[lldb] Don't process symlinks deep inside DWARFUnit

Summary:
This code is handling debug info paths starting with /proc/self/cwd,
which is one of the mechanisms people use to obtain "relocatable" debug
info (the idea being that one starts the debugger with an appropriate
cwd and things "just work").

Instead of resolving the symlinks inside DWARFUnit, we can do the same
thing more elegantly by hooking into the existing Module path remapping
code. Since llvm::DWARFUnit does not support any similar functionality,
doing things this way is also a step towards unifying llvm and lldb
dwarf parsers.

Reviewers: JDevlieghere, aprantl, clayborg, jdoerfert

Subscribers: lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D71770

2 files changed, 12 insertions, 20 deletions

diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.cpp b/lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.cpp
index a7df540ba56..fde6459b2c6 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.cpp
@@ -732,25 +732,6 @@ removeHostnameFromPathname(llvm::StringRef path_from_dwarf) {
   return path;
 }
 
-static FileSpec resolveCompDir(const FileSpec &path) {
-  bool is_symlink = SymbolFileDWARF::GetSymlinkPaths().FindFileIndex(
-                        0, path, /*full*/ true) != UINT32_MAX;
-
-  if (!is_symlink)
-    return path;
-
-  namespace fs = llvm::sys::fs;
-  if (fs::get_file_type(path.GetPath(), false) != fs::file_type::symlink_file)
-    return path;
-
-  FileSpec resolved_symlink;
-  const auto error = FileSystem::Instance().Readlink(path, resolved_symlink);
-  if (error.Success())
-    return resolved_symlink;
-
-  return path;
-}
-
 void DWARFUnit::ComputeCompDirAndGuessPathStyle() {
   m_comp_dir = FileSpec();
   const DWARFDebugInfoEntry *die = GetUnitDIEPtrOnly();
@@ -762,7 +743,7 @@ void DWARFUnit::ComputeCompDirAndGuessPathStyle() {
   if (!comp_dir.empty()) {
     FileSpec::Style comp_dir_style =
         FileSpec::GuessPathStyle(comp_dir).getValueOr(FileSpec::Style::native);
-    m_comp_dir = resolveCompDir(FileSpec(comp_dir, comp_dir_style));
+    m_comp_dir = FileSpec(comp_dir, comp_dir_style);
   } else {
     // Try to detect the style based on the DW_AT_name attribute, but just store
     // the detected style in the m_comp_dir field.
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
index 466d5ddd23d..9021cda4941 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
@@ -453,6 +453,17 @@ SymbolFileDWARF::GetTypeSystemForLanguage(LanguageType language) {
 void SymbolFileDWARF::InitializeObject() {
   Log *log = LogChannelDWARF::GetLogIfAll(DWARF_LOG_DEBUG_INFO);
 
+  Module &module = *GetObjectFile()->GetModule();
+
+  for (const FileSpec &symlink : GetSymlinkPaths()) {
+    FileSpec resolved;
+    Status status = FileSystem::Instance().Readlink(symlink, resolved);
+    if (status.Success())
+      module.GetSourceMappingList().Append(ConstString(symlink.GetPath()),
+                                           ConstString(resolved.GetPath()),
+                                           /*notify=*/true);
+  }
+
   if (!GetGlobalPluginProperties()->IgnoreFileIndexes()) {
     DWARFDataExtractor apple_names, apple_namespaces, apple_types, apple_objc;
     LoadSectionData(eSectionTypeDWARFAppleNames, apple_names);