Revert "[ubsan] Display correct runtime messages for negative _BitInt (#93612)"

This reverts commit 49001d5.

Author: earnol

clang/lib/CodeGen/CGExpr.cpp

@@ -41,7 +41,6 @@
 #include "llvm/IR/MatrixBuilder.h"
 #include "llvm/Passes/OptimizationLevel.h"
 #include "llvm/Support/ConvertUTF.h"
-#include "llvm/Support/Endian.h"
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/SaveAndRestore.h"
@@ -65,22 +64,6 @@ static llvm::cl::opt<bool> ClSanitizeGuardChecks(
     "ubsan-guard-checks", llvm::cl::Optional,
     llvm::cl::desc("Guard UBSAN checks with `llvm.allow.ubsan.check()`."));
 
-//===--------------------------------------------------------------------===//
-//                        Defines for metadata
-//===--------------------------------------------------------------------===//
-
-// Those values are crucial to be the SAME as in ubsan runtime library.
-enum VariableTypeDescriptorKind : uint16_t {
-  /// An integer type.
-  TK_Integer = 0x0000,
-  /// A floating-point type.
-  TK_Float = 0x0001,
-  /// An _BitInt(N) type.
-  TK_BitInt = 0x0002,
-  /// Any other type. The value representation is unspecified.
-  TK_Unknown = 0xffff
-};
-
 //===--------------------------------------------------------------------===//
 //                        Miscellaneous Helper Methods
 //===--------------------------------------------------------------------===//
@@ -3315,40 +3298,22 @@ LValue CodeGenFunction::EmitPredefinedLValue(const PredefinedExpr *E) {
 ///   { i16 TypeKind, i16 TypeInfo }
 /// \endcode
 ///
-/// followed by an array of i8 containing the type name with extra information
-/// for BitInt. TypeKind is TK_Integer(0) for an integer, TK_Float(1) for a
-/// floating point value, TK_BitInt(2) for BitInt and TK_Unknown(0xFFFF) for
-/// anything else.
+/// followed by an array of i8 containing the type name. TypeKind is 0 for an
+/// integer, 1 for a floating point value, and -1 for anything else.
 llvm::Constant *CodeGenFunction::EmitCheckTypeDescriptor(QualType T) {
   // Only emit each type's descriptor once.
   if (llvm::Constant *C = CGM.getTypeDescriptorFromMap(T))
     return C;
 
-  uint16_t TypeKind = TK_Unknown;
+  uint16_t TypeKind = -1;
   uint16_t TypeInfo = 0;
-  bool IsBitInt = false;
 
   if (T->isIntegerType()) {
-    TypeKind = TK_Integer;
+    TypeKind = 0;
     TypeInfo = (llvm::Log2_32(getContext().getTypeSize(T)) << 1) |
                (T->isSignedIntegerType() ? 1 : 0);
-    // Follow suggestion from https://github.com/llvm/llvm-project/issues/64100
-    // So we can write the exact amount of bits in TypeName after '\0'
-    // making it <diagnostic-like type name>.'\0'.<32-bit width>.
-    if (T->isSignedIntegerType() && T->getAs<BitIntType>()) {
-      // Do a sanity checks as we are using 32-bit type to store bit length.
-      assert((getContext().getTypeSize(T) > 0) &&
-             " non positive amount of bits in __BitInt type");
-      assert((getContext().getTypeSize(T) <= 0xFFFFFFFF) &&
-             " too many bits in __BitInt type");
-
-      // Redefine TypeKind with the actual __BitInt type if we have signed
-      // BitInt.
-      TypeKind = TK_BitInt;
-      IsBitInt = true;
-    }
   } else if (T->isFloatingType()) {
-    TypeKind = TK_Float;
+    TypeKind = 1;
     TypeInfo = getContext().getTypeSize(T);
   }
 
@@ -3359,20 +3324,6 @@ llvm::Constant *CodeGenFunction::EmitCheckTypeDescriptor(QualType T) {
       DiagnosticsEngine::ak_qualtype, (intptr_t)T.getAsOpaquePtr(), StringRef(),
       StringRef(), std::nullopt, Buffer, std::nullopt);
 
