[RISCV][MC] Mark Zawrs extension as non-experimental

[asb]

Summary

Support for the unratified 1.0-rc3 specification was introduced in D133443. The specification has since been ratified (in November 2022 according to the recently ratified extensions list.

A review of the diff of the 1.0-rc3 spec vs the current/ratified document shows no changes to the instruction encoding or naming. At one point, a note was added indicating Zawrs depends on the Zalrsc extension (not officially specified, but I believe to be just the LR/SC instructions from the A extension). The final text ended up as "The instructions in the Zawrs extension are only useful in conjunction with the LR instructions, which are provided by the A extension, and which we also expect to be provided by a narrower Zalrsc extension in the future." I think it's consistent with this phrasing to not require the A extension for Zawrs, which matches what was implemented.

No intrinsics are implemented for Zawrs currently, meaning we don't need to additionally review whether those intrinsics can be considered finalised and ready for exposure to end users.

[reames]

LGTM

clang/test/Preprocessor/riscv-target-features.c

 // CHECK-ZICBOZ-EXT: __riscv_zicboz 1000000{{$}}
 
 // RUN: %clang -target riscv32 -march=rv32izicbop -x c -E -dM %s \
 // RUN: -o - | FileCheck --check-prefix=CHECK-ZICBOP-EXT %s
 // RUN: %clang -target riscv64 -march=rv64izicbop -x c -E -dM %s \
 // RUN: -o - | FileCheck --check-prefix=CHECK-ZICBOP-EXT %s
 // CHECK-ZICBOP-EXT: __riscv_zicbop 1000000{{$}}
 
-// RUN: %clang -target riscv32-unknown-linux-gnu -menable-experimental-extensions \
-// RUN: -march=rv32izawrs1p0 -x c -E -dM %s \
+// RUN: %clang -target riscv32-unknown-linux-gnu \
+// RUN: -march=rv32izawrs -x c -E -dM %s \
 // RUN: -o - | FileCheck --check-prefix=CHECK-ZAWRS-EXT %s
-// RUN: %clang -target riscv64-unknown-linux-gnu -menable-experimental-extensions \
-// RUN: -march=rv64izawrs1p0 -x c -E -dM %s \
+// RUN: %clang -target riscv64-unknown-linux-gnu \
+// RUN: -march=rv64izawrs -x c -E -dM %s \
 // RUN: -o - | FileCheck --check-prefix=CHECK-ZAWRS-EXT %s
 // CHECK-ZAWRS-EXT: __riscv_zawrs 1000000{{$}}
 
 // RUN: %clang -target riscv32-unknown-linux-gnu -menable-experimental-extensions \
 // RUN: -march=rv32iztso0p1 -x c -E -dM %s \
 // RUN: -o - | FileCheck --check-prefix=CHECK-ZTSO-EXT %s
 // RUN: %clang -target riscv64-unknown-linux-gnu -menable-experimental-extensions \
 // RUN: -march=rv64iztso0p1 -x c -E -dM %s \

llvm/docs/RISCVUsage.rst

.. table:: Ratified Extensions by Status
      ``D``            Supported
      ``F``            Supported
      ``H``            Assembly Support
      ``M``            Supported
      ``Svinval``      Assembly Support
      ``Svnapot``      Assembly Support
      ``Svpbmt``       Supported
      ``V``            Supported
+     ``Zawrs``        Assembly Support
      ``Zba``          Supported
      ``Zbb``          Supported
      ``Zbc``          Supported
      ``Zbkb``         Supported (`See note <#riscv-scalar-crypto-note1>`__)
      ``Zbkc``         Supported
      ``Zbkx``         Supported (`See note <#riscv-scalar-crypto-note1>`__)
      ``Zbs``          Supported
      ``Zdinx``        Assembly Support

 
 Experimental Extensions
 =======================
 
 LLVM supports (to various degrees) a number of experimental extensions.  All experimental extensions have ``experimental-`` as a prefix.  There is explicitly no compatibility promised between versions of the toolchain, and regular users are strongly advised *not* to make use of experimental extensions before they reach ratification.
 
 The primary goal of experimental support is to assist in the process of ratification by providing an existence proof of an implementation, and simplifying efforts to validate the value of a proposed extension against large code bases.  Experimental extensions are expected to either transition to ratified status, or be eventually removed.  The decision on whether to accept an experimental extension is currently done on an entirely case by case basis; if you want to propose one, attending the bi-weekly RISC-V sync-up call is strongly advised.
 
-``experimental-zawrs``
-  LLVM implements the `1.0-rc3 draft specification <https://github.com/riscv/riscv-zawrs/releases/download/V1.0-rc3/Zawrs.pdf>`_.  Note that have been backwards incompatible changes made between release candidates for the 1.0 draft.
-
 ``experimental-zca``
   LLVM implements the `1.0.1 draft specification <https://github.com/riscv/riscv-code-size-reduction/releases/tag/v1.0.1>`_.
 
