Use a sidetable in ASTContext for ParmVarDecls whose index exceeds the 8 bits reserved for that value in VarDecl. Fixes PR 10538.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@141273 91177308-0d34-0410-b5e6-96231b3b80d8

include/clang/AST/ASTContext.h

@@ -63,6 +63,7 @@ namespace clang {
   class ObjCIvarDecl;
   class ObjCIvarRefExpr;
   class ObjCPropertyDecl;
+  class ParmVarDecl;
   class RecordDecl;
   class StoredDeclsMap;
   class TagDecl;
@@ -312,6 +313,12 @@ class ASTContext : public llvm::RefCountedBase<ASTContext> {
   typedef UsuallyTinyPtrVector<const CXXMethodDecl> CXXMethodVector;
   llvm::DenseMap<const CXXMethodDecl *, CXXMethodVector> OverriddenMethods;
 
+  /// \brief Mapping that stores parameterIndex values for ParmVarDecls
+  /// when that value exceeds the bitfield size of
+  /// ParmVarDeclBits.ParameterIndex.
+  typedef llvm::DenseMap<const VarDecl *, unsigned> ParameterIndexTable;
+  ParameterIndexTable ParamIndices;  
+  
   TranslationUnitDecl *TUDecl;
 
   /// SourceMgr - The associated SourceManager object.
@@ -1622,6 +1629,15 @@ public:
   /// it is not used.
   bool DeclMustBeEmitted(const Decl *D);
 
+  
+  /// \brief Used by ParmVarDecl to store on the side the
+  /// index of the parameter when it exceeds the size of the normal bitfield.
+  void setParameterIndex(const ParmVarDecl *D, unsigned index);
+
+  /// \brief Used by ParmVarDecl to retrieve on the side the
+  /// index of the parameter when it exceeds the size of the normal bitfield.
+  unsigned getParameterIndex(const ParmVarDecl *D) const;
+  
   //===--------------------------------------------------------------------===//
   //                    Statistics
   //===--------------------------------------------------------------------===//

include/clang/AST/Decl.h

@@ -1246,7 +1246,7 @@ public:
 
   /// Returns the index of this parameter in its prototype or method scope.
   unsigned getFunctionScopeIndex() const {
-    return ParmVarDeclBits.ParameterIndex;
+    return getParameterIndex();
   }
 
   ObjCDeclQualifier getObjCDeclQualifier() const {
@@ -1365,11 +1365,24 @@ public:
   static bool classofKind(Kind K) { return K == ParmVar; }
   
 private:
+  enum { ParameterIndexSentinel = (1 << NumParameterIndexBits) - 1 };
+
   void setParameterIndex(unsigned parameterIndex) {
+    if (parameterIndex >= ParameterIndexSentinel) {
+      setParameterIndexLarge(parameterIndex);
+      return;
+    }
+    
     ParmVarDeclBits.ParameterIndex = parameterIndex;
     assert(ParmVarDeclBits.ParameterIndex == parameterIndex && "truncation!");
   }
-
+  unsigned getParameterIndex() const {
+    unsigned d = ParmVarDeclBits.ParameterIndex;
+    return d == ParameterIndexSentinel ? getParameterIndexLarge() : d;
+  }
+  
+  void setParameterIndexLarge(unsigned parameterIndex);
+  unsigned getParameterIndexLarge() const;
 };
 
 /// FunctionDecl - An instance of this class is created to represent a

lib/AST/ASTContext.cpp

@@ -6516,3 +6516,14 @@ size_t ASTContext::getSideTableAllocatedMemory() const {
     + llvm::capacity_in_bytes(VariableArrayTypes)
     + llvm::capacity_in_bytes(ClassScopeSpecializationPattern);
 }
+
+void ASTContext::setParameterIndex(const ParmVarDecl *D, unsigned int index) {
+  ParamIndices[D] = index;
+}
+
+unsigned ASTContext::getParameterIndex(const ParmVarDecl *D) const {
+  ParameterIndexTable::const_iterator I = ParamIndices.find(D);
+  assert(I != ParamIndices.end() && 
+         "ParmIndices lacks entry set by ParmVarDecl");
+  return I->second;
+}

lib/AST/Decl.cpp

@@ -1441,6 +1441,15 @@ bool ParmVarDecl::isParameterPack() const {
   return isa<PackExpansionType>(getType());
 }
 
