[demangler] Support C23 _BitInt type

[aaron.ballman]

Thank you for this! It looks correct to me, but the changes should probably come with some test coverage as well.

[zsrkmyn]

In D122530#3410074, @aaron.ballman wrote:

Thank you for this! It looks correct to me, but the changes should probably come with some test coverage as well.

There are actually some tests in libcxxabi/test/test_demangle.pass.cpp, but since the file is too large, phab folds it as a binary file :-(

[zsrkmyn]

Update match function

[aaron.ballman]

In D122530#3410157, @zsrkmyn wrote:

In D122530#3410074, @aaron.ballman wrote:

Thank you for this! It looks correct to me, but the changes should probably come with some test coverage as well.

There are actually some tests in libcxxabi/test/test_demangle.pass.cpp, but since the file is too large, phab folds it as a binary file :-(

Oh wow, I've never seen that happen before, thanks for letting me know!

[aaron.ballman]

LGTM! Please be sure to wait for someone from libcxxabi to approve before landing, though.

[urnathan]

In D122530#3410157, @zsrkmyn wrote:

In D122530#3410074, @aaron.ballman wrote:

Thank you for this! It looks correct to me, but the changes should probably come with some test coverage as well.

There are actually some tests in libcxxabi/test/test_demangle.pass.cpp, but since the file is too large, phab folds it as a binary file :-(

yeah, that's getting problematic. I wonder if we should break out all the testcases to a set of files in a subdir that the testprogram reads?

[erichkeane]

I wonder if there is value, for backwards compatibility to ALSO parse the old _ExtInt mangling?

[urnathan]

libcxxabi/src/demangle/ItaniumDemangle.h

498–500

Now that D120905 is landed please reword this as

OB += "_BitInt";
OB.printOpen();
Size->printAsOperand(OB);
OB.printClose();

(See NoexceptSpec as an example). This will handle parens inside Size if this is inside template arg list.

[zsrkmyn]

In D122530#3411232, @erichkeane wrote:

I wonder if there is value, for backwards compatibility to ALSO parse the old _ExtInt mangling?

@erichkeane, I'm not sure what _ExtInt was mangled to in the past, but it now is also mangled as DB/DU using the latest clang, so it's enough to demangle DB and DU IMO.

$ echo 'int foo(_ExtInt(3), unsigned _ExtInt(5)) {}' | ./builds/dev/bin/clang -S -emit-llvm -xc++ - -o - 2>/dev/null | grep '^define'
define dso_local noundef i32 @_Z3fooDB3_DU5_(i3 noundef signext %0, i5 noundef zeroext %1) #0 {

@aaron.ballman, I also uploaded the test as a small diff using the web interface (instead of the whole file uploaded by arc), so we can see the test change now :-)

libcxxabi/src/demangle/ItaniumDemangle.h

498–500

Done. Thanks!

[erichkeane]

In D122530#3411449, @zsrkmyn wrote:

In D122530#3411232, @erichkeane wrote:

I wonder if there is value, for backwards compatibility to ALSO parse the old _ExtInt mangling?

@erichkeane, I'm not sure what _ExtInt was mangled to in the past, but it now is also mangled as DB/DU using the latest clang, so it's enough to demangle DB and DU IMO.

I went to look it up, we used to mangle it as a 'struct', so it demangled anyway (so _ExtInt13 was : U7_ExtIntILi13, so void foo(_ExtInt(13)) was _Z3fooU7_ExtIntILi13EEi.

$ echo 'int foo(_ExtInt(3), unsigned _ExtInt(5)) {}' | ./builds/dev/bin/clang -S -emit-llvm -xc++ - -o - 2>/dev/null | grep '^define'
define dso_local noundef i32 @_Z3fooDB3_DU5_(i3 noundef signext %0, i5 noundef zeroext %1) #0 {

@aaron.ballman, I also uploaded the test as a small diff using the web interface (instead of the whole file uploaded by arc), so we can see the test change now :-)

[zsrkmyn]

In D122530#3411466, @erichkeane wrote:

In D122530#3411449, @zsrkmyn wrote:

In D122530#3411232, @erichkeane wrote:

I wonder if there is value, for backwards compatibility to ALSO parse the old _ExtInt mangling?

@erichkeane, I'm not sure what _ExtInt was mangled to in the past, but it now is also mangled as DB/DU using the latest clang, so it's enough to demangle DB and DU IMO.

I went to look it up, we used to mangle it as a 'struct', so it demangled anyway (so _ExtInt13 was : U7_ExtIntILi13, so void foo(_ExtInt(13)) was _Z3fooU7_ExtIntILi13EEi.