 ``experimental-zcb``
   LLVM implements the `1.0.1 draft specification <https://github.com/riscv/riscv-code-size-reduction/releases/tag/v1.0.1>`_.
 
 ``experimental-zcd``
   LLVM implements the `1.0.1 draft specification <https://github.com/riscv/riscv-code-size-reduction/releases/tag/v1.0.1>`_.

llvm/docs/ReleaseNotes.rst

 * Assembler support for version 1.0.1 of the Zcb extension was added.
 * Zca, Zcf, and Zcd extensions were upgraded to version 1.0.1.
 * vsetvli intrinsics no longer have side effects. They may now be combined,
   moved, deleted, etc. by optimizations.
 * Adds support for the vendor-defined XTHeadBa (address-generation) extension.
 * Adds support for the vendor-defined XTHeadBb (basic bit-manipulation) extension.
 * Adds support for the vendor-defined XTHeadBs (single-bit) extension.
 * Adds support for the vendor-defined XTHeadMac (multiply-accumulate instructions) extension.
+* Support for the now-ratified Zawrs extension is no longer experimental.
 
 Changes to the WebAssembly Backend
 ----------------------------------
 
 * ...
 
 Changes to the Windows Target
 -----------------------------

llvm/lib/Support/RISCVISAInfo.cpp

static const RISCVSupportedExtension SupportedExtensions[] = {
     {"zve64d", RISCVExtensionVersion{1, 0}},
 
     {"zicbom", RISCVExtensionVersion{1, 0}},
     {"zicboz", RISCVExtensionVersion{1, 0}},
     {"zicbop", RISCVExtensionVersion{1, 0}},
     {"zicsr", RISCVExtensionVersion{2, 0}},
     {"zifencei", RISCVExtensionVersion{2, 0}},
 
+    {"zawrs", RISCVExtensionVersion{1, 0}},
+
     {"svnapot", RISCVExtensionVersion{1, 0}},
     {"svpbmt", RISCVExtensionVersion{1, 0}},
     {"svinval", RISCVExtensionVersion{1, 0}},
 
     // vendor-defined ('X') extensions
     {"xtheadba", RISCVExtensionVersion{1, 0}},
     {"xtheadbb", RISCVExtensionVersion{1, 0}},
     {"xtheadbs", RISCVExtensionVersion{1, 0}},
     {"xtheadmac", RISCVExtensionVersion{1, 0}},
     {"xtheadvdot", RISCVExtensionVersion{1, 0}},
     {"xventanacondops", RISCVExtensionVersion{1, 0}},
 };
 
 static const RISCVSupportedExtension SupportedExperimentalExtensions[] = {
     {"zihintntl", RISCVExtensionVersion{0, 2}},
 
     {"zca", RISCVExtensionVersion{1, 0}},
     {"zcb", RISCVExtensionVersion{1, 0}},
     {"zcd", RISCVExtensionVersion{1, 0}},
     {"zcf", RISCVExtensionVersion{1, 0}},
     {"zfa", RISCVExtensionVersion{0, 1}},
     {"zvfh", RISCVExtensionVersion{0, 1}},
-    {"zawrs", RISCVExtensionVersion{1, 0}},
     {"ztso", RISCVExtensionVersion{0, 1}},
 };
 
 static bool stripExperimentalPrefix(StringRef &Ext) {
   return Ext.consume_front("experimental-");
 }
 
 // This function finds the first character that doesn't belong to a version

llvm/lib/Target/RISCV/RISCVFeatures.td

 
 def FeatureStdExtZtso
     : SubtargetFeature<"experimental-ztso", "HasStdExtZtso", "true",
                        "'Ztso' (Memory Model - Total Store Order)">;
 def HasStdExtZtso : Predicate<"Subtarget->hasStdExtZTso()">,
                               AssemblerPredicate<(all_of FeatureStdExtZtso),
                               "'Ztso' (Memory Model - Total Store Order)">;
 
-def FeatureStdExtZawrs
-    : SubtargetFeature<"experimental-zawrs", "HasStdExtZawrs", "true",
+def FeatureStdExtZawrs : SubtargetFeature<"zawrs", "HasStdExtZawrs", "true",
                                           "'Zawrs' (Wait on Reservation Set)">;
 def HasStdExtZawrs : Predicate<"Subtarget->hasStdExtZawrs()">,
                                AssemblerPredicate<(all_of FeatureStdExtZawrs),
                                "'Zawrs' (Wait on Reservation Set)">;
 
