[lldb] Support simplified template names when looking up functions

This makes setting breakpoints work with -gsimple-template-names.

Assume that callers handle false positives. For example, `Module::LookupInfo::Prune` removes wrong template instantiations when setting a breakpoint.

Reviewed By: labath

Differential Revision: https://reviews.llvm.org/D137098

lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp

@@ -2389,6 +2389,24 @@ void SymbolFileDWARF::FindFunctions(const Module::LookupInfo &lookup_info,
       ResolveFunction(die, include_inlines, sc_list);
     return true;
   });
+  // With -gsimple-template-names, a templated type's DW_AT_name will not
+  // contain the template parameters. Try again stripping '<' and anything
+  // after, filtering out entries with template parameters that don't match.
+  {
+    const llvm::StringRef name_ref = name.GetStringRef();
+    auto it = name_ref.find('<');
+    if (it != llvm::StringRef::npos) {
+      const llvm::StringRef name_no_template_params = name_ref.slice(0, it);
+
+      Module::LookupInfo no_tp_lookup_info(lookup_info);
+      no_tp_lookup_info.SetLookupName(ConstString(name_no_template_params));
+      m_index->GetFunctions(no_tp_lookup_info, *this, parent_decl_ctx, [&](DWARFDIE die) {
+        if (resolved_dies.insert(die.GetDIE()).second)
+          ResolveFunction(die, include_inlines, sc_list);
+        return true;
+      });
+    }
+  }
 
   // Return the number of variable that were appended to the list
   const uint32_t num_matches = sc_list.GetSize() - original_size;

lldb/test/API/functionalities/breakpoint/cpp/TestCPPBreakpointLocations.py

@@ -12,7 +12,16 @@ class TestCPPBreakpointLocations(TestBase):
 
     @expectedFailureAll(oslist=["windows"], bugnumber="llvm.org/pr24764")
     def test(self):
-        self.build()
+        self.do_test(dict())
+
+    @expectedFailureAll(oslist=["windows"], bugnumber="llvm.org/pr24764")
+    @skipIf(compiler=no_match("clang"))
+    @skipIf(compiler_version=["<", "15.0"])
+    def test_simple_template_names(self):
+        self.do_test(dict(CFLAGS_EXTRAS="-gsimple-template-names"))
+
+    def do_test(self, debug_flags):
+        self.build(dictionary=debug_flags)
         self.breakpoint_id_tests()
 
     def verify_breakpoint_locations(self, target, bp_dict):
@@ -57,7 +66,11 @@ def breakpoint_id_tests(self):
 
             # Template cases
             {'name': 'func<float>', 'loc_names': []},
+            {'name': 'Foo::func<float>', 'loc_names': []},
+            {'name': 'ns::Foo::func<float>', 'loc_names': []},
             {'name': 'func<int>', 'loc_names': ['auto ns::Foo<double>::func<int>()']},
+            {'name': 'Foo<double>::func<int>', 'loc_names': ['auto ns::Foo<double>::func<int>()']},
+            {'name': 'ns::Foo<double>::func<int>', 'loc_names': ['auto ns::Foo<double>::func<int>()']},
             {'name': 'func', 'loc_names': ['auto ns::Foo<double>::func<int>()',
                                            'auto ns::Foo<double>::func<ns::Foo<int>>()']},
 
@@ -71,6 +84,15 @@ def breakpoint_id_tests(self):
             {'name': 'operator<<<int>', 'loc_names': ['void ns::Foo<double>::operator<<<int>(int)']},
             {'name': 'ns::Foo<double>::operator<<', 'loc_names': ['void ns::Foo<double>::operator<<<int>(int)',
                                                                   'void ns::Foo<double>::operator<<<ns::Foo<int>>(ns::Foo<int>)']},
+
+            {'name': 'g<float>', 'loc_names': []},
+            {'name': 'g<int>', 'loc_names': ['void ns::g<int>()']},
+            {'name': 'g<char>', 'loc_names': ['void ns::g<char>()']},
+            {'name': 'g', 'loc_names': ['void ns::g<int>()', 'void ns::g<char>()']},
+            {'name': 'ns::g<float>', 'loc_names': []},
+            {'name': 'ns::g<int>', 'loc_names': ['void ns::g<int>()']},
+            {'name': 'ns::g<char>', 'loc_names': ['void ns::g<char>()']},
+            {'name': 'ns::g', 'loc_names': ['void ns::g<int>()', 'void ns::g<char>()']},
         ]
 
         for bp_dict in bp_dicts:

lldb/test/API/functionalities/breakpoint/cpp/main.cpp

@@ -94,6 +94,8 @@ template <typename Type> struct Foo {
 
   template <typename T> void operator<<(T t) {}
 };
+
+template <typename Type> void g() {}
 } // namespace ns
 
 int main (int argc, char const *argv[])
@@ -123,5 +125,8 @@ int main (int argc, char const *argv[])
     f.operator<<(5);
     f.operator<< <ns::Foo<int>>({});
 
+    ns::g<int>();
+    ns::g<char>();
+
     return 0;
 }