[DWARF] Generate qualified names of functions if linkage names are missing.

[sivachandra]

Summary

This is similar to the change introduced for variable DIEs in r233098. If the
linkage names of functions are missing in the DWARF, then their fully qualified
names (similar to the name that would be got by demangling their linkage name)
is generated using the decl context.

This change fixes TestNamespace when the test case is compiled with GCC, hence
it is enabled for GCC. The test and the test case are also enhanced to cover
variadic functions.

[clayborg]

Looks good.

source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp

if (die->GetDIENamesAndRanges (this,
                 func_range.SetByteSize(highest_func_addr - lowest_func_addr);
         }
 
         if (func_range.GetBaseAddress().IsValid())
         {
             Mangled func_name;
             if (mangled)
                 func_name.SetValue(ConstString(mangled), true);
-            else if (name)
+            else if (die->GetParent()->Tag() == DW_TAG_compile_unit &&
+                     LanguageRuntime::LanguageIsCPlusPlus(dwarf_cu->GetLanguageType()) &&
+                     strcmp(name, "main") != 0)
+            {
+                // If the mangled name is not present in the DWARF, generate the demangled name
+                // using the decl context. We skip if the function is "main" as its name is
+                // never mangled.
+                bool is_static = false;
+                bool is_variadic = false;
+                unsigned type_quals = 0;
+                std::vector<ClangASTType> param_types;
+                std::vector<clang::ParmVarDecl*> param_decls;
+                const DWARFDebugInfoEntry *decl_ctx_die = NULL;
+                DWARFDeclContext decl_ctx;
+                StreamString sstr;
+
+                die->GetDWARFDeclContext(this, dwarf_cu, decl_ctx);
+                sstr << decl_ctx.GetQualifiedName();
+
+                clang::DeclContext *containing_decl_ctx = GetClangDeclContextContainingDIE(dwarf_cu,
+                                                                                           die,
+                                                                                           &decl_ctx_die);
+                ParseChildParameters(sc,
+                                     containing_decl_ctx,
+                                     dwarf_cu,
+                                     die,
+                                     true,
+                                     is_static,
+                                     is_variadic,
+                                     param_types,
+                                     param_decls,
+                                     type_quals);
+                sstr << "(";
+                for (size_t i = 0; i < param_types.size(); i++)
+                {
+                    if (i > 0)
+                        sstr << ", ";
+                    sstr << param_types[i].GetTypeName();
+                }
+                if (is_variadic)
+                    sstr << ", ...";
+                sstr << ")";
+                if (type_quals & clang::Qualifiers::Const)
+                    sstr << " const";
+
+                func_name.SetValue(ConstString(sstr.GetData()), false);
+            }
+            else
                 func_name.SetValue(ConstString(name), false);
 
             FunctionSP func_sp;
             std::unique_ptr<Declaration> decl_ap;
             if (decl_file != 0 || decl_line != 0 || decl_column != 0)
                 decl_ap.reset(new Declaration (sc.comp_unit->GetSupportFiles().GetFileSpecAtIndex(decl_file), 
                                                decl_line, 
                                                decl_column));

test/lang/cpp/namespace/TestNamespace.py

class NamespaceTestCase(TestBase):
     @unittest2.skipUnless(sys.platform.startswith("darwin"), "requires Darwin")
     @dsym_test
     def test_with_dsym_and_run_command(self):
         """Test that anonymous and named namespace variables display correctly."""
         self.buildDsym()
         self.namespace_variable_commands()
 
     # rdar://problem/8668674
-    @expectedFailureGcc # llvm.org/pr15302: lldb does not print 'anonymous namespace' when the inferior is built with GCC (4.7)
     @dwarf_test
     def test_with_dwarf_and_run_command(self):
         """Test that anonymous and named namespace variables display correctly."""
         self.buildDwarf()
         self.namespace_variable_commands()
 
     def setUp(self):
         # Call super's setUp().
def namespace_variable_commands(self):
 
         # global namespace qualification with function in anonymous namespace
         self.expect("expression -- ::myanonfunc(4)",
             patterns = [' = 8'])
 
         self.expect("p myanonfunc",
             patterns = ['\(anonymous namespace\)::myanonfunc\(int\)'])
 
+        self.expect("p variadic_sum",
+            patterns = ['\(anonymous namespace\)::variadic_sum\(int, ...\)'])
+
 if __name__ == '__main__':
     import atexit
     lldb.SBDebugger.Initialize()
     atexit.register(lambda: lldb.SBDebugger.Terminate())
     unittest2.main()

test/lang/cpp/namespace/main.cpp

 //===-- main.cpp ------------------------------------------------*- C++ -*-===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 
+#include <cstdarg>
+
 namespace {
     typedef unsigned int my_uint_t;
     int i; // Find the line number for anonymous namespace variable i.
 
     int myanonfunc (int a)
     {
         return a + a;
     }
+
+    int
+    variadic_sum (int arg_count...)
+    {
+        int sum = 0;
+        va_list args;
+        va_start(args, arg_count);
+
+        for (int i = 0; i < arg_count; i++)
+            sum += va_arg(args, int);
+
+        va_end(args);
+        return sum;
+    }
 }
 
 namespace A {
     typedef unsigned int uint_t;
     namespace B {
         typedef unsigned int uint_t;
         int j; // Find the line number for named namespace variable j.
         int myfunc (int a);
int Foo::myfunc(int a)
     ::my_uint_t anon_uint = 0;
     A::uint_t a_uint = 1;
     B::uint_t b_uint = 2;
     Y::uint_t y_uint = 3;
     i = 3;
     j = 4;
     printf("::i=%d\n", ::i);
     printf("A::B::j=%d\n", A::B::j);
+    printf("variadic_sum=%d\n", variadic_sum(3, 1, 2, 3));
     myanonfunc(3);
     return myfunc2(3) + j + i + a + 2 + anon_uint + a_uint + b_uint + y_uint; // Set break point at this line.
 }
 
 int
 main (int argc, char const *argv[])
 {
     return Foo::myfunc(12);
 }