[RISCV] Lazily add RVV C intrinsics.

Leverage the method OpenCL uses that adds C intrinsics when the lookup
failed. There is no need to define C intrinsics in the header file any
more. It could help to avoid the large header file to speed up the
compilation of RVV source code. Besides that, only the C intrinsics used
by the users will be added into the declaration table.

This patch is based on https://reviews.llvm.org/D103228 and inspired by
OpenCL implementation.

### Experimental Results

#### TL;DR:

- Binary size of clang increase ~200k, which is +0.07%  for debug build and +0.13% for release build.
- Single file compilation speed up ~33x for debug build and ~8.5x for release build
- Regression time reduce ~10% (`ninja check-all`, enable all targets)

#### Header size change
```
       |      size |     LoC |
------------------------------
Before | 4,434,725 |  69,749 |
After  |     6,140 |     162 |
```

#### Single File Compilation Time
Testcase:
```
#include <riscv_vector.h>

vint32m1_t test_vadd_vv_vfloat32m1_t(vint32m1_t op1, vint32m1_t op2, size_t vl) {
  return vadd(op1, op2, vl);
}
```
##### Debug build:
Before:
```
real    0m19.352s
user    0m19.252s
sys     0m0.092s
```

After:
```
real    0m0.576s
user    0m0.552s
sys     0m0.024s
```

~33x speed up for debug build

##### Release build:
Before:
```
real    0m0.773s
user    0m0.741s
sys     0m0.032s
```

After:
```
real    0m0.092s
user    0m0.080s
sys     0m0.012s
```

~8.5x speed up for release build

#### Regression time
Note: the failed case is `tools/llvm-debuginfod-find/debuginfod.test` which is unrelated to this patch.

##### Debug build
Before:
```
Testing Time: 1358.38s
  Skipped          :    11
  Unsupported      :   446
  Passed           : 75767
  Expectedly Failed:   190
  Failed           :     1
```
After
```
Testing Time: 1220.29s
  Skipped          :    11
  Unsupported      :   446
  Passed           : 75767
  Expectedly Failed:   190
  Failed           :     1
```
##### Release build
Before:
```
Testing Time: 381.98s
  Skipped          :    12
  Unsupported      :  1407
  Passed           : 74765
  Expectedly Failed:   176
  Failed           :     1
```
After:
```
Testing Time: 346.25s
  Skipped          :    12
  Unsupported      :  1407
  Passed           : 74765
  Expectedly Failed:   176
  Failed           :     1
```

#### Binary size of clang

##### Debug build
Before
```
   text    data     bss     dec     hex filename
335261851       12726004         552812 348540667       14c64efb        bin/clang
```
After
```
   text    data     bss     dec     hex filename
335442803       12798708         552940 348794451       14ca2e53        bin/clang
```
+253K, +0.07% code size

##### Release build
Before
```
   text    data     bss     dec     hex filename
144123975       8374648  483140 152981763       91e5103 bin/clang
```
After
```
   text    data     bss     dec     hex filename
144255762       8447296  483268 153186326       9217016 bin/clang
```
+204K, +0.13%

Authored-by: Kito Cheng <kito.cheng@sifive.com>
Co-Authored-by: Hsiangkai Wang <kai.wang@sifive.com>

Reviewed By: khchen, aaron.ballman

Differential Revision: https://reviews.llvm.org/D111617

6 files changed, 127 insertions, 21 deletions

diff --git a/clang/include/clang/Basic/CMakeLists.txt b/clang/include/clang/Basic/CMakeLists.txt
index 8cd8913..b930842 100644
--- a/clang/include/clang/Basic/CMakeLists.txt
+++ b/clang/include/clang/Basic/CMakeLists.txt
@@ -90,3 +90,6 @@ clang_tablegen(riscv_vector_builtins.inc -gen-riscv-vector-builtins
 clang_tablegen(riscv_vector_builtin_cg.inc -gen-riscv-vector-builtin-codegen
   SOURCE riscv_vector.td
   TARGET ClangRISCVVectorBuiltinCG)
+clang_tablegen(riscv_vector_builtin_sema.inc -gen-riscv-vector-builtin-sema
+  SOURCE riscv_vector.td
+  TARGET ClangRISCVVectorBuiltinSema)
diff --git a/clang/include/clang/Basic/TokenKinds.def b/clang/include/clang/Basic/TokenKinds.def
index 7b65a15..84fc089 100644
--- a/clang/include/clang/Basic/TokenKinds.def
+++ b/clang/include/clang/Basic/TokenKinds.def
@@ -908,6 +908,9 @@ PRAGMA_ANNOTATION(pragma_fp)
 // Annotation for the attribute pragma directives - #pragma clang attribute ...
 PRAGMA_ANNOTATION(pragma_attribute)
 
