[CodeView] Saturate values bigger than supported by APInt.

This fixes an assert firing when compiling code which involves 128 bit
integrals.

This would trigger runtime checks similar to this:
```
Assertion failed: getMinSignedBits() <= 64 && "Too many bits for int64_t", file llvm/include/llvm/ADT/APInt.h, line 1646
```

To get around this, we just saturate those big values.

Reviewed By: rnk

Differential Revision: https://reviews.llvm.org/D105320

include/llvm/ADT/APInt.h

@@ -109,11 +109,6 @@ private:
     U.pVal = val;
   }
 
-  /// Determine if this APInt just has one word to store value.
-  ///
-  /// \returns true if the number of bits <= 64, false otherwise.
-  bool isSingleWord() const { return BitWidth <= APINT_BITS_PER_WORD; }
-
   /// Determine which word a bit is in.
   ///
   /// \returns the word position for the specified bit position.
@@ -356,6 +351,11 @@ public:
   /// \name Value Tests
   /// @{
 
+  /// Determine if this APInt just has one word to store value.
+  ///
+  /// \returns true if the number of bits <= 64, false otherwise.
+  bool isSingleWord() const { return BitWidth <= APINT_BITS_PER_WORD; }
+
   /// Determine sign of this APInt.
   ///
   /// This tests the high bit of this APInt to determine if it is set.

include/llvm/IR/DIBuilder.h

@@ -182,7 +182,7 @@ namespace llvm {
 
     /// Create a single enumerator value.
     DIEnumerator *createEnumerator(StringRef Name, APSInt Value);
-    DIEnumerator *createEnumerator(StringRef Name, int64_t Val,
+    DIEnumerator *createEnumerator(StringRef Name, uint64_t Val,
                                    bool IsUnsigned = false);
 
     /// Create a DWARF unspecified type.

lib/CodeGen/AsmPrinter/CodeViewDebug.cpp

@@ -2116,6 +2116,7 @@ TypeIndex CodeViewDebug::lowerTypeEnum(const DICompositeType *Ty) {
       // We assume that the frontend provides all members in source declaration
       // order, which is what MSVC does.
       if (auto *Enumerator = dyn_cast_or_null<DIEnumerator>(Element)) {
+        // FIXME: Is it correct to always emit these as unsigned here?
         EnumeratorRecord ER(MemberAccess::Public,
                             APSInt(Enumerator->getValue(), true),
                             Enumerator->getName());
@@ -3157,6 +3158,27 @@ void CodeViewDebug::emitGlobalVariableList(ArrayRef<CVGlobalVariable> Globals) {
   }
 }
 
+void CodeViewDebug::emitConstantSymbolRecord(const DIType *DTy, APSInt &Value,
+                                             const std::string &QualifiedName) {
+  MCSymbol *SConstantEnd = beginSymbolRecord(SymbolKind::S_CONSTANT);
+  OS.AddComment("Type");
+  OS.emitInt32(getTypeIndex(DTy).getIndex());
+
+  OS.AddComment("Value");
+
+  // Encoded integers shouldn't need more than 10 bytes.
+  uint8_t Data[10];
+  BinaryStreamWriter Writer(Data, llvm::support::endianness::little);
+  CodeViewRecordIO IO(Writer);
+  cantFail(IO.mapEncodedInteger(Value));
+  StringRef SRef((char *)Data, Writer.getOffset());
+  OS.emitBinaryData(SRef);
+
+  OS.AddComment("Name");
+  emitNullTerminatedSymbolName(OS, QualifiedName);
+  endSymbolRecord(SConstantEnd);
+}
+
 void CodeViewDebug::emitStaticConstMemberList() {
   for (const DIDerivedType *DTy : StaticConstMembers) {
     const DIScope *Scope = DTy->getScope();
@@ -3172,24 +3194,8 @@ void CodeViewDebug::emitStaticConstMemberList() {
     else
       llvm_unreachable("cannot emit a constant without a value");
 
