[clang] 0fff659 - [OpenCL] Reduce size of builtin function tables

[Sven van Haastregt via cfe-commits]

Author: Sven van Haastregt
Date: 2020-02-06T15:08:32Z
New Revision: 0fff6593f8962784d1e2e99994d2ad986f2759a8

URL: https://github.com/llvm/llvm-project/commit/0fff6593f8962784d1e2e99994d2ad986f2759a8
DIFF: https://github.com/llvm/llvm-project/commit/0fff6593f8962784d1e2e99994d2ad986f2759a8.diff

LOG: [OpenCL] Reduce size of builtin function tables

Reduce the size of some of the TableGen'ed OpenCL builtin function
tables:

 - Use bit fields for bools such that they are packed together.  This
   saves about 7kb.

 - Use unsigned short for SignatureTable.  This saves about 10kb.

Added: 
    

Modified: 
    clang/utils/TableGen/ClangOpenCLBuiltinEmitter.cpp

Removed: 
    


################################################################################
diff  --git a/clang/utils/TableGen/ClangOpenCLBuiltinEmitter.cpp b/clang/utils/TableGen/ClangOpenCLBuiltinEmitter.cpp
index 85933e6d3bd3..b930f2daed42 100644
--- a/clang/utils/TableGen/ClangOpenCLBuiltinEmitter.cpp
+++ b/clang/utils/TableGen/ClangOpenCLBuiltinEmitter.cpp
@@ -313,11 +313,11 @@ struct OpenCLTypeStruct {
   // Vector size (if applicable; 0 for scalars and generic types).
   const unsigned VectorWidth;
   // 0 if the type is not a pointer.
-  const bool IsPointer;
+  const bool IsPointer : 1;
   // 0 if the type is not const.
-  const bool IsConst;
+  const bool IsConst : 1;
   // 0 if the type is not volatile.
-  const bool IsVolatile;
+  const bool IsVolatile : 1;
   // Access qualifier.
   const OpenCLAccessQual AccessQualifier;
   // Address space of the pointer (if applicable).
@@ -333,11 +333,11 @@ struct OpenCLBuiltinStruct {
   // index SigTableIndex is the return type.
   const unsigned NumTypes;
   // Function attribute __attribute__((pure))
-  const bool IsPure;
+  const bool IsPure : 1;
   // Function attribute __attribute__((const))
-  const bool IsConst;
+  const bool IsConst : 1;
   // Function attribute __attribute__((convergent))
-  const bool IsConv;
+  const bool IsConv : 1;
   // OpenCL extension(s) required for this overload.
   const unsigned short Extension;
   // First OpenCL version in which this overload was introduced (e.g. CL20).
@@ -473,11 +473,18 @@ void BuiltinNameEmitter::EmitSignatureTable() {
   // Store a type (e.g. int, float, int2, ...). The type is stored as an index
   // of a struct OpenCLType table. Multiple entries following each other form a
   // signature.
-  OS << "static const unsigned SignatureTable[] = {\n";
+  OS << "static const unsigned short SignatureTable[] = {\n";
   for (const auto &P : SignaturesList) {
     OS << "  // " << P.second << "\n  ";
     for (const Record *R : P.first) {
-      OS << TypeMap.find(R)->second << ", ";
+      unsigned Entry = TypeMap.find(R)->second;
+      if (Entry > USHRT_MAX) {
+        // Report an error when seeing an entry that is too large for the
+        // current index type (unsigned short).  When hitting this, the type
+        // of SignatureTable will need to be changed.
+        PrintFatalError("Entry in SignatureTable exceeds limit.");
+      }
+      OS << Entry << ", ";
     }
     OS << "\n";
   }