Commit 27df2d9f authored by Pavel Labath's avatar Pavel Labath
Browse files

[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
parent 9a3ff478

lldb/include/lldb/Core/Module.h

+5 −4
Original line number Diff line number Diff line
@@ -10,6 +10,7 @@ 
#define liblldb_Module_h_



#include "lldb/Core/Address.h"

#include "lldb/Core/ModuleList.h"

#include "lldb/Core/ModuleSpec.h"

#include "lldb/Symbol/ObjectFile.h"

#include "lldb/Symbol/SymbolContextScope.h"
@@ -966,10 +967,10 @@ protected: 
  ///references to them

  TypeSystemMap m_type_system_map;   ///< A map of any type systems associated

                                     ///with this module

  PathMappingList m_source_mappings; ///< Module specific source remappings for

                                     ///when you have debug info for a module

                                     ///that doesn't match where the sources

                                     ///currently are

  /// Module specific source remappings for when you have debug info for a

  /// module that doesn't match where the sources currently are.

  PathMappingList m_source_mappings =

      ModuleList::GetGlobalModuleListProperties().GetSymlinkMappings();

  lldb::SectionListUP m_sections_up; ///< Unified section list for module that

                                     /// is used by the ObjectFile and and

                                     /// ObjectFile instances for the debug info

lldb/include/lldb/Core/ModuleList.h

+8 −0
Original line number Diff line number Diff line
@@ -20,6 +20,7 @@ 
#include "lldb/lldb-types.h"



#include "llvm/ADT/DenseSet.h"

#include "llvm/Support/RWMutex.h"



#include <functional>

#include <list>
@@ -46,6 +47,11 @@ class UUID; 
class VariableList;



class ModuleListProperties : public Properties {

  mutable llvm::sys::RWMutex m_symlink_paths_mutex;

  PathMappingList m_symlink_paths;



  void UpdateSymlinkMappings();



public:

  ModuleListProperties();
@@ -53,6 +59,8 @@ public: 
  bool SetClangModulesCachePath(llvm::StringRef path);

  bool GetEnableExternalLookup() const;

  bool SetEnableExternalLookup(bool new_value);



  PathMappingList GetSymlinkMappings() const;

};



/// \class ModuleList ModuleList.h "lldb/Core/ModuleList.h"

lldb/packages/Python/lldbsuite/test/functionalities/breakpoint/comp_dir_symlink/TestCompDirSymLink.py

+9 −12
Original line number Diff line number Diff line
@@ -12,7 +12,7 @@ from lldbsuite.test import lldbutil 


_EXE_NAME = 'CompDirSymLink'  # Must match Makefile

_SRC_FILE = 'relative.cpp'

_COMP_DIR_SYM_LINK_PROP = 'plugin.symbol-file.dwarf.comp-dir-symlink-paths'

_COMP_DIR_SYM_LINK_PROP = 'symbols.debug-info-symlink-paths'





class CompDirSymLinkTestCase(TestBase):
@@ -30,10 +30,7 @@ class CompDirSymLinkTestCase(TestBase): 
    @skipIf(hostoslist=["windows"])

    def test_symlink_paths_set(self):

        pwd_symlink = self.create_src_symlink()

        self.doBuild(pwd_symlink)

        self.runCmd(

            "settings set %s %s" %

            (_COMP_DIR_SYM_LINK_PROP, pwd_symlink))

        self.doBuild(pwd_symlink, pwd_symlink)

        src_path = self.getBuildArtifact(_SRC_FILE)

        lldbutil.run_break_set_by_file_and_line(self, src_path, self.line)
@@ -41,10 +38,7 @@ class CompDirSymLinkTestCase(TestBase): 
    def test_symlink_paths_set_procselfcwd(self):

        os.chdir(self.getBuildDir())

        pwd_symlink = '/proc/self/cwd'

        self.doBuild(pwd_symlink)

        self.runCmd(

            "settings set %s %s" %

            (_COMP_DIR_SYM_LINK_PROP, pwd_symlink))

        self.doBuild(pwd_symlink, pwd_symlink)

        src_path = self.getBuildArtifact(_SRC_FILE)

