[Lldb-commits] [PATCH] D17363: Add SymbolFilePDB with basic support for line tables.

Greg Clayton via lldb-commits lldb-commits at lists.llvm.org
Tue Mar 1 10:10:35 PST 2016

clayborg requested changes to this revision.
clayborg added a comment.
This revision now requires changes to proceed.

One general comment is the use of "auto". Although it makes the code shorter, it does make it quite a bit less readable. I will leave the decision to you since this is your code, but in general I think this is where auto is less than it is cracked up to be.

Comment at: source/Plugins/SymbolFile/PDB/SymbolFilePDB.cpp:282-285
@@ +281,6 @@
+SymbolFilePDB::ResolveSymbolContext(const lldb_private::FileSpec &file_spec, uint32_t line, bool check_inlines,
+                                    uint32_t resolve_scope, lldb_private::SymbolContextList &sc_list)
+    if (resolve_scope & lldb::eSymbolContextCompUnit)
So looking at SymbolFileDWARF::ResolveSymbolContext() I see it is very close to being SymbolFile agnostic... We would make SymbolFileDWARF::ResolveSymbolContext() into SymbolFile::ResolveSymbolContext() and clean it up to just use virtual SymbolFile calls. Then all SymbolFile plug-ins wouldn't need to implement this function. The basic flow of the function in DWARF is to iterate through all compile units. If check_inlines is true or the compile unit matches, grab the support files via lldb_private::CompileUnit::GetSupportFiles() and see if "file_spec" is in that support files list and find the one and only index for that file. If the index is valid, then get the LineTable from the compile unit via lldb_private::CompileUnit::GetLineTable(). Then find all matching entries. So with a quick refactor, all we need new SymbolFile instances to implement is GetSupportFiles() (which calls SymbolFile::ParseCompileUnitSupportFiles()) and CompileUnit::GetLineTable() (which calls into SymbolFile::ParseCompileUnitLineTable()). What do you think? This also helps others implementing new SymbolFile classes to not have to worry about the check_inlines thing.

Comment at: source/Plugins/SymbolFile/PDB/SymbolFilePDB.cpp:291-292
@@ +290,4 @@
+        // <vector>, either directly or indirectly.
+        auto compilands =
+            m_session_up->findCompilandsForSourceFile(file_spec.GetPath(), llvm::PDB_NameSearchFlags::NS_CaseInsensitive);
So if file_spec is "vector", this function will return all compile units that have line table entries that match "vector"? It doesn't seem like this is correct. If "check_inlines" is true, I would expect that you need to traverse all compilands?

Comment at: source/Plugins/SymbolFile/PDB/SymbolFilePDB.cpp:428-448
@@ +427,23 @@
+    auto found_cu = m_comp_units.find(id);
+    if (found_cu != m_comp_units.end())
+        return found_cu->second;
+    auto cu = m_session_up->getConcreteSymbolById<llvm::PDBSymbolCompiland>(id);
+    // `getSourceFileName` returns the basename of the original source file used to generate this compiland.  It does
+    // not return the full path.  Currently the only way to get that is to do a basename lookup to get the
+    // IPDBSourceFile, but this is ambiguous in the case of two source files with the same name contributing to the
+    // same compiland. This is a moderately extreme edge case, so we consider this ok for now, although we need to find
+    // a long term solution.
+    auto file = m_session_up->findOneSourceFile(cu.get(), cu->getSourceFileName(),
+                                                llvm::PDB_NameSearchFlags::NS_CaseInsensitive);
+    std::string path = file->getFileName();
+    lldb::LanguageType lang;
+    auto details = cu->findOneChild<llvm::PDBSymbolCompilandDetails>();
+    if (!details)
+        lang = lldb::eLanguageTypeC_plus_plus;
+    else
+        lang = TranslateLanguage(details->getLanguage());
"auto" really makes it hard to read this code to figure out what each variable actually is from someone that doesn't know the code. I will leave it up to you to do what you will with this, but this is where auto falls down for me. 


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