-    std::string QualifiedName = getFullyQualifiedName(Scope, DTy->getName());
+    emitConstantSymbolRecord(DTy->getBaseType(), Value,
-
+                             getFullyQualifiedName(Scope, DTy->getName()));
-    MCSymbol *SConstantEnd = beginSymbolRecord(SymbolKind::S_CONSTANT);
-    OS.AddComment("Type");
-    OS.emitInt32(getTypeIndex(DTy->getBaseType()).getIndex());
-    OS.AddComment("Value");
-
-    // Encoded integers shouldn't need more than 10 bytes.
-    uint8_t Data[10];
-    BinaryStreamWriter Writer(Data, llvm::support::endianness::little);
-    CodeViewRecordIO IO(Writer);
-    cantFail(IO.mapEncodedInteger(Value));
-    StringRef SRef((char *)Data, Writer.getOffset());
-    OS.emitBinaryData(SRef);
-
-    OS.AddComment("Name");
-    emitNullTerminatedSymbolName(OS, QualifiedName);
-    endSymbolRecord(SConstantEnd);
   }
 }
 
@@ -3253,22 +3259,6 @@ void CodeViewDebug::emitDebugInfoForGlobal(const CVGlobalVariable &CVGV) {
                           ? true
                           : DebugHandlerBase::isUnsignedDIType(DIGV->getType());
     APSInt Value(APInt(/*BitWidth=*/64, DIE->getElement(1)), isUnsigned);
-
+    emitConstantSymbolRecord(DIGV->getType(), Value, QualifiedName);
-    MCSymbol *SConstantEnd = beginSymbolRecord(SymbolKind::S_CONSTANT);
-    OS.AddComment("Type");
-    OS.emitInt32(getTypeIndex(DIGV->getType()).getIndex());
-    OS.AddComment("Value");
-
-    // Encoded integers shouldn't need more than 10 bytes.
-    uint8_t data[10];
-    BinaryStreamWriter Writer(data, llvm::support::endianness::little);
-    CodeViewRecordIO IO(Writer);
-    cantFail(IO.mapEncodedInteger(Value));
-    StringRef SRef((char *)data, Writer.getOffset());
-    OS.emitBinaryData(SRef);
-
-    OS.AddComment("Name");
-    emitNullTerminatedSymbolName(OS, QualifiedName);
-    endSymbolRecord(SConstantEnd);
   }
 }

lib/CodeGen/AsmPrinter/CodeViewDebug.h

@@ -315,6 +315,8 @@ class LLVM_LIBRARY_VISIBILITY CodeViewDebug : public DebugHandlerBase {
   void collectDebugInfoForGlobals();
   void emitDebugInfoForGlobals();
   void emitGlobalVariableList(ArrayRef<CVGlobalVariable> Globals);
+  void emitConstantSymbolRecord(const DIType *DTy, APSInt &Value,
+                                const std::string &QualifiedName);
   void emitDebugInfoForGlobal(const CVGlobalVariable &CVGV);
   void emitStaticConstMemberList();
 

lib/DebugInfo/CodeView/CodeViewRecordIO.cpp

@@ -188,14 +188,17 @@ Error CodeViewRecordIO::mapEncodedInteger(uint64_t &Value,
 
 Error CodeViewRecordIO::mapEncodedInteger(APSInt &Value, const Twine &Comment) {
   if (isStreaming()) {
+    // FIXME: We also need to handle big values here, but it's
+    //        not clear how we can excercise this code path yet.
     if (Value.isSigned())
       emitEncodedSignedInteger(Value.getSExtValue(), Comment);
     else
       emitEncodedUnsignedInteger(Value.getZExtValue(), Comment);
   } else if (isWriting()) {
     if (Value.isSigned())
-      return writeEncodedSignedInteger(Value.getSExtValue());
+      return writeEncodedSignedInteger(
-    return writeEncodedUnsignedInteger(Value.getZExtValue());
+          Value.isSingleWord() ? Value.getSExtValue() : INT64_MIN);
+    return writeEncodedUnsignedInteger(Value.getLimitedValue());
   } else
     return consume(*Reader, Value);
   return Error::success();
@@ -273,6 +276,9 @@ Error CodeViewRecordIO::mapStringZVectorZ(std::vector<StringRef> &Value,
 