 //===----------------------------------------------------------------------===//
 // Vendor extensions
 //===----------------------------------------------------------------------===//
 

llvm/test/CodeGen/RISCV/attributes.ll

 ; RUN: llc -mtriple=riscv64 -mattr=+svpbmt %s -o - | FileCheck --check-prefixes=CHECK,RV64SVPBMT %s
 ; RUN: llc -mtriple=riscv64 -mattr=+svinval %s -o - | FileCheck --check-prefixes=CHECK,RV64SVINVAL %s
 ; RUN: llc -mtriple=riscv64 -mattr=+xventanacondops %s -o - | FileCheck --check-prefixes=CHECK,RV64XVENTANACONDOPS %s
 ; RUN: llc -mtriple=riscv64 -mattr=+xtheadba %s -o - | FileCheck --check-prefixes=CHECK,RV64XTHEADBA %s
 ; RUN: llc -mtriple=riscv64 -mattr=+xtheadbb %s -o - | FileCheck --check-prefixes=CHECK,RV64XTHEADBB %s
 ; RUN: llc -mtriple=riscv64 -mattr=+xtheadbs %s -o - | FileCheck --check-prefixes=CHECK,RV64XTHEADBS %s
 ; RUN: llc -mtriple=riscv64 -mattr=+xtheadmac %s -o - | FileCheck --check-prefixes=CHECK,RV64XTHEADMAC %s
 ; RUN: llc -mtriple=riscv64 -mattr=+xtheadvdot %s -o - | FileCheck --check-prefixes=CHECK,RV64XTHEADVDOT %s
-; RUN: llc -mtriple=riscv64 -mattr=+experimental-zawrs %s -o - | FileCheck --check-prefixes=CHECK,RV64ZAWRS %s
+; RUN: llc -mtriple=riscv64 -mattr=+zawrs %s -o - | FileCheck --check-prefixes=CHECK,RV64ZAWRS %s
 ; RUN: llc -mtriple=riscv64 -mattr=+experimental-ztso %s -o - | FileCheck --check-prefixes=CHECK,RV64ZTSO %s
 ; RUN: llc -mtriple=riscv64 -mattr=+experimental-zca %s -o - | FileCheck --check-prefixes=CHECK,RV64ZCA %s
 ; RUN: llc -mtriple=riscv64 -mattr=+experimental-zcb %s -o - | FileCheck --check-prefixes=CHECK,RV64ZCB %s
 ; RUN: llc -mtriple=riscv64 -mattr=+experimental-zcd %s -o - | FileCheck --check-prefixes=CHECK,RV64ZCD %s
 ; RUN: llc -mtriple=riscv64 -mattr=+zicsr %s -o - | FileCheck --check-prefixes=CHECK,RV64ZICSR %s
 ; RUN: llc -mtriple=riscv64 -mattr=+zifencei %s -o - | FileCheck --check-prefixes=CHECK,RV64ZIFENCEI %s
 ; RUN: llc -mtriple=riscv64 -mattr=+experimental-zfa %s -o - | FileCheck --check-prefixes=CHECK,RV64ZFA %s
 

llvm/test/MC/RISCV/Zawrs-valid.s

-# RUN: llvm-mc %s -triple=riscv32 -mattr=+experimental-zawrs -riscv-no-aliases -show-encoding \
+# RUN: llvm-mc %s -triple=riscv32 -mattr=+zawrs -riscv-no-aliases -show-encoding \
 # RUN:     | FileCheck -check-prefixes=CHECK-ASM,CHECK-ASM-AND-OBJ %s
-# RUN: llvm-mc %s -triple=riscv64 -mattr=+experimental-zawrs -riscv-no-aliases -show-encoding \
+# RUN: llvm-mc %s -triple=riscv64 -mattr=+zawrs -riscv-no-aliases -show-encoding \
 # RUN:     | FileCheck -check-prefixes=CHECK-ASM,CHECK-ASM-AND-OBJ %s
-# RUN: llvm-mc -filetype=obj -triple=riscv32 -mattr=+experimental-zawrs < %s \
-# RUN:     | llvm-objdump --mattr=+experimental-zawrs -M no-aliases -d -r - \
+# RUN: llvm-mc -filetype=obj -triple=riscv32 -mattr=+zawrs < %s \
+# RUN:     | llvm-objdump --mattr=+zawrs -M no-aliases -d -r - \
 # RUN:     | FileCheck --check-prefix=CHECK-ASM-AND-OBJ %s
-# RUN: llvm-mc -filetype=obj -triple=riscv64 -mattr=+experimental-zawrs < %s \
-# RUN:     | llvm-objdump --mattr=+experimental-zawrs -M no-aliases -d -r - \
+# RUN: llvm-mc -filetype=obj -triple=riscv64 -mattr=+zawrs < %s \
+# RUN:     | llvm-objdump --mattr=+zawrs -M no-aliases -d -r - \
 # RUN:     | FileCheck --check-prefix=CHECK-ASM-AND-OBJ %s
 
 # CHECK-ASM-AND-OBJ: wrs.nto
 # CHECK-ASM: encoding: [0x73,0x00,0xd0,0x00]
 wrs.nto
 
 # CHECK-ASM-AND-OBJ: wrs.sto
 # CHECK-ASM: encoding: [0x73,0x00,0xd0,0x01]
 wrs.sto