PDB support of function-level linking and splitted functions

Summary:
The patch adds support of splitted functions (when MSVC is used with PGO) and function-level linking feature.

SymbolFilePDB::ParseCompileUnitLineTable function relies on fact that ranges of compiled source files in the binary are continuous and don't intersect each other. The function creates LineSequence for each file and inserts it into LineTable, and implementation of last one relies on continuity of the sequence. But it's not always true when function-level linking enabled, e.g. in added input test file test-pdb-function-level-linking.exe there is xstring's std__basic_string_char_std__char_traits_char__std__allocator_char_____max_size (.00454820) between test-pdb-function-level-linking.cpp's foo (.00454770) and main (.004548F0).

To fix the problem this patch renews the sequence on each address gap.

Reviewers: asmith, zturner

Reviewed By: asmith

Subscribers: mgorny, lldb-commits

Differential Revision: https://reviews.llvm.org/D47708

llvm-svn: 334030

lldb/source/Plugins/SymbolFile/PDB/SymbolFilePDB.cpp

@@ -1571,6 +1571,9 @@ bool SymbolFilePDB::ParseCompileUnitLineTable(
         line_table->AppendLineEntryToSequence(
             sequence.get(), prev_addr + prev_length, prev_line, 0,
             prev_source_idx, false, false, false, false, true);
+
+        line_table->InsertSequence(sequence.release());
+        sequence.reset(line_table->CreateLineSequenceContainer());
       }
 
       if (ShouldAddLine(match_line, lno, length)) {

lldb/unittests/SymbolFile/PDB/CMakeLists.txt

@@ -17,6 +17,10 @@ add_lldb_unittest(SymbolFilePDBTests
 set(test_inputs
    test-pdb.exe
    test-pdb.pdb
+   test-pdb-function-level-linking.exe
+   test-pdb-function-level-linking.pdb
+   test-pdb-splitted-function.exe
+   test-pdb-splitted-function.pdb
    test-pdb-types.exe
    test-pdb-types.pdb)
 

lldb/unittests/SymbolFile/PDB/Inputs/test-pdb-function-level-linking.cpp

@@ -0,0 +1,17 @@
+// Compile with "cl /c /ZI /sdl /EHsc /MTd /permissive-
+// test-pdb-function-level-linking.cpp"
+// Link with "link /debug:full test-pdb-function-level-linking.obj"
+
+#include <memory>
+#include <string>
+
+std::string foo()
+{
+    return "Hello!";
+}
+
+int main()
+{
+    auto x = foo();
+    return 0;
+}

lldb/unittests/SymbolFile/PDB/Inputs/test-pdb-splitted-function.cpp

@@ -0,0 +1,27 @@
+// Compile with "cl /c /Zi /GL /O2 /EHsc /MTd test-pdb-splitted-function.cpp"
+// Link with "link /debug:full /LTCG /GENPROFILE
+//   test-pdb-splitted-function.obj"
+// Run several times
+// Link with "link /debug:full /LTCG /USEPROFILE
+//   test-pdb-splitted-function.obj"
+
+#include <cmath>
+#include <iostream>
+
+int main()
+{
+    auto b = false;
+    for (auto i = 1; i <= 1024; i++)
+    {
+        if (b)
+        {
+            std::cout << "Unreachable code" << std::endl;
+            auto x = std::sin(i);
+            return x;
+        }
+
+        b = (i % 2 + (i - 1) % 2) != 1;
+    }
+
+    return 0;
+}

lldb/unittests/SymbolFile/PDB/SymbolFilePDBTests.cpp

@@ -56,6 +56,10 @@ class SymbolFilePDBTests : public testing::Test {
     SymbolFilePDB::Initialize();
 
     m_pdb_test_exe = GetInputFilePath("test-pdb.exe");
+    m_function_level_linking_test_exe =
+        GetInputFilePath("test-pdb-function-level-linking.exe");
+    m_splitted_function_test_exe =
+        GetInputFilePath("test-pdb-splitted-function.exe");
     m_types_test_exe = GetInputFilePath("test-pdb-types.exe");
   }
 
@@ -73,6 +77,8 @@ class SymbolFilePDBTests : public testing::Test {
 
 protected:
   std::string m_pdb_test_exe;
+  std::string m_function_level_linking_test_exe;
+  std::string m_splitted_function_test_exe;
   std::string m_types_test_exe;
 
   bool FileSpecMatchesAsBaseOrFull(const FileSpec &left,
@@ -354,6 +360,56 @@ TEST_F(SymbolFilePDBTests, TestLineTablesMatchSpecific) {
   VerifyLineEntry(module, sc, header1, *lt, 9, 0x401090);
 }
 
+void TestLineTableConsistency(llvm::StringRef exe_path, llvm::StringRef source_name)
+{
+  // All line entries of compile unit's line table must be consistent
+  // even if compiled sources are not continuous in the binary file.
+  FileSpec fspec(exe_path, false);
+  ArchSpec aspec("i686-pc-windows");
+  lldb::ModuleSP module = std::make_shared<Module>(fspec, aspec);
+  SymbolVendor *plugin = module->GetSymbolVendor();
+  SymbolFile *symfile = plugin->GetSymbolFile();
+  FileSpec source_file(source_name, false);
+  uint32_t scope = lldb::eSymbolContextCompUnit | lldb::eSymbolContextLineEntry;
+  SymbolContextList sc_list;
+  uint32_t count =
+      symfile->ResolveSymbolContext(source_file, 0, true, scope, sc_list);
+  EXPECT_EQ(1u, count);
+
+  SymbolContext sc;
+  EXPECT_TRUE(sc_list.GetContextAtIndex(0, sc));
+
+  LineTable *lt = sc.comp_unit->GetLineTable();
+  EXPECT_NE(nullptr, lt);
+
+  count = lt->GetSize();
+  EXPECT_LT(0u, count);
+
+  LineEntry le;
+  EXPECT_TRUE(lt->GetLineEntryAtIndex(0, le));
+  for (int i = 1; i < count; i++)
+  {
+    lldb::addr_t curr_end =
+        le.range.GetBaseAddress().GetFileAddress() + le.range.GetByteSize();
+
+    EXPECT_TRUE(lt->GetLineEntryAtIndex(i, le));
+
+    EXPECT_LE(curr_end, le.range.GetBaseAddress().GetFileAddress());
+  }
+}
+
+TEST_F(SymbolFilePDBTests, TestFunctionLevelLinking) {
+  TestLineTableConsistency(
+      m_function_level_linking_test_exe,
+      "test-pdb-function-level-linking.cpp");
+}
+
+TEST_F(SymbolFilePDBTests, TestSplittedFunction) {
+  TestLineTableConsistency(
+      m_splitted_function_test_exe,
+      "test-pdb-splitted-function.cpp");
+}
+
 TEST_F(SymbolFilePDBTests, TestSimpleClassTypes) {
   FileSpec fspec(m_types_test_exe.c_str(), false);
   ArchSpec aspec("i686-pc-windows");