+void ParmVarDecl::setParameterIndexLarge(unsigned parameterIndex) {
+  getASTContext().setParameterIndex(this, parameterIndex);
+  ParmVarDeclBits.ParameterIndex = ParameterIndexSentinel;
+}
+
+unsigned ParmVarDecl::getParameterIndexLarge() const {
+  return getASTContext().getParameterIndex(this);
+}
+
 //===----------------------------------------------------------------------===//
 // FunctionDecl Implementation
 //===----------------------------------------------------------------------===//

test/Sema/many-parameters.c

@@ -0,0 +1,310 @@
+// RUN: %clang_cc1 -fsyntax-only -std=c99 %s
+
+// This test simply tests that the compiler does not crash.  An optimization
+// in ParmVarDecls means that functions with fewer than 256 parameters use a fast path,
+// while those with >= 256 parameters use a slow path.
+//
+// Crash was reported in PR 10538.
+
+void foo(
+int x0,
+int x1,
+int x2,
+int x3,
+int x4,
+int x5,
+int x6,
+int x7,
+int x8,
+int x9,
+int x10,
+int x11,
+int x12,
+int x13,
+int x14,
+int x15,
+int x16,
+int x17,
+int x18,
+int x19,
+int x20,
+int x21,
+int x22,
+int x23,
+int x24,
+int x25,
+int x26,
+int x27,
+int x28,
+int x29,
+int x30,
+int x31,
+int x32,
+int x33,
+int x34,
+int x35,
+int x36,
+int x37,
+int x38,
+int x39,
+int x40,
+int x41,
+int x42,
+int x43,
+int x44,
+int x45,
+int x46,
+int x47,
+int x48,
+int x49,
+int x50,
+int x51,
+int x52,
+int x53,
+int x54,
+int x55,
+int x56,
+int x57,
+int x58,
+int x59,
+int x60,
+int x61,
+int x62,
+int x63,
+int x64,
+int x65,
+int x66,
+int x67,
+int x68,
+int x69,
+int x70,
+int x71,
+int x72,
+int x73,
+int x74,
+int x75,
+int x76,
+int x77,
+int x78,
+int x79,
+int x80,
+int x81,
+int x82,
+int x83,
+int x84,
+int x85,
+int x86,
+int x87,
+int x88,
+int x89,
+int x90,
+int x91,
+int x92,
+int x93,
+int x94,
+int x95,
+int x96,
+int x97,
+int x98,
+int x99,
+int x100,
+int x101,
+int x102,
+int x103,
+int x104,
+int x105,
+int x106,
+int x107,
+int x108,
+int x109,
+int x110,
+int x111,
+int x112,
+int x113,
+int x114,
+int x115,
+int x116,
+int x117,
+int x118,
+int x119,
+int x120,
+int x121,
+int x122,
+int x123,
+int x124,
+int x125,
+int x126,
+int x127,
+int x128,
+int x129,
+int x130,
+int x131,
+int x132,
+int x133,
+int x134,
+int x135,
+int x136,
+int x137,
+int x138,
+int x139,
+int x140,
+int x141,
+int x142,
+int x143,
+int x144,
+int x145,
+int x146,
+int x147,
+int x148,
+int x149,
+int x150,
+int x151,
+int x152,
+int x153,
+int x154,
+int x155,
+int x156,
+int x157,
+int x158,
+int x159,
+int x160,
+int x161,
+int x162,
+int x163,
+int x164,
+int x165,
+int x166,
+int x167,
+int x168,
+int x169,
+int x170,
+int x171,
+int x172,
+int x173,
+int x174,
+int x175,
+int x176,
+int x177,
+int x178,
+int x179,
+int x180,
+int x181,
+int x182,
+int x183,
+int x184,
+int x185,
+int x186,
+int x187,
+int x188,
+int x189,
+int x190,
+int x191,
+int x192,
+int x193,
+int x194,
+int x195,
+int x196,
+int x197,
+int x198,
+int x199,
+int x200,
+int x201,
+int x202,
+int x203,
+int x204,
+int x205,
+int x206,
+int x207,
+int x208,
+int x209,
+int x210,
+int x211,
+int x212,
+int x213,
+int x214,
+int x215,
+int x216,
+int x217,
+int x218,
+int x219,
+int x220,
+int x221,
+int x222,
+int x223,
+int x224,
+int x225,
+int x226,
+int x227,
+int x228,
+int x229,
+int x230,
+int x231,
+int x232,
+int x233,
+int x234,
+int x235,
+int x236,
+int x237,
+int x238,
+int x239,
+int x240,
+int x241,
+int x242,
+int x243,
+int x244,
+int x245,
+int x246,
+int x247,
+int x248,
+int x249,
+int x250,
+int x251,
+int x252,
+int x253,
+int x254,
+int x255,
+int x256,
+int x257,
+int x258,
+int x259,
+int x260,
+int x261,
+int x262,
+int x263,
+int x264,
+int x265,
+int x266,
+int x267,
+int x268,
+int x269,
+int x270,
+int x271,
+int x272,
+int x273,
+int x274,
+int x275,
+int x276,
+int x277,
+int x278,
+int x279,
+int x280,
+int x281,
+int x282,
+int x283,
+int x284,
+int x285,
+int x286,
+int x287,
+int x288,
+int x289,
+int x290,
+int x291,
+int x292,
+int x293,
+int x294,
+int x295,
+int x296,
+int x297,
+int x298,
+int x299
+);