Thanks for explaination! So we don't need to make changes, right?

[erichkeane]

In D122530#3411497, @zsrkmyn wrote:

In D122530#3411466, @erichkeane wrote:

In D122530#3411449, @zsrkmyn wrote:

In D122530#3411232, @erichkeane wrote:

I wonder if there is value, for backwards compatibility to ALSO parse the old _ExtInt mangling?

@erichkeane, I'm not sure what _ExtInt was mangled to in the past, but it now is also mangled as DB/DU using the latest clang, so it's enough to demangle DB and DU IMO.

I went to look it up, we used to mangle it as a 'struct', so it demangled anyway (so _ExtInt13 was : U7_ExtIntILi13, so void foo(_ExtInt(13)) was _Z3fooU7_ExtIntILi13EEi.

Thanks for explaination! So we don't need to make changes, right?

Correct, I don't believe so. Sorry for the distraction/digression.

[zsrkmyn]

@ldionne, may I get your comments or approval? Thanks!

[zsrkmyn]

A soft ping.

@urnathan @ldionne, may I get your comments or approval? Thanks!

[urnathan]

looks good. You'll need to adjust for the ItaniumNodes.def file replacing FOR_EACH_NODE macro, but that'll be obvious.

[zsrkmyn]

Rebase to the latest commit

libcxxabi/src/demangle/ItaniumDemangle.h

public:
   template<typename Fn> void match(Fn F) const { F(Name); }
 
   StringView getName() const { return Name; }
   StringView getBaseName() const override { return Name; }
 
   void printLeft(OutputBuffer &OB) const override { OB += Name; }
 };
 
+class BitIntType final : public Node {
+  const Node *Size;
+  bool Signed;
+
+public:
+  BitIntType(const Node *Size_, bool Signed_)
+      : Node(KBitIntType), Size(Size_), Signed(Signed_) {}
+
+  template <typename Fn> void match(Fn F) const { F(Size, Signed); }
+
+  void printLeft(OutputBuffer &OB) const override {
+    if (!Signed)
+      OB += "unsigned ";
+    OB += "_BitInt";
+    OB.printOpen();
+    Size->printAsOperand(OB);
+    OB.printClose();
+  }
+};
+
 class ElaboratedTypeSpefType : public Node {
   StringView Kind;
   Node *Child;
 public:
   ElaboratedTypeSpefType(StringView Kind_, Node *Child_)
       : Node(KElaboratedTypeSpefType), Kind(Kind_), Child(Child_) {}
 
   template<typename Fn> void match(Fn F) const { F(Kind, Child); }
case 'F': {
       First += 2;
       Node *DimensionNumber = make<NameType>(parseNumber());
       if (!DimensionNumber)
         return nullptr;
       if (!consumeIf('_'))
         return nullptr;
       return make<BinaryFPType>(DimensionNumber);
     }
+    //                ::= DB <number> _                             # C23 signed _BitInt(N)
+    //                ::= DB <instantiation-dependent expression> _ # C23 signed _BitInt(N)
+    //                ::= DU <number> _                             # C23 unsigned _BitInt(N)
+    //                ::= DU <instantiation-dependent expression> _ # C23 unsigned _BitInt(N)
+    case 'B':
+    case 'U': {
+      bool Signed = look(1) == 'B';
+      First += 2;
+      Node *Size = std::isdigit(look()) ? make<NameType>(parseNumber())
+                                        : getDerived().parseExpr();
+      if (!Size)
+        return nullptr;
+      if (!consumeIf('_'))
+        return nullptr;
+      return make<BitIntType>(Size, Signed);
+    }
     //                ::= Di   # char32_t
     case 'i':
       First += 2;
       return make<NameType>("char32_t");
     //                ::= Ds   # char16_t
     case 's':
       First += 2;
       return make<NameType>("char16_t");

libcxxabi/src/demangle/ItaniumNodes.def

 NODE(QualifiedName)
 NODE(NestedName)
 NODE(LocalName)
 NODE(ModuleName)
 NODE(ModuleEntity)
 NODE(VectorType)
 NODE(PixelVectorType)
 NODE(BinaryFPType)
+NODE(BitIntType)
 NODE(SyntheticTemplateParamName)
 NODE(TypeTemplateParamDecl)
 NODE(NonTypeTemplateParamDecl)
 NODE(TemplateTemplateParamDecl)
 NODE(TemplateParamPackDecl)
 NODE(ParameterPack)
 NODE(TemplateArgumentPack)
 NODE(ParameterPackExpansion)

libcxxabi/test/test_demangle.pass.cpp

 // Is long double fp128?
 #define LDBL_FP128 (__LDBL_MANT_DIG__ == 113)
 