+// Annotation for the riscv pragma directives - #pragma clang riscv intrinsic ...
+PRAGMA_ANNOTATION(pragma_riscv)
+
 // Annotations for module import translated from #include etc.
 ANNOTATION(module_include)
 ANNOTATION(module_begin)
diff --git a/clang/include/clang/Parse/Parser.h b/clang/include/clang/Parse/Parser.h
index a9c85ce..41bfc9f 100644
--- a/clang/include/clang/Parse/Parser.h
+++ b/clang/include/clang/Parse/Parser.h
@@ -215,6 +215,7 @@ class Parser : public CodeCompletionHandler {
   std::unique_ptr<PragmaHandler> AttributePragmaHandler;
   std::unique_ptr<PragmaHandler> MaxTokensHerePragmaHandler;
   std::unique_ptr<PragmaHandler> MaxTokensTotalPragmaHandler;
+  std::unique_ptr<PragmaHandler> RISCVPragmaHandler;
 
   std::unique_ptr<CommentHandler> CommentSemaHandler;
 
diff --git a/clang/include/clang/Sema/RISCVIntrinsicManager.h b/clang/include/clang/Sema/RISCVIntrinsicManager.h
new file mode 100644
index 0000000..5051002
--- /dev/null
+++ b/clang/include/clang/Sema/RISCVIntrinsicManager.h
@@ -0,0 +1,36 @@
+//===- RISCVIntrinsicManager.h - RISC-V Intrinsic Handler -------*- 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
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines the RISCVIntrinsicManager, which handles RISC-V vector
+// intrinsic functions.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_SEMA_RISCVINTRINSICMANAGER_H
+#define LLVM_CLANG_SEMA_RISCVINTRINSICMANAGER_H
+
+namespace clang {
+class Sema;
+class LookupResult;
+class IdentifierInfo;
+class Preprocessor;
+
+namespace sema {
+class RISCVIntrinsicManager {
+public:
+  virtual ~RISCVIntrinsicManager() = default;
+
+  // Create RISC-V intrinsic and insert into symbol table and return true if
+  // found, otherwise return false.
+  virtual bool CreateIntrinsicIfFound(LookupResult &LR, IdentifierInfo *II,
+                                      Preprocessor &PP) = 0;
+};
+} // end namespace sema
+} // end namespace clang
+
+#endif
diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
index b149c24..06ea0b4 100644
--- a/clang/include/clang/Sema/Sema.h
+++ b/clang/include/clang/Sema/Sema.h
@@ -226,6 +226,7 @@ namespace sema {
   class FunctionScopeInfo;
   class LambdaScopeInfo;
   class PossiblyUnreachableDiag;
+  class RISCVIntrinsicManager;
   class SemaPPCallbacks;
   class TemplateDeductionInfo;
 }
@@ -1587,7 +1588,12 @@ public:
   /// assignment.
   llvm::DenseMap<const VarDecl *, int> RefsMinusAssignments;
 
+  /// Indicate RISC-V vector builtin functions enabled or not.
+  bool DeclareRISCVVBuiltins = false;
+
 private:
+  std::unique_ptr<sema::RISCVIntrinsicManager> RVIntrinsicManager;
+
   Optional<std::unique_ptr<DarwinSDKInfo>> CachedDarwinSDKInfo;
 
   bool WarnedDarwinSDKInfoMissing = false;
@@ -13590,6 +13596,8 @@ void Sema::PragmaStack<Sema::AlignPackInfo>::Act(SourceLocation PragmaLocation,
                                                  llvm::StringRef StackSlotLabel,
                                                  AlignPackInfo Value);
 
+std::unique_ptr<sema::RISCVIntrinsicManager>
+CreateRISCVIntrinsicManager(Sema &S);
 } // end namespace clang
 
 namespace llvm {
diff --git a/clang/include/clang/Support/RISCVVIntrinsicUtils.h b/clang/include/clang/Support/RISCVVIntrinsicUtils.h
index a5e7e6d..727f48d 100644
--- a/clang/include/clang/Support/RISCVVIntrinsicUtils.h
+++ b/clang/include/clang/Support/RISCVVIntrinsicUtils.h
@@ -18,6 +18,10 @@
 #include <string>
 #include <vector>
 
+namespace llvm {
+class raw_ostream;
+} // end namespace llvm
+
 namespace clang {
 namespace RISCV {
 
