[RISCV][MC] Add support for experimental Zawrs extension

This implements experimental support for the Zawrs extension as specified here: https://github.com/riscv/riscv-zawrs/releases/download/V1.0-rc3/Zawrs.pdf. Despite the 1.0 version name, this has not been ratified and there was a major change to proposed specification between rc2 and rc3.  Once this is ratified, it'll move out of experimental status.

This change adds assembly support, but does not include C language or IR intrinsics. We can decide if we want them, and handle that in a separate patch.

Differential Revision: https://reviews.llvm.org/D133443

diff --git a/clang/test/Preprocessor/riscv-target-features.c b/clang/test/Preprocessor/riscv-target-features.c
index 9ec9117..39ab684 100644 (file)
--- a/clang/test/Preprocessor/riscv-target-features.c
+++ b/clang/test/Preprocessor/riscv-target-features.c
@@ -464,6 +464,14 @@
 // 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: -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: -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 \

diff --git a/llvm/docs/RISCVUsage.rst b/llvm/docs/RISCVUsage.rst
index ddfea5b..5db374c 100644 (file)
--- a/llvm/docs/RISCVUsage.rst
+++ b/llvm/docs/RISCVUsage.rst
@@ -128,6 +128,9 @@ LLVM supports (to various degrees) a number of experimental extensions.  All exp
 
 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-zbe``, ``experimental-zbf``, ``experimental-zbm``, ``experimental-zbp``, ``experimental-zbr``, ``experimental-zbt``
   LLVM implements the `latest state of the bitmanip working branch <https://github.com/riscv/riscv-bitmanip/tree/main-history>`_, which is largely similar to the 0.93 draft specification but with some instruction naming changes.  These are individual portions of the bitmanip efforts which did *not* get ratified.  Given ratification for these sub-extensions appears stalled; they are a likely candidate for removal in the future.
 

diff --git a/llvm/lib/Support/RISCVISAInfo.cpp b/llvm/lib/Support/RISCVISAInfo.cpp
index 8deedfb..a9ae607 100644 (file)
--- a/llvm/lib/Support/RISCVISAInfo.cpp
+++ b/llvm/lib/Support/RISCVISAInfo.cpp
@@ -114,6 +114,7 @@ static const RISCVSupportedExtension SupportedExperimentalExtensions[] = {
     {"zbt", RISCVExtensionVersion{0, 93}},
     {"zca", RISCVExtensionVersion{0, 70}},
     {"zvfh", RISCVExtensionVersion{0, 1}},
+    {"zawrs", RISCVExtensionVersion{1, 0}},
     {"ztso", RISCVExtensionVersion{0, 1}},
 };
 

diff --git a/llvm/lib/Target/RISCV/RISCV.td b/llvm/lib/Target/RISCV/RISCV.td
index b4f3416..5ce40e0 100644 (file)
--- a/llvm/lib/Target/RISCV/RISCV.td
+++ b/llvm/lib/Target/RISCV/RISCV.td
@@ -461,6 +461,13 @@ def HasStdExtZtso : Predicate<"Subtarget->hasStdExtZTso()">,
                            AssemblerPredicate<(all_of FeatureStdExtZtso),
                            "'Ztso' (Memory Model - Total Store Order)">;
 
+def FeatureStdExtZawrs
+    : SubtargetFeature<"experimental-zawrs", "HasStdExtZawrs", "true",
+                       "'Zawrs' (Wait on Reservation Set)">;
+def HasStdExtZawrs : Predicate<"Subtarget->hasStdExtZawrs()">,
+                           AssemblerPredicate<(all_of FeatureStdExtZawrs),
+                           "'Zawrs' (Wait on Reservation Set)">;
+
 // Feature32Bit exists to mark CPUs that support RV32 to distinquish them from
 // tuning CPU names.
 def Feature32Bit

diff --git a/llvm/lib/Target/RISCV/RISCVInstrInfo.td b/llvm/lib/Target/RISCV/RISCVInstrInfo.td
index be42044..0b56d47 100644 (file)
--- a/llvm/lib/Target/RISCV/RISCVInstrInfo.td
+++ b/llvm/lib/Target/RISCV/RISCVInstrInfo.td
@@ -705,6 +705,23 @@ def UNIMP : RVInstI<0b001, OPC_SYSTEM, (outs), (ins), "unimp", "">,
   let rd = 0;
   let imm12 = 0b110000000000;
 }
+
+let Predicates = [HasStdExtZawrs] in {
+def WRS_NTO : RVInstI<0b000, OPC_SYSTEM, (outs), (ins), "wrs.nto", "">,
+              Sched<[]> {
+  let rs1 = 0;
+  let rd = 0;
+  let imm12 = 0b000000001101;
+}
+
+def WRS_STO : RVInstI<0b000, OPC_SYSTEM, (outs), (ins), "wrs.sto", "">,
+              Sched<[]> {
+  let rs1 = 0;
+  let rd = 0;
+  let imm12 = 0b000000011101;
+}
+} // Predicates = [HasStdExtZawrs]
+
 } // hasSideEffects = 1, mayLoad = 0, mayStore = 0
 