        # /proc/self/cwd points to a realpath form of current directory.

        src_path = os.path.realpath(src_path)
@@ -53,8 +47,7 @@ class CompDirSymLinkTestCase(TestBase): 
    @skipIf(hostoslist=["windows"])

    def test_symlink_paths_unset(self):

        pwd_symlink = self.create_src_symlink()

        self.doBuild(pwd_symlink)

        self.runCmd('settings clear ' + _COMP_DIR_SYM_LINK_PROP)

        self.doBuild(pwd_symlink, "")

        src_path = self.getBuildArtifact(_SRC_FILE)

        self.assertRaises(

            AssertionError,
@@ -71,8 +64,12 @@ class CompDirSymLinkTestCase(TestBase): 
        self.addTearDownHook(lambda: os.remove(pwd_symlink))

        return pwd_symlink



    def doBuild(self, pwd_symlink):

    def doBuild(self, pwd_symlink, setting_value):

        self.build(None, None, {'PWD': pwd_symlink})



        self.runCmd(

            "settings set %s '%s'" %

            (_COMP_DIR_SYM_LINK_PROP, setting_value))



        exe = self.getBuildArtifact(_EXE_NAME)

        self.runCmd('file ' + exe, CURRENT_EXECUTABLE_SET)

lldb/source/Core/CoreProperties.td

+4 −0
Original line number Diff line number Diff line
@@ -9,6 +9,10 @@ let Definition = "modulelist" in { 
    Global,

    DefaultStringValue<"">,

    Desc<"The path to the clang modules cache directory (-fmodules-cache-path).">;

  def SymLinkPaths: Property<"debug-info-symlink-paths", "FileSpecList">,

    Global,

    DefaultStringValue<"">,

    Desc<"Debug info path which should be resolved while parsing, relative to the host filesystem.">;

}



let Definition = "debugger" in {

lldb/source/Core/ModuleList.cpp

+25 −0
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ 
#include "lldb/Core/ModuleSpec.h"

#include "lldb/Host/FileSystem.h"

#include "lldb/Interpreter/OptionValueFileSpec.h"

#include "lldb/Interpreter/OptionValueFileSpecList.h"

#include "lldb/Interpreter/OptionValueProperties.h"

#include "lldb/Interpreter/Property.h"

#include "lldb/Symbol/LocateSymbolFile.h"
@@ -77,6 +78,8 @@ ModuleListProperties::ModuleListProperties() { 
  m_collection_sp =

      std::make_shared<OptionValueProperties>(ConstString("symbols"));

  m_collection_sp->Initialize(g_modulelist_properties);

  m_collection_sp->SetValueChangedCallback(ePropertySymLinkPaths,

                                           [this] { UpdateSymlinkMappings(); });



  llvm::SmallString<128> path;

  clang::driver::Driver::getDefaultModuleCachePath(path);
@@ -106,6 +109,28 @@ bool ModuleListProperties::SetClangModulesCachePath(llvm::StringRef path) { 
      nullptr, ePropertyClangModulesCachePath, path);

}



void ModuleListProperties::UpdateSymlinkMappings() {

  FileSpecList list = m_collection_sp

                          ->GetPropertyAtIndexAsOptionValueFileSpecList(

                              nullptr, false, ePropertySymLinkPaths)

                          ->GetCurrentValue();

  llvm::sys::ScopedWriter lock(m_symlink_paths_mutex);

  const bool notify = false;

  m_symlink_paths.Clear(notify);

  for (FileSpec symlink : list) {

    FileSpec resolved;

    Status status = FileSystem::Instance().Readlink(symlink, resolved);

    if (status.Success())

      m_symlink_paths.Append(ConstString(symlink.GetPath()),

                             ConstString(resolved.GetPath()), notify);

  }

}



PathMappingList ModuleListProperties::GetSymlinkMappings() const {

  llvm::sys::ScopedReader lock(m_symlink_paths_mutex);

  return m_symlink_paths;

}



ModuleList::ModuleList()

    : m_modules(), m_modules_mutex(), m_notifier(nullptr) {}