@@ -104,12 +108,14 @@ struct PrototypeDescriptor {
   uint8_t TM = static_cast<uint8_t>(TypeModifier::NoModifier);
 
   bool operator!=(const PrototypeDescriptor &PD) const {
-    return PD.PT != PT || PD.VTM != VTM || PD.TM != TM;
+    return !(*this == PD);
   }
-  bool operator>(const PrototypeDescriptor &PD) const {
-    return !(PD.PT <= PT && PD.VTM <= VTM && PD.TM <= TM);
+  bool operator==(const PrototypeDescriptor &PD) const {
+    return PD.PT == PT && PD.VTM == VTM && PD.TM == TM;
+  }
+  bool operator<(const PrototypeDescriptor &PD) const {
+    return std::tie(PT, VTM, TM) < std::tie(PD.PT, PD.VTM, PD.TM);
   }
-
   static const PrototypeDescriptor Mask;
   static const PrototypeDescriptor Vector;
   static const PrototypeDescriptor VL;
@@ -224,8 +230,12 @@ public:
   bool isFloat(unsigned Width) const {
     return isFloat() && ElementBitwidth == Width;
   }
-
+  bool isConstant() const { return IsConstant; }
   bool isPointer() const { return IsPointer; }
+  unsigned getElementBitwidth() const { return ElementBitwidth; }
+
+  ScalarTypeKind getScalarType() const { return ScalarType; }
+  VScaleVal getScale() const { return Scale; }
 
 private:
   // Verify RVV vector type and set Valid.
@@ -263,18 +273,6 @@ public:
                                                 PrototypeDescriptor Proto);
 };
 
-using RISCVPredefinedMacroT = uint8_t;
-
-enum RISCVPredefinedMacro : RISCVPredefinedMacroT {
-  Basic = 0,
-  V = 1 << 1,
-  Zvfh = 1 << 2,
-  RV64 = 1 << 3,
-  VectorMaxELen64 = 1 << 4,
-  VectorMaxELenFp32 = 1 << 5,
-  VectorMaxELenFp64 = 1 << 6,
-};
-
 enum PolicyScheme : uint8_t {
   SchemeNone,
   HasPassthruOperand,
@@ -302,7 +300,6 @@ private:
   // The types we use to obtain the specific LLVM intrinsic. They are index of
   // InputTypes. -1 means the return type.
   std::vector<int64_t> IntrinsicTypes;
-  RISCVPredefinedMacroT RISCVPredefinedMacros = 0;
   unsigned NF = 1;
 
 public:
@@ -333,9 +330,6 @@ public:
   llvm::StringRef getIRName() const { return IRName; }
   llvm::StringRef getManualCodegen() const { return ManualCodegen; }
   PolicyScheme getPolicyScheme() const { return Scheme; }
-  RISCVPredefinedMacroT getRISCVPredefinedMacros() const {
-    return RISCVPredefinedMacros;
-  }
   unsigned getNF() const { return NF; }
   const std::vector<int64_t> &getIntrinsicTypes() const {
     return IntrinsicTypes;
@@ -349,6 +343,67 @@ public:
                llvm::ArrayRef<PrototypeDescriptor> PrototypeDescriptors);
 };
 
+// RVVRequire should be sync'ed with target features, but only
+// required features used in riscv_vector.td.
+enum RVVRequire : uint8_t {
+  RVV_REQ_None = 0,
+  RVV_REQ_RV64 = 1 << 0,
+  RVV_REQ_FullMultiply = 1 << 1,
+
+  LLVM_MARK_AS_BITMASK_ENUM(RVV_REQ_FullMultiply)
+};
+
+// Raw RVV intrinsic info, used to expand later.
+// This struct is highly compact for minimized code size.
+struct RVVIntrinsicRecord {
+  // Intrinsic name, e.g. vadd_vv
+  const char *Name;
+
+  // Overloaded intrinsic name, could be empty if it can be computed from Name.
+  // e.g. vadd
+  const char *OverloadedName;
+
+  // Prototype for this intrinsic, index of RVVSignatureTable.
+  uint16_t PrototypeIndex;
+
+  // Prototype for masked intrinsic, index of RVVSignatureTable.
+  uint16_t MaskedPrototypeIndex;
+
+  // Suffix of intrinsic name, index of RVVSignatureTable.
+  uint16_t SuffixIndex;
+
+  // Suffix of overloaded intrinsic name, index of RVVSignatureTable.
+  uint16_t OverloadedSuffixIndex;
+
+  // Length of the prototype.
+  uint8_t PrototypeLength;
+
+  // Length of prototype of masked intrinsic.
+  uint8_t MaskedPrototypeLength;
+
+  // Length of intrinsic name suffix.
+  uint8_t SuffixLength;
+
+  // Length of overloaded intrinsic suffix.
+  uint8_t OverloadedSuffixSize;
+
+  // Required target features for this intrinsic.
+  uint8_t RequiredExtensions;
+
+  // Supported type, mask of BasicType.
+  uint8_t TypeRangeMask;
+
+  // Supported LMUL.
+  uint8_t Log2LMULMask;
+
+  // Number of fields, greater than 1 if it's segment load/store.
+  uint8_t NF;
+};
+
+llvm::raw_ostream &operator<<(llvm::raw_ostream &OS,
+                              const RVVIntrinsicRecord &RVVInstrRecord);
+
+LLVM_ENABLE_BITMASK_ENUMS_IN_NAMESPACE();
 } // end namespace RISCV
 
 } // end namespace clang