[clang][Serialization][RISCV] Increase the number of reserved predefined type IDs

In D152070 we added many new intrinsic types required for the RISC-V
Vector Extension.

This was crashing when loading the AST as those types are intrinsically
added to the AST (they don't come from the disk).

The total number required now by clang exceeds 400 so increasing the
value to 500 solves the problem. This value was already increased in
D92715 but I assume this has some impact on the on-disk format.

Also add a static assert to avoid this happening again in the future.

Differential Revision: https://reviews.llvm.org/D153111

Author: rofirrim

clang/include/clang/Serialization/ASTBitCodes.h

@@ -1099,14 +1099,22 @@ enum PredefinedTypeIDs {
 // \brief WebAssembly reference types with auto numeration
 #define WASM_TYPE(Name, Id, SingletonId) PREDEF_TYPE_##Id##_ID,
 #include "clang/Basic/WebAssemblyReferenceTypes.def"
+  // Sentinel value. Considered a predefined type but not useable as one.
+  PREDEF_TYPE_LAST_ID
 };
 
 /// The number of predefined type IDs that are reserved for
 /// the PREDEF_TYPE_* constants.
 ///
 /// Type IDs for non-predefined types will start at
 /// NUM_PREDEF_TYPE_IDs.
-const unsigned NUM_PREDEF_TYPE_IDS = 300;
+const unsigned NUM_PREDEF_TYPE_IDS = 500;
+
+// Ensure we do not overrun the predefined types we reserved
+// in the enum PredefinedTypeIDs above.
+static_assert(PREDEF_TYPE_LAST_ID < NUM_PREDEF_TYPE_IDS,
+              "Too many enumerators in PredefinedTypeIDs. Review the value of "
+              "NUM_PREDEF_TYPE_IDS");
 
 /// Record codes for each kind of type.
 ///

clang/lib/Serialization/ASTReader.cpp

@@ -6983,6 +6983,10 @@ QualType ASTReader::GetType(TypeID ID) {
   if (Index < NUM_PREDEF_TYPE_IDS) {
     QualType T;
     switch ((PredefinedTypeIDs)Index) {
+    case PREDEF_TYPE_LAST_ID:
+      // We should never use this one.
+      llvm_unreachable("Invalid predefined type");
+      break;
     case PREDEF_TYPE_NULL_ID:
       return QualType();
     case PREDEF_TYPE_VOID_ID:

clang/test/Modules/embed-files-compressed.cpp

@@ -17,7 +17,7 @@
 // RUN: %clang_cc1 -fmodules -I%t -fmodules-cache-path=%t -fmodule-name=a -emit-module %t/modulemap -fmodules-embed-all-files -o %t/a.pcm
 //
 // The above embeds ~4.5MB of highly-predictable /s and \ns into the pcm file.
-// Check that the resulting file is under 40KB:
+// Check that the resulting file is under 60KB:
 //
 // RUN: wc -c %t/a.pcm | FileCheck --check-prefix=CHECK-SIZE %s
-// CHECK-SIZE: {{(^|[^0-9])[123][0-9][0-9][0-9][0-9]($|[^0-9])}}
+// CHECK-SIZE: {{(^|[^0-9])[1-5][0-9][0-9][0-9][0-9]($|[^0-9])}}

clang/test/Modules/empty.modulemap

@@ -13,8 +13,8 @@
 // The module file should be identical each time we produce it.
 // RUN: diff %t/base.pcm %t/check.pcm
 //
-// We expect an empty module to be less than 40KB (and at least 10K, for now).
+// We expect an empty module to be less than 60KB (and at least 10K, for now).
 // RUN: wc -c %t/base.pcm | FileCheck --check-prefix=CHECK-SIZE %s
-// CHECK-SIZE: {{(^|[^0-9])[123][0-9][0-9][0-9][0-9]($|[^0-9])}}
+// CHECK-SIZE: {{(^|[^0-9])[1-5][0-9][0-9][0-9][0-9]($|[^0-9])}}
 
 module empty { header "Inputs/empty.h" export * }