[tsan] Prefer mangled name when looking up global variable declaration for racy address

[dcoughlin]

Summary

For Thread Sanitizer reports, LLDB tries to find a global variable declaration corresponding to the racy address in order to provide a filename and line number. This commit changes the lookup of the variable to use the mangled name for lookup and fall back to the demangled version if unavailable. This is needed to report locations of races on Swift global variables.

I've also added a test to make sure we look up C++ globals correctly.

[clayborg]

Looks good.

lldb/trunk/packages/Python/lldbsuite/test/functionalities/tsan/cpp_global_location/Makefile

+LEVEL = ../../../make
+
+CXX_SOURCES := main.cpp
+CFLAGS_EXTRAS := -fsanitize=thread -g
+
+include $(LEVEL)/Makefile.rules

lldb/trunk/packages/Python/lldbsuite/test/functionalities/tsan/cpp_global_location/TestTsanCPPGlobalLocation.py

+"""
+Tests that TSan correctly reports the filename and line number of a racy global C++ variable.
+"""
+
+import os, time
+import lldb
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test.decorators import *
+import lldbsuite.test.lldbutil as lldbutil
+import json
+
+class TsanCPPGlobalLocationTestCase(TestBase):
+
+    mydir = TestBase.compute_mydir(__file__)
+
+    @expectedFailureAll(oslist=["linux"], bugnumber="non-core functionality, need to reenable and fix later (DES 2014.11.07)")
+    @skipIfFreeBSD # llvm.org/pr21136 runtimes not yet available by default
+    @skipIfRemote
+    @skipUnlessCompilerRt
+    @skipUnlessThreadSanitizer
+    def test (self):
+        self.build ()
+        self.tsan_tests ()
+
+    def setUp(self):
+        # Call super's setUp().
+        TestBase.setUp(self)
+
+    def tsan_tests (self):
+        exe = os.path.join (os.getcwd(), "a.out")
+        self.expect("file " + exe, patterns = [ "Current executable set to .*a.out" ])
+
+        self.runCmd("run")
+
+        stop_reason = self.dbg.GetSelectedTarget().process.GetSelectedThread().GetStopReason()
+        if stop_reason == lldb.eStopReasonExec:
+            # On OS X 10.10 and older, we need to re-exec to enable interceptors.
+            self.runCmd("continue")
+
+        # the stop reason of the thread should be breakpoint.
+        self.expect("thread list", "A data race should be detected",
+            substrs = ['stopped', 'stop reason = Data race detected'])
+
+        self.expect("thread info -s", "The extended stop info should contain the TSan provided fields",
+            substrs = ["instrumentation_class", "description", "mops"])
+
+        output_lines = self.res.GetOutput().split('\n')
+        json_line = '\n'.join(output_lines[2:])
+        data = json.loads(json_line)
+        self.assertEqual(data["instrumentation_class"], "ThreadSanitizer")
+        self.assertEqual(data["issue_type"], "data-race")
+
+        self.assertTrue(data["location_filename"].endswith("/main.cpp"))
+        self.assertEqual(data["location_line"], line_number('main.cpp', '// global variable'))

lldb/trunk/packages/Python/lldbsuite/test/functionalities/tsan/cpp_global_location/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 <pthread.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+long my_global_variable;  // global variable
+
+void *f1(void *p) {
+    my_global_variable = 42;
+    return NULL;
+}
+
+void *f2(void *p) {
+    my_global_variable = 43;
+    return NULL;
+}
+
+int main (int argc, char const *argv[])
+{
+    pthread_t t1;
+    pthread_create(&t1, NULL, f1, NULL);
+
+    pthread_t t2;
+    pthread_create(&t2, NULL, f2, NULL);
+
+    pthread_join(t1, NULL);
+    pthread_join(t2, NULL);
+
+    return 0;
+}

lldb/trunk/source/Plugins/InstrumentationRuntime/ThreadSanitizer/ThreadSanitizerRuntime.cpp

GetSymbolDeclarationFromAddress(ProcessSP process_sp, addr_t addr, Declaration &decl)
     lldb_private::Address so_addr;
     if (! process_sp->GetTarget().GetSectionLoadList().ResolveLoadAddress(addr, so_addr))
         return;
     
     lldb_private::Symbol *symbol = so_addr.CalculateSymbolContextSymbol();
     if (! symbol)
         return;
     
-    ConstString sym_name = symbol->GetName();
+    ConstString sym_name = symbol->GetMangled().GetName(lldb::eLanguageTypeUnknown, Mangled::ePreferMangled);
     
     ModuleSP module = symbol->CalculateSymbolContextModule();
     if (! module)
         return;
     
     VariableList var_list;
     module->FindGlobalVariables(sym_name, nullptr, true, 1U, var_list);
     if (var_list.GetSize() < 1)