Fix MinidumpParser::GetFilteredModuleList() and test it

The MinidumpParser::GetFilteredModuleList() code was attempting to iterate through the entire module list and if it found more than one entry for a given module name, it wanted to pick the MinidumpModule with the lowest address. A bug existed where it wasn't doing that due to "exists" variable being inverted. "exists" was set to true if it was inserted, not if it existed. Furthermore, the order of the modules would be modified by sorting all modules from low address to high address (using MinidumpModule::base_of_image). This fix also maintains the original order which means your executable is at index 0 as intended instead of some random shared library.

Tests were added to ensure this functionality doesn't regress.

Differential Revision: https://reviews.llvm.org/D55614

llvm-svn: 349062

diff --git a/lldb/source/Plugins/Process/minidump/MinidumpParser.cpp b/lldb/source/Plugins/Process/minidump/MinidumpParser.cpp
index 6b94d4fede32790bea756dadf3e2fd218c92b681..adaa01c76d36b174fc3d38bfc90133d2de91c452 100644 (file)
--- a/lldb/source/Plugins/Process/minidump/MinidumpParser.cpp
+++ b/lldb/source/Plugins/Process/minidump/MinidumpParser.cpp
@@ -274,36 +274,45 @@ llvm::ArrayRef<MinidumpModule> MinidumpParser::GetModuleList() {
 
 std::vector<const MinidumpModule *> MinidumpParser::GetFilteredModuleList() {
   llvm::ArrayRef<MinidumpModule> modules = GetModuleList();
-  // map module_name -> pair(load_address, pointer to module struct in memory)
-  llvm::StringMap<std::pair<uint64_t, const MinidumpModule *>> lowest_addr;
+  // map module_name -> filtered_modules index
+  typedef llvm::StringMap<size_t> MapType;
+  MapType module_name_to_filtered_index;
 
   std::vector<const MinidumpModule *> filtered_modules;
-
+  
   llvm::Optional<std::string> name;
   std::string module_name;
 
   for (const auto &module : modules) {
     name = GetMinidumpString(module.module_name_rva);
-
+    
     if (!name)
       continue;
-
+    
     module_name = name.getValue();
-
-    auto iter = lowest_addr.end();
-    bool exists;
-    std::tie(iter, exists) = lowest_addr.try_emplace(
-        module_name, std::make_pair(module.base_of_image, &module));
-
-    if (exists && module.base_of_image < iter->second.first)
-      iter->second = std::make_pair(module.base_of_image, &module);
-  }
-
-  filtered_modules.reserve(lowest_addr.size());
-  for (const auto &module : lowest_addr) {
-    filtered_modules.push_back(module.second.second);
+    
+    MapType::iterator iter;
+    bool inserted;
+    // See if we have inserted this module aready into filtered_modules. If we
+    // haven't insert an entry into module_name_to_filtered_index with the
+    // index where we will insert it if it isn't in the vector already.
+    std::tie(iter, inserted) = module_name_to_filtered_index.try_emplace(
+        module_name, filtered_modules.size());
+
+    if (inserted) {
+      // This module has not been seen yet, insert it into filtered_modules at
+      // the index that was inserted into module_name_to_filtered_index using
+      // "filtered_modules.size()" above.
+      filtered_modules.push_back(&module);
+    } else {
+      // This module has been seen. Modules are sometimes mentioned multiple
+      // times when they are mapped discontiguously, so find the module with
+      // the lowest "base_of_image" and use that as the filtered module.
+      auto dup_module = filtered_modules[iter->second];
+      if (module.base_of_image < dup_module->base_of_image)
+        filtered_modules[iter->second] = &module;
+    }
   }
-
   return filtered_modules;
 }
 

diff --git a/lldb/unittests/Process/minidump/Inputs/modules-dup-min-addr.dmp b/lldb/unittests/Process/minidump/Inputs/modules-dup-min-addr.dmp
new file mode 100644 (file)
index 0000000..a7a1c4a
Binary files /dev/null and b/lldb/unittests/Process/minidump/Inputs/modules-dup-min-addr.dmp differ

diff --git a/lldb/unittests/Process/minidump/Inputs/modules-order.dmp b/lldb/unittests/Process/minidump/Inputs/modules-order.dmp
new file mode 100644 (file)
index 0000000..cab926b
Binary files /dev/null and b/lldb/unittests/Process/minidump/Inputs/modules-order.dmp differ

diff --git a/lldb/unittests/Process/minidump/MinidumpParserTest.cpp b/lldb/unittests/Process/minidump/MinidumpParserTest.cpp
index 57f27d4f6ba342d231f393ea094ff69f58e84f6c..7508cf23654655d4eb78ae1aecd02e9d23d57e68 100644 (file)
--- a/lldb/unittests/Process/minidump/MinidumpParserTest.cpp
+++ b/lldb/unittests/Process/minidump/MinidumpParserTest.cpp
@@ -533,3 +533,41 @@ TEST_F(MinidumpParserTest, ConvertMinidumpContext_x86_32_wow64) {
     }
   }
 }
+
+TEST_F(MinidumpParserTest, MinidumpDuplicateModuleMinAddress) {
+  SetUpData("modules-dup-min-addr.dmp");
+  // Test that if we have two modules in the module list:
+  //    /tmp/a with range [0x2000-0x3000)
+  //    /tmp/a with range [0x1000-0x2000)
+  // That we end up with one module in the filtered list with the
+  // range [0x1000-0x2000). MinidumpParser::GetFilteredModuleList() is
+  // trying to ensure that if we have the same module mentioned more than
+  // one time, we pick the one with the lowest base_of_image.
+  std::vector<const MinidumpModule *> filtered_modules =
+      parser->GetFilteredModuleList();
+  EXPECT_EQ(1, filtered_modules.size());
+  EXPECT_EQ(0x0000000000001000, filtered_modules[0]->base_of_image);
+}
+
+TEST_F(MinidumpParserTest, MinidumpModuleOrder) {
+  SetUpData("modules-order.dmp");
+  // Test that if we have two modules in the module list:
+  //    /tmp/a with range [0x2000-0x3000)
+  //    /tmp/b with range [0x1000-0x2000)
+  // That we end up with two modules in the filtered list with the same ranges
+  // and in the same order. Previous versions of the
+  // MinidumpParser::GetFilteredModuleList() function would sort all images
+  // by address and modify the order of the modules.
+  std::vector<const MinidumpModule *> filtered_modules =
+      parser->GetFilteredModuleList();
+  llvm::Optional<std::string> name;
+  EXPECT_EQ(2, filtered_modules.size());
+  EXPECT_EQ(0x0000000000002000, filtered_modules[0]->base_of_image);
+  name = parser->GetMinidumpString(filtered_modules[0]->module_name_rva);
+  ASSERT_TRUE((bool)name);
+  EXPECT_EQ(std::string("/tmp/a"), *name);
+  EXPECT_EQ(0x0000000000001000, filtered_modules[1]->base_of_image);
+  name = parser->GetMinidumpString(filtered_modules[1]->module_name_rva);
+  ASSERT_TRUE((bool)name);
+  EXPECT_EQ(std::string("/tmp/b"), *name);
+}