 def CSRRW : CSR_ir<0b001, "csrrw">;

diff --git a/llvm/lib/Target/RISCV/RISCVSubtarget.h b/llvm/lib/Target/RISCV/RISCVSubtarget.h
index 3c95e06..01c50ad 100644 (file)
--- a/llvm/lib/Target/RISCV/RISCVSubtarget.h
+++ b/llvm/lib/Target/RISCV/RISCVSubtarget.h
@@ -92,6 +92,7 @@ private:
   bool HasStdExtZicboz = false;
   bool HasStdExtZicbop = false;
   bool HasStdExtZmmul = false;
+  bool HasStdExtZawrs = false;
   bool HasStdExtZtso = false;
   bool HasRV32 = false;
   bool HasRV64 = false;
@@ -192,6 +193,7 @@ public:
   bool hasStdExtZicbom() const { return HasStdExtZicbom; }
   bool hasStdExtZicboz() const { return HasStdExtZicboz; }
   bool hasStdExtZicbop() const { return HasStdExtZicbop; }
+  bool hasStdExtZawrs() const { return HasStdExtZawrs; }
   bool hasStdExtZmmul() const { return HasStdExtZmmul; }
   bool hasStdExtZtso() const { return HasStdExtZtso; }
   bool is64Bit() const { return HasRV64; }

diff --git a/llvm/test/CodeGen/RISCV/attributes.ll b/llvm/test/CodeGen/RISCV/attributes.ll
index 88921ee..819dda6 100644 (file)
--- a/llvm/test/CodeGen/RISCV/attributes.ll
+++ b/llvm/test/CodeGen/RISCV/attributes.ll
@@ -84,6 +84,7 @@
 ; RUN: llc -mtriple=riscv64 -mattr=+zicbom %s -o - | FileCheck --check-prefix=RV64ZICBOM %s
 ; RUN: llc -mtriple=riscv64 -mattr=+zicboz %s -o - | FileCheck --check-prefix=RV64ZICBOZ %s
 ; RUN: llc -mtriple=riscv64 -mattr=+zicbop %s -o - | FileCheck --check-prefix=RV64ZICBOP %s
+; RUN: llc -mtriple=riscv64 -mattr=+experimental-zawrs %s -o - | FileCheck --check-prefix=RV64ZAWRS %s
 ; RUN: llc -mtriple=riscv64 -mattr=+experimental-ztso %s -o - | FileCheck --check-prefix=RV64ZTSO %s
 
 ; RV32M: .attribute 5, "rv32i2p0_m2p0"
@@ -170,6 +171,7 @@
 ; RV64COMBINEINTOZKS: .attribute 5, "rv64i2p0_zbkb1p0_zbkc1p0_zbkx1p0_zks1p0_zksed1p0_zksh1p0"
 ; RV64ZICBOM: .attribute 5, "rv64i2p0_zicbom1p0"
 ; RV64ZICBOZ: .attribute 5, "rv64i2p0_zicboz1p0"
+; RV64ZAWRS: .attribute 5, "rv64i2p0_zawrs1p0"
 ; RV64ZICBOP: .attribute 5, "rv64i2p0_zicbop1p0"
 ; RV64ZTSO: .attribute 5, "rv64i2p0_ztso0p1"
 

diff --git a/llvm/test/MC/RISCV/Zawrs-valid.s b/llvm/test/MC/RISCV/Zawrs-valid.s
new file mode 100644 (file)
index 0000000..6ce37a9
--- /dev/null
+++ b/llvm/test/MC/RISCV/Zawrs-valid.s
@@ -0,0 +1,18 @@
+# RUN: llvm-mc %s -triple=riscv32 -mattr=+experimental-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:     | 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:     | 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:     | 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

diff --git a/llvm/test/MC/RISCV/attribute-arch.s b/llvm/test/MC/RISCV/attribute-arch.s
index 3ad7f1d..f6d0d7c 100644 (file)
--- a/llvm/test/MC/RISCV/attribute-arch.s
+++ b/llvm/test/MC/RISCV/attribute-arch.s
@@ -197,5 +197,8 @@
 .attribute arch, "rv32izca0p70"
 # CHECK: attribute      5, "rv32i2p0_zca0p70"
 
+.attribute arch, "rv32izawrs1p0"
+# CHECK: attribute      5, "rv32i2p0_zawrs1p0"
+
 .attribute arch, "rv32iztso0p1"
 # CHECK: attribute      5, "rv32i2p0_ztso0p1"