-  if (IsBitInt) {
-    // The Structure is: 0 to end the string, 32 bit unsigned integer in target
-    // endianness, zero.
-    char S[6] = {'\0', '\0', '\0', '\0', '\0', '\0'};
-    const auto *EIT = T->castAs<BitIntType>();
-    uint32_t Bits = EIT->getNumBits();
-    llvm::support::endian::write32(S + 1, Bits,
-                                   getTarget().isBigEndian()
-                                       ? llvm::endianness::big
-                                       : llvm::endianness::little);
-    StringRef str = StringRef(S, sizeof(S) / sizeof(decltype(S[0])));
-    Buffer.append(str);
-  }
-
   llvm::Constant *Components[] = {
     Builder.getInt16(TypeKind), Builder.getInt16(TypeInfo),
     llvm::ConstantDataArray::getString(getLLVMContext(), Buffer)

compiler-rt/lib/ubsan/ubsan_value.cpp

@@ -67,21 +67,18 @@ const char *__ubsan::getObjCClassName(ValueHandle Pointer) {
 
 SIntMax Value::getSIntValue() const {
   CHECK(getType().isSignedIntegerTy());
-  // Val was zero-extended to ValueHandle. Sign-extend from original width
-  // to SIntMax.
-  const unsigned ExtraBits =
-      sizeof(SIntMax) * 8 - getType().getIntegerBitCount();
   if (isInlineInt()) {
+    // Val was zero-extended to ValueHandle. Sign-extend from original width
+    // to SIntMax.
+    const unsigned ExtraBits =
+      sizeof(SIntMax) * 8 - getType().getIntegerBitWidth();
     return SIntMax(UIntMax(Val) << ExtraBits) >> ExtraBits;
   }
-  if (getType().getIntegerBitWidth() == 64) {
-    return SIntMax(UIntMax(*reinterpret_cast<s64 *>(Val)) << ExtraBits) >>
-           ExtraBits;
-  }
+  if (getType().getIntegerBitWidth() == 64)
+    return *reinterpret_cast<s64*>(Val);
 #if HAVE_INT128_T
   if (getType().getIntegerBitWidth() == 128)
-    return SIntMax(UIntMax(*reinterpret_cast<s128 *>(Val)) << ExtraBits) >>
-           ExtraBits;
+    return *reinterpret_cast<s128*>(Val);
 #else
   if (getType().getIntegerBitWidth() == 128)
     UNREACHABLE("libclang_rt.ubsan was built without __int128 support");

compiler-rt/lib/ubsan/ubsan_value.h

@@ -103,13 +103,6 @@ class TypeDescriptor {
     /// representation is that of bitcasting the floating-point value to an
     /// integer type.
     TK_Float = 0x0001,
-    /// An _BitInt(N) type. Lowest bit is 1 for a signed value, 0 for an
-    /// unsigned value. Remaining bits are log_2(bit_width). The value
-    /// representation is the integer itself if it fits into a ValueHandle, and
-    /// a pointer to the integer otherwise. TypeName contains the true width
-    /// of the type for the signed _BitInt(N) type stored after zero bit after
-    /// TypeName as 32-bit unsigned integer.
-    TK_BitInt = 0x0002,
     /// Any other type. The value representation is unspecified.
     TK_Unknown = 0xffff
   };
@@ -120,15 +113,10 @@ class TypeDescriptor {
     return static_cast<Kind>(TypeKind);
   }
 
-  bool isIntegerTy() const {
-    return getKind() == TK_Integer || getKind() == TK_BitInt;
-  }
-  bool isBitIntTy() const { return getKind() == TK_BitInt; }
-
+  bool isIntegerTy() const { return getKind() == TK_Integer; }
   bool isSignedIntegerTy() const {
     return isIntegerTy() && (TypeInfo & 1);
   }
-  bool isSignedBitIntTy() const { return isBitIntTy() && (TypeInfo & 1); }
   bool isUnsignedIntegerTy() const {
     return isIntegerTy() && !(TypeInfo & 1);
   }
@@ -137,26 +125,6 @@ class TypeDescriptor {
     return 1 << (TypeInfo >> 1);
   }
 
-  const char *getBitIntBitCountPointer() const {
-    CHECK(isBitIntTy());
-    CHECK(isSignedBitIntTy());
-    // Scan Name for zero and return the next address
-    const char *p = getTypeName();
-    while (*p != '\0') {
-      ++p;
-    }
-    // Return the next address
-    return p + 1;
-  }
-
-  unsigned getIntegerBitCount() const {
-    CHECK(isIntegerTy());
-    if (isSignedBitIntTy())
-      return *reinterpret_cast<const u32 *>(getBitIntBitCountPointer());
-    else
-      return getIntegerBitWidth();
-  }
-
   bool isFloatTy() const { return getKind() == TK_Float; }
   unsigned getFloatBitWidth() const {
     CHECK(isFloatTy());