[dsymutil] Fix template stripping in getDIENames(...) to account for …

…overloaded operators

Currently dsymutil when generating accelerator tables will attempt to strip the template parameters from names for subroutines.
For some overload operators which contain < in their names e.g. operator< the current method ends up stripping the operator name as well,
we just end up with the name operator in the table for each case.

Differential Revision: https://reviews.llvm.org/D75545

llvm/lib/DWARFLinker/DWARFLinker.cpp

@@ -119,6 +119,37 @@ AddressesMap::~AddressesMap() {}
 
 DwarfEmitter::~DwarfEmitter() {}
 
+static Optional<StringRef> StripTemplateParameters(StringRef Name) {
+  // We are looking for template parameters to strip from Name. e.g.
+  //
+  //  operator<<B>
+  //
+  // We look for > at the end but if it does not contain any < then we
+  // have something like operator>>. We check for the operator<=> case.
+  if (!Name.endswith(">") || Name.count("<") == 0 || Name.endswith("<=>"))
+    return {};
+
+  // How many < until we have the start of the template parameters.
+  size_t NumLeftAnglesToSkip = 1;
+
+  // If we have operator<=> then we need to skip its < as well.
+  NumLeftAnglesToSkip += Name.count("<=>");
+
+  size_t RightAngleCount = Name.count('>');
+  size_t LeftAngleCount = Name.count('<');
+
+  // If we have more < than > we have operator< or operator<<
+  // we to account for their < as well.
+  if (LeftAngleCount > RightAngleCount)
+    NumLeftAnglesToSkip += LeftAngleCount - RightAngleCount;
+
+  size_t StartOfTemplate = 0;
+  while (NumLeftAnglesToSkip--)
+    StartOfTemplate = Name.find('<', StartOfTemplate) + 1;
+
+  return Name.substr(0, StartOfTemplate - 1);
+}
+
 bool DWARFLinker::DIECloner::getDIENames(const DWARFDie &Die,
                                          AttributesInfo &Info,
                                          OffsetsStringPool &StringPool,
@@ -140,10 +171,9 @@ bool DWARFLinker::DIECloner::getDIENames(const DWARFDie &Die,
       Info.Name = StringPool.getEntry(Name);
 
   if (StripTemplate && Info.Name && Info.MangledName != Info.Name) {
-    // FIXME: dsymutil compatibility. This is wrong for operator<
-    auto Split = Info.Name.getString().split('<');
-    if (!Split.second.empty())
-      Info.NameWithoutTemplate = StringPool.getEntry(Split.first);
+    StringRef Name = Info.Name.getString();
+    if (Optional<StringRef> StrippedName = StripTemplateParameters(Name))
+      Info.NameWithoutTemplate = StringPool.getEntry(*StrippedName);
   }
 
   return Info.Name || Info.MangledName;

llvm/test/tools/dsymutil/X86/template_operators.test

@@ -0,0 +1,62 @@
+RUN: dsymutil -oso-prepend-path %p/../Inputs %p/../Inputs/private/tmp/templated_operators/template_operators -o %t.apple.dSYM
+
+RUN: llvm-dwarfdump -apple-names %t.apple.dSYM | FileCheck %s -check-prefix=NAMES
+
+The test was compiled from a single source:
+$ cat template_operators.cpp
+template <typename T>
+bool operator<(const T&, const T&){
+ return true;
+}
+
+template <typename T>
+bool operator>(const T&, const T&){
+ return true;
+}
+
+template <typename T>
+bool operator<<(const T&, const T&){
+ return true;
+}
+
+template <typename T>
+bool operator>>(const T&, const T&){
+ return true;
+}
+
+template <typename T>
+bool operator==(const T&, const T&){
+ return true;
+}
+
+struct B{};
+
+struct D{};
+
+template <typename T>
+bool operator<=>(const T&,const T&){ return true;}
+
+int main() {
+  B b1;
+  B b2;
+  D d1;
+  D d2;
+
+   return b1 < b2 && b1 > b2 && b1 << b2 && b1 >> b2 && b1 == b2 && d1 <=> d2;
+}
+$ clang++ -std=c++2a -g template_operators.cpp -c -o template_operators.o
+$ clang template_operators.o -o template_operators
+
+
+NAMES-DAG: "operator<"
+NAMES-DAG: "operator<<B>"
+NAMES-DAG: "operator>"
+NAMES-DAG: "operator><B>"
+NAMES-DAG: "operator<<"
+NAMES-DAG: "operator<<<B>"
+NAMES-DAG: "operator>>"
+NAMES-DAG: "operator>><B>"
+NAMES-DAG: "operator<=>"
+NAMES-DAG: "operator<=><D>"
+NAMES-DAG: "operator=="
+NAMES-DAG: "operator==<B>"