 void CodeViewRecordIO::emitEncodedSignedInteger(const int64_t &Value,
                                                 const Twine &Comment) {
+  // FIXME: There are no test cases covering this function.
+  // This may be because we always consider enumerators to be unsigned.
+  // See FIXME at CodeViewDebug.cpp : CodeViewDebug::lowerTypeEnum.
   if (Value >= std::numeric_limits<int8_t>::min()) {
     Streamer->emitIntValue(LF_CHAR, 2);
     emitComment(Comment);
@@ -291,8 +297,8 @@ void CodeViewRecordIO::emitEncodedSignedInteger(const int64_t &Value,
   } else {
     Streamer->emitIntValue(LF_QUADWORD, 2);
     emitComment(Comment);
-    Streamer->emitIntValue(Value, 4);
+    Streamer->emitIntValue(Value, 4); // FIXME: Why not 8 (size of quadword)?
-    incrStreamedLen(6);
+    incrStreamedLen(6);               // FIXME: Why not 10 (8 + 2)?
   }
 }
 
@@ -313,10 +319,11 @@ void CodeViewRecordIO::emitEncodedUnsignedInteger(const uint64_t &Value,
     Streamer->emitIntValue(Value, 4);
     incrStreamedLen(6);
   } else {
+    // FIXME: There are no test cases covering this block.
     Streamer->emitIntValue(LF_UQUADWORD, 2);
     emitComment(Comment);
     Streamer->emitIntValue(Value, 8);
-    incrStreamedLen(6);
+    incrStreamedLen(6); // FIXME: Why not 10 (8 + 2)?
   }
 }
 

lib/IR/DIBuilder.cpp

@@ -243,7 +243,7 @@ DIMacroFile *DIBuilder::createTempMacroFile(DIMacroFile *Parent,
   return MF;
 }
 
-DIEnumerator *DIBuilder::createEnumerator(StringRef Name, int64_t Val,
+DIEnumerator *DIBuilder::createEnumerator(StringRef Name, uint64_t Val,
                                           bool IsUnsigned) {
   assert(!Name.empty() && "Unable to create enumerator without name");
   return DIEnumerator::get(VMContext, APInt(64, Val, !IsUnsigned), IsUnsigned,