 const char* cases[][2] =
 {
     {"_Z1A", "A"},
     {"_Z1Av", "A()"},
     {"_Z1A1B1C", "A(B, C)"},
+    {"_Z1fDB3_", "f(_BitInt(3))"},
+    {"_Z1fDU10_", "f(unsigned _BitInt(10))"},
+    {"_Z1fIfEvDUstPT__", "void f<float>(unsigned _BitInt(sizeof (float*)))"},
+    {"_Z1fIiEvDBstPT__", "void f<int>(_BitInt(sizeof (int*)))"},
     {"_Z4testI1A1BE1Cv", "C test<A, B>()"},
     {"_Z4testI1A1BET0_T_S3_", "B test<A, B>(A, A)"},
     {"_ZN1SgtEi", "S::operator>(int)"},
     {"_ZrsI1QEiT_i", "int operator>><Q>(Q, int)"},
     {"_ZN13dyldbootstrap5startEPK12macho_headeriPPKcl", "dyldbootstrap::start(macho_header const*, int, char const**, long)"},
     {"_ZN4dyld17getExecutablePathEv", "dyld::getExecutablePath()"},
     {"_ZN4dyld22mainExecutablePreboundEv", "dyld::mainExecutablePrebound()"},
     {"_ZN4dyld14mainExecutableEv", "dyld::mainExecutable()"},

llvm/include/llvm/Demangle/ItaniumDemangle.h

public:
   template<typename Fn> void match(Fn F) const { F(Name); }
 
   StringView getName() const { return Name; }
   StringView getBaseName() const override { return Name; }
 
   void printLeft(OutputBuffer &OB) const override { OB += Name; }
 };
 
+class BitIntType final : public Node {
+  const Node *Size;
+  bool Signed;
+
+public:
+  BitIntType(const Node *Size_, bool Signed_)
+      : Node(KBitIntType), Size(Size_), Signed(Signed_) {}
+
+  template <typename Fn> void match(Fn F) const { F(Size, Signed); }
+
+  void printLeft(OutputBuffer &OB) const override {
+    if (!Signed)
+      OB += "unsigned ";
+    OB += "_BitInt";
+    OB.printOpen();
+    Size->printAsOperand(OB);
+    OB.printClose();
+  }
+};
+
 class ElaboratedTypeSpefType : public Node {
   StringView Kind;
   Node *Child;
 public:
   ElaboratedTypeSpefType(StringView Kind_, Node *Child_)
       : Node(KElaboratedTypeSpefType), Kind(Kind_), Child(Child_) {}
 
   template<typename Fn> void match(Fn F) const { F(Kind, Child); }
case 'F': {
       First += 2;
       Node *DimensionNumber = make<NameType>(parseNumber());
       if (!DimensionNumber)
         return nullptr;
       if (!consumeIf('_'))
         return nullptr;
       return make<BinaryFPType>(DimensionNumber);
     }
+    //                ::= DB <number> _                             # C23 signed _BitInt(N)
+    //                ::= DB <instantiation-dependent expression> _ # C23 signed _BitInt(N)
+    //                ::= DU <number> _                             # C23 unsigned _BitInt(N)
+    //                ::= DU <instantiation-dependent expression> _ # C23 unsigned _BitInt(N)
+    case 'B':
+    case 'U': {
+      bool Signed = look(1) == 'B';
+      First += 2;
+      Node *Size = std::isdigit(look()) ? make<NameType>(parseNumber())
+                                        : getDerived().parseExpr();
+      if (!Size)
+        return nullptr;
+      if (!consumeIf('_'))
+        return nullptr;
+      return make<BitIntType>(Size, Signed);
+    }
     //                ::= Di   # char32_t
     case 'i':
       First += 2;
       return make<NameType>("char32_t");
     //                ::= Ds   # char16_t
     case 's':
       First += 2;
       return make<NameType>("char16_t");

llvm/include/llvm/Demangle/ItaniumNodes.def

 NODE(QualifiedName)
 NODE(NestedName)
 NODE(LocalName)
 NODE(ModuleName)
 NODE(ModuleEntity)
 NODE(VectorType)
 NODE(PixelVectorType)
 NODE(BinaryFPType)
+NODE(BitIntType)
 NODE(SyntheticTemplateParamName)
 NODE(TypeTemplateParamDecl)
 NODE(NonTypeTemplateParamDecl)
 NODE(TemplateTemplateParamDecl)
 NODE(TemplateParamPackDecl)
 NODE(ParameterPack)
 NODE(TemplateArgumentPack)
 NODE(ParameterPackExpansion)