# CHECK-INST: csrrs t2, sideleg, zero
-# CHECK-ENC: encoding: [0xf3,0x23,0x30,0x10]
-# CHECK-INST-ALIAS: csrr t2, sideleg
-# name
-csrrs t1, sideleg, zero
-# uimm12
-csrrs t2, 0x103, zero
-
 # sie
 # name
 # CHECK-INST: csrrs t1, sie, zero
 # CHECK-ENC: [0x73,0x23,0x40,0x10]
 # CHECK-INST-ALIAS: csrr t1, sie
 # uimm12
 # CHECK-INST: csrrs t2, sie, zero
 # CHECK-ENC: encoding: [0xf3,0x23,0x40,0x10]

llvm/test/MC/RISCV/user-csr-names.s

 # RUN: llvm-mc %s -triple=riscv32 -riscv-no-aliases -show-encoding \
 # RUN:     | FileCheck -check-prefixes=CHECK-INST,CHECK-ENC %s
 # RUN: llvm-mc -filetype=obj -triple riscv32 < %s \
 # RUN:     | llvm-objdump -d - \
 # RUN:     | FileCheck -check-prefix=CHECK-INST-ALIAS %s
 #
 # RUN: llvm-mc %s -triple=riscv64 -riscv-no-aliases -show-encoding \
 # RUN:     | FileCheck -check-prefixes=CHECK-INST,CHECK-ENC %s
 # RUN: llvm-mc -filetype=obj -triple riscv64 < %s \
 # RUN:     | llvm-objdump -d - \
 # RUN:     | FileCheck -check-prefix=CHECK-INST-ALIAS %s
 
 ##################################
-# User Trap Setup
-##################################
-
-# ustatus
-# name
-# CHECK-INST: csrrs t1, ustatus, zero
-# CHECK-ENC:  encoding: [0x73,0x23,0x00,0x00]
-# CHECK-INST-ALIAS: csrr t1, ustatus
-# uimm12
-# CHECK-INST: csrrs t2, ustatus, zero
-# CHECK-ENC:  encoding: [0xf3,0x23,0x00,0x00]
-# CHECK-INST-ALIAS: csrr t2, ustatus
-csrrs t1, ustatus, zero
-# uimm12
-csrrs t2, 0x000, zero
-
-# uie
-# name
-# CHECK-INST: csrrs t1, uie, zero
-# CHECK-ENC:  encoding: [0x73,0x23,0x40,0x00]
-# CHECK-INST-ALIAS: csrr t1, uie
-# uimm12
-# CHECK-INST: csrrs t2, uie, zero
-# CHECK-ENC:  encoding: [0xf3,0x23,0x40,0x00]
-# CHECK-INST-ALIAS: csrr t2, uie
-# name
-csrrs t1, uie, zero
-# uimm12
-csrrs t2, 0x004, zero
-
-# utvec
-# name
-# CHECK-INST: csrrs t1, utvec, zero
-# CHECK-ENC:  encoding: [0x73,0x23,0x50,0x00]
-# CHECK-INST-ALIAS: csrr t1, utvec
-# uimm12
-# CHECK-INST: csrrs t2, utvec, zero
-# CHECK-ENC:  encoding: [0xf3,0x23,0x50,0x00]
-# CHECK-INST-ALIAS: csrr t2, utvec
-# name
-csrrs t1, utvec, zero
-# uimm12
-csrrs t2, 0x005, zero
-
-##################################
-# User Trap Handling
-##################################
-
-# uscratch
-# name
-# CHECK-INST: csrrs t1, uscratch, zero
-# CHECK-ENC:  encoding: [0x73,0x23,0x00,0x04]
-# CHECK-INST-ALIAS: csrr t1, uscratch
-# uimm12
-# CHECK-INST: csrrs t2, uscratch, zero
-# CHECK-ENC:  encoding: [0xf3,0x23,0x00,0x04]
-# CHECK-INST-ALIAS: csrr t2, uscratch
-# name
-csrrs t1, uscratch, zero
-# uimm12
-csrrs t2, 0x040, zero
-
-# uepc
-# name
-# CHECK-INST: csrrs t1, uepc, zero
-# CHECK-ENC:  encoding: [0x73,0x23,0x10,0x04]
-# CHECK-INST-ALIAS: csrr t1, uepc
-# uimm12
-# CHECK-INST: csrrs t2, uepc, zero
-# CHECK-ENC:  encoding: [0xf3,0x23,0x10,0x04]
-# CHECK-INST-ALIAS: csrr t2, uepc
-# name
-csrrs t1, uepc, zero
-# uimm12
-csrrs t2, 0x041, zero
-
-# ucause
-# name
-# CHECK-INST: csrrs t1, ucause, zero
-# CHECK-ENC:  encoding: [0x73,0x23,0x20,0x04]
-# CHECK-INST-ALIAS: csrr t1, ucause
-# uimm12
-# CHECK-INST: csrrs t2, ucause, zero
-# CHECK-ENC:  encoding: [0xf3,0x23,0x20,0x04]
-# CHECK-INST-ALIAS: csrr t2, ucause
-# name
-csrrs t1, ucause, zero
-# uimm12
-csrrs t2, 0x042, zero
-
-# utval
-# name
-# CHECK-INST: csrrs t1, utval, zero
-# CHECK-ENC:  encoding: [0x73,0x23,0x30,0x04]
-# CHECK-INST-ALIAS: csrr t1, utval
-# uimm12
-# CHECK-INST: csrrs t2, utval, zero
-# CHECK-ENC:  encoding: [0xf3,0x23,0x30,0x04]
-# CHECK-INST-ALIAS: csrr t2, utval
-# name
-csrrs t1, utval, zero
-# uimm12
-csrrs t2, 0x043, zero
-
-# uip
-# name
-# CHECK-INST: csrrs t1, uip, zero
-# CHECK-ENC:  encoding: [0x73,0x23,0x40,0x04]
-# CHECK-INST-ALIAS: csrr t1, uip
-# uimm12
-# CHECK-INST: csrrs t2, uip, zero
-# CHECK-ENC:  encoding: [0xf3,0x23,0x40,0x04]
-# CHECK-INST-ALIAS: csrr t2, uip
-#name
-csrrs t1, uip, zero
-# uimm12
-csrrs t2, 0x044, zero
-
-##################################
 # User Floating Point CSRs
 ##################################
 # Tests in rvf-user-mode-csr.s
 
 ##################################
 # User Counter and Timers
 ##################################