test/DebugInfo/COFF/integer-128.ll

@@ -0,0 +1,136 @@
+; RUN: llc < %s | FileCheck %s --check-prefix=ASM
+
+; // C++ source to regenerate:
+; enum class uns : __uint128_t { unsval = __uint128_t(1) << 64 };
+; uns t1() { return uns::unsval; }
+; enum class sig : __int128 { sigval = -(__int128(1) << 64) };
+; sig t2() { return sig::sigval; }
+; struct test {
+;   static const __uint128_t u128 = __uint128_t(1) << 64;
+;   static const __int128    s128 = -(__int128(1) << 64);
+; };
+; test t3() { return test(); }
+; 
+; $ clang a.cpp -S -emit-llvm -g -gcodeview
+
+; ------------------------------------------------------------------------------
+
+; ASM-LABEL: .long   241                             # Symbol subsection for globals
+;
+; ASM-LABEL: .short	4359                            # Record kind: S_CONSTANT
+; ASM-NEXT:  .long	4110                            # Type
+; ASM-NEXT:  .byte	0x0a, 0x80, 0xff, 0xff          # Value
+; ASM-NEXT:  .byte	0xff, 0xff, 0xff, 0xff
+; ASM-NEXT:  .byte	0xff, 0xff
+; ASM-NEXT:  .asciz	"test::u128"                    # Name
+; ASM-NEXT:  .p2align	2
+;
+; ASM-LABEL: .short	4359                            # Record kind: S_CONSTANT
+; ASM-NEXT:  .long	4111                            # Type
+; ASM-NEXT:  .byte	0x09, 0x80, 0x00, 0x00          # Value
+; ASM-NEXT:  .byte	0x00, 0x00, 0x00, 0x00
+; ASM-NEXT:  .byte	0x00, 0x80
+; ASM-NEXT:  .asciz	"test::s128"                    # Name
+; ASM-NEXT:  .p2align	2
+;
+; ASM-LABEL: .short	0x1203                          # Record kind: LF_FIELDLIST
+; ASM-NEXT:  .short	0x1502                          # Member kind: Enumerator ( LF_ENUMERATE )
+; ASM-NEXT:  .short	0x3                             # Attrs: Public
+; ASM-NEXT:  .short	0x800a
+; ASM-NEXT:  .quad	0xffffffffffffffff              # EnumValue
+; ASM-NEXT:  .asciz	"unsval"                        # Name
+;
+; ASM-LABEL: .short	0x1203                          # Record kind: LF_FIELDLIST
+; ASM-NEXT:  .short	0x1502                          # Member kind: Enumerator ( LF_ENUMERATE )
+; ASM-NEXT:  .short	0x3                             # Attrs: Public
+; ASM-NEXT:  .short	0x800a
+; ASM-NEXT:  .quad	0xffffffffffffffff              # EnumValue
+; ASM-NEXT:  .asciz	"sigval"                        # Name
+
+; ------------------------------------------------------------------------------
+
+; ModuleID = 'a.cpp'
+source_filename = "a.cpp"
+target datalayout = "e-m:w-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-windows-gnu"
+
+%struct.test = type { i8 }
+
+; Function Attrs: mustprogress noinline nounwind optnone
+define dso_local <2 x i64> @_Z2t1v() #0 !dbg !23 {
+entry:
+  %retval = alloca i128, align 16
+  store i128 18446744073709551616, i128* %retval, align 16, !dbg !27
+  %0 = bitcast i128* %retval to <2 x i64>*, !dbg !27
+  %1 = load <2 x i64>, <2 x i64>* %0, align 16, !dbg !27
+  ret <2 x i64> %1, !dbg !27
+}
+
+; Function Attrs: mustprogress noinline nounwind optnone
+define dso_local <2 x i64> @_Z2t2v() #0 !dbg !28 {
+entry:
+  %retval = alloca i128, align 16
+  store i128 -18446744073709551616, i128* %retval, align 16, !dbg !31
+  %0 = bitcast i128* %retval to <2 x i64>*, !dbg !31
+  %1 = load <2 x i64>, <2 x i64>* %0, align 16, !dbg !31
+  ret <2 x i64> %1, !dbg !31
+}
+
+; Function Attrs: mustprogress noinline nounwind optnone
+define dso_local i8 @_Z2t3v() #1 !dbg !32 {
+entry:
+  %retval = alloca %struct.test, align 1
+  %coerce.dive = getelementptr inbounds %struct.test, %struct.test* %retval, i32 0, i32 0, !dbg !41
+  %0 = load i8, i8* %coerce.dive, align 1, !dbg !41
+  ret i8 %0, !dbg !41
+}
+
