[RISCV] Add B extension

It seems that we have `B` extension again: https://github.com/riscv/riscv-b

According to the spec, `B` extension represents the collection of
the `Zba`, `Zbb`, `Zbs` extensions.

Though it hasn't been ratified, I set its version to `1.0`.

Author: wangpc-pp

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

@@ -5,6 +5,7 @@
 
 // CHECK-NOT: __riscv_a {{.*$}}
 // CHECK-NOT: __riscv_atomic
+// CHECK-NOT: __riscv_b {{.*$}}
 // CHECK-NOT: __riscv_c {{.*$}}
 // CHECK-NOT: __riscv_compressed {{.*$}}
 // CHECK-NOT: __riscv_d {{.*$}}
@@ -150,6 +151,17 @@
 // CHECK-A-EXT: __riscv_a 2001000{{$}}
 // CHECK-A-EXT: __riscv_atomic 1
 
+// RUN: %clang --target=riscv32-unknown-linux-gnu \
+// RUN: -march=rv32ib -x c -E -dM %s \
+// RUN: -o - | FileCheck --check-prefix=CHECK-B-EXT %s
+// RUN: %clang --target=riscv64-unknown-linux-gnu \
+// RUN: -march=rv64ib -x c -E -dM %s \
+// RUN: -o - | FileCheck --check-prefix=CHECK-B-EXT %s
+// CHECK-B-EXT: __riscv_b 1000000{{$}}
+// CHECK-B-EXT: __riscv_zba 1000000{{$}}
+// CHECK-B-EXT: __riscv_zbb 1000000{{$}}
+// CHECK-B-EXT: __riscv_zbs 1000000{{$}}
+
 // RUN: %clang --target=riscv32-unknown-linux-gnu \
 // RUN: -march=rv32ic -x c -E -dM %s \
 // RUN: -o - | FileCheck --check-prefix=CHECK-C-EXT %s

llvm/docs/RISCVUsage.rst

@@ -85,6 +85,7 @@ on support follow.
      Extension        Status
      ===============  =========================================================
      ``A``            Supported
+     ``B``            Supported
      ``C``            Supported
      ``D``            Supported
      ``F``            Supported

llvm/lib/Support/RISCVISAInfo.cpp

@@ -51,6 +51,7 @@ static const char *RISCVGImplications[] = {
 // NOTE: This table should be sorted alphabetically by extension name.
 static const RISCVSupportedExtension SupportedExtensions[] = {
     {"a", RISCVExtensionVersion{2, 1}},
+    {"b", RISCVExtensionVersion{1, 0}},
     {"c", RISCVExtensionVersion{2, 0}},
     {"d", RISCVExtensionVersion{2, 2}},
     {"e", RISCVExtensionVersion{2, 0}},
@@ -997,6 +998,7 @@ Error RISCVISAInfo::checkDependency() {
   return Error::success();
 }
 
+static const char *ImpliedExtsB[] = {"zba", "zbb", "zbs"};
 static const char *ImpliedExtsD[] = {"f"};
 static const char *ImpliedExtsF[] = {"zicsr"};
 static const char *ImpliedExtsV[] = {"zvl128b", "zve64d"};
@@ -1071,6 +1073,7 @@ struct ImpliedExtsEntry {
 
 // Note: The table needs to be sorted by name.
 static constexpr ImpliedExtsEntry ImpliedExts[] = {
+    {{"b"}, {ImpliedExtsB}},
     {{"d"}, {ImpliedExtsD}},
     {{"f"}, {ImpliedExtsF}},
     {{"v"}, {ImpliedExtsV}},

llvm/lib/Target/RISCV/RISCVFeatures.td

@@ -202,6 +202,14 @@ def HasStdExtZbs : Predicate<"Subtarget->hasStdExtZbs()">,
                              AssemblerPredicate<(all_of FeatureStdExtZbs),
                              "'Zbs' (Single-Bit Instructions)">;
 