+attributes #0 = { mustprogress noinline nounwind optnone "frame-pointer"="none" "min-legal-vector-width"="128" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-features"="+cx8,+mmx,+sse,+sse2,+x87" }
+attributes #1 = { mustprogress noinline nounwind optnone "frame-pointer"="none" "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-features"="+cx8,+mmx,+sse,+sse2,+x87" }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!19, !20, !21}
+!llvm.ident = !{!22}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !1, producer: "clang version 13.0.0", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, globals: !14, splitDebugInlining: false, nameTableKind: None)
+!1 = !DIFile(filename: "a.cpp", directory: ".", checksumkind: CSK_MD5, checksum: "b37f4034fd610917975e9c5ff097fa6b")
+!2 = !{!3, !10}
+!3 = !DICompositeType(tag: DW_TAG_enumeration_type, name: "uns", file: !4, line: 4, baseType: !5, size: 128, flags: DIFlagEnumClass, elements: !8, identifier: "_ZTS3uns")
+!4 = !DIFile(filename: "a.cpp", directory: ".", checksumkind: CSK_MD5, checksum: "b37f4034fd610917975e9c5ff097fa6b")
+!5 = !DIDerivedType(tag: DW_TAG_typedef, name: "__uint128_t", file: !6, baseType: !7)
+!6 = !DIFile(filename: "a.cpp", directory: ".")
+!7 = !DIBasicType(name: "unsigned __int128", size: 128, encoding: DW_ATE_unsigned)
+!8 = !{!9}
+!9 = !DIEnumerator(name: "unsval", value: 18446744073709551616, isUnsigned: true)
+!10 = !DICompositeType(tag: DW_TAG_enumeration_type, name: "sig", file: !4, line: 7, baseType: !11, size: 128, flags: DIFlagEnumClass, elements: !12, identifier: "_ZTS3sig")
+!11 = !DIBasicType(name: "__int128", size: 128, encoding: DW_ATE_signed)
+!12 = !{!13}
+!13 = !DIEnumerator(name: "sigval", value: -18446744073709551616)
+!14 = !{!15, !17}
+!15 = !DIGlobalVariableExpression(var: !16, expr: !DIExpression())
+!16 = distinct !DIGlobalVariable(name: "unsval", scope: !0, file: !4, line: 4, type: !3, isLocal: true, isDefinition: true)
+!17 = !DIGlobalVariableExpression(var: !18, expr: !DIExpression())
+!18 = distinct !DIGlobalVariable(name: "sigval", scope: !0, file: !4, line: 7, type: !10, isLocal: true, isDefinition: true)
+!19 = !{i32 2, !"CodeView", i32 1}
+!20 = !{i32 2, !"Debug Info Version", i32 3}
+!21 = !{i32 1, !"wchar_size", i32 2}
+!22 = !{!"clang version 13.0.0"}
+!23 = distinct !DISubprogram(name: "t1", linkageName: "_Z2t1v", scope: !4, file: !4, line: 5, type: !24, scopeLine: 5, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !26)
+!24 = !DISubroutineType(types: !25)
+!25 = !{!3}
+!26 = !{}
+!27 = !DILocation(line: 5, column: 12, scope: !23)
+!28 = distinct !DISubprogram(name: "t2", linkageName: "_Z2t2v", scope: !4, file: !4, line: 8, type: !29, scopeLine: 8, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !26)
+!29 = !DISubroutineType(types: !30)
+!30 = !{!10}
+!31 = !DILocation(line: 8, column: 12, scope: !28)
+!32 = distinct !DISubprogram(name: "t3", linkageName: "_Z2t3v", scope: !4, file: !4, line: 14, type: !33, scopeLine: 14, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !26)
+!33 = !DISubroutineType(types: !34)
+!34 = !{!35}
+!35 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "test", file: !4, line: 10, size: 8, flags: DIFlagTypePassByValue, elements: !36, identifier: "_ZTS4test")
+!36 = !{!37, !39}
+!37 = !DIDerivedType(tag: DW_TAG_member, name: "u128", scope: !35, file: !4, line: 11, baseType: !38, flags: DIFlagStaticMember, extraData: i128 18446744073709551616)
+!38 = !DIDerivedType(tag: DW_TAG_const_type, baseType: !5)
+!39 = !DIDerivedType(tag: DW_TAG_member, name: "s128", scope: !35, file: !4, line: 12, baseType: !40, flags: DIFlagStaticMember, extraData: i128 -18446744073709551616)
+!40 = !DIDerivedType(tag: DW_TAG_const_type, baseType: !11)
+!41 = !DILocation(line: 14, column: 13, scope: !32)