+def FeatureStdExtB
+    : SubtargetFeature<"b", "HasStdExtB", "true",
+                       "'B' (the collection of the Zba, Zbb, Zbs extensions)",
+                       [FeatureStdExtZba, FeatureStdExtZbb, FeatureStdExtZbs]>;
+def HasStdExtB : Predicate<"Subtarget->hasStdExtB()">,
+                           AssemblerPredicate<(all_of FeatureStdExtB),
+                           "'B' (the collection of the Zba, Zbb, Zbs extensions)">;
+
 def FeatureStdExtZbkb
     : SubtargetFeature<"zbkb", "HasStdExtZbkb", "true",
                        "'Zbkb' (Bitmanip instructions for Cryptography)">;

llvm/test/CodeGen/RISCV/attributes.ll

@@ -5,6 +5,7 @@
 ; RUN: llc -mtriple=riscv32 -mattr=+zmmul %s -o - | FileCheck --check-prefixes=CHECK,RV32ZMMUL %s
 ; RUN: llc -mtriple=riscv32 -mattr=+m,+zmmul %s -o - | FileCheck --check-prefixes=CHECK,RV32MZMMUL %s
 ; RUN: llc -mtriple=riscv32 -mattr=+a %s -o - | FileCheck --check-prefixes=CHECK,RV32A %s
+; RUN: llc -mtriple=riscv32 -mattr=+b %s -o - | FileCheck --check-prefixes=CHECK,RV32B %s
 ; RUN: llc -mtriple=riscv32 -mattr=+f %s -o - | FileCheck --check-prefixes=CHECK,RV32F %s
 ; RUN: llc -mtriple=riscv32 -mattr=+d %s -o - | FileCheck --check-prefixes=CHECK,RV32D %s
 ; RUN: llc -mtriple=riscv32 -mattr=+c %s -o - | FileCheck --check-prefixes=CHECK,RV32C %s
@@ -100,6 +101,7 @@
 ; RUN: llc -mtriple=riscv64 -mattr=+zmmul %s -o - | FileCheck --check-prefixes=CHECK,RV64ZMMUL %s
 ; RUN: llc -mtriple=riscv64 -mattr=+m,+zmmul %s -o - | FileCheck --check-prefixes=CHECK,RV64MZMMUL %s
 ; RUN: llc -mtriple=riscv64 -mattr=+a %s -o - | FileCheck --check-prefixes=CHECK,RV64A %s
+; RUN: llc -mtriple=riscv64 -mattr=+b %s -o - | FileCheck --check-prefixes=CHECK,RV64B %s
 ; RUN: llc -mtriple=riscv64 -mattr=+f %s -o - | FileCheck --check-prefixes=CHECK,RV64F %s
 ; RUN: llc -mtriple=riscv64 -mattr=+d %s -o - | FileCheck --check-prefixes=CHECK,RV64D %s
 ; RUN: llc -mtriple=riscv64 -mattr=+c %s -o - | FileCheck --check-prefixes=CHECK,RV64C %s
@@ -195,6 +197,7 @@
 ; RV32ZMMUL: .attribute 5, "rv32i2p1_zmmul1p0"
 ; RV32MZMMUL: .attribute 5, "rv32i2p1_m2p0_zmmul1p0"
 ; RV32A: .attribute 5, "rv32i2p1_a2p1"
+; RV32B: .attribute 5, "rv32i2p1_b1p0_zba1p0_zbb1p0_zbs1p0"
 ; RV32F: .attribute 5, "rv32i2p1_f2p2_zicsr2p0"
 ; RV32D: .attribute 5, "rv32i2p1_f2p2_d2p2_zicsr2p0"
 ; RV32C: .attribute 5, "rv32i2p1_c2p0"
@@ -289,6 +292,7 @@
 ; RV64ZMMUL: .attribute 5, "rv64i2p1_zmmul1p0"
 ; RV64MZMMUL: .attribute 5, "rv64i2p1_m2p0_zmmul1p0"
 ; RV64A: .attribute 5, "rv64i2p1_a2p1"
+; RV64B: .attribute 5, "rv64i2p1_b1p0_zba1p0_zbb1p0_zbs1p0"
 ; RV64F: .attribute 5, "rv64i2p1_f2p2_zicsr2p0"
 ; RV64D: .attribute 5, "rv64i2p1_f2p2_d2p2_zicsr2p0"
 ; RV64C: .attribute 5, "rv64i2p1_c2p0"