Add support to read aux vector values

Summary:
This is the second patch to improve module loading in a series that started here (where I explain the motivation and solution): https://reviews.llvm.org/D62499

I need to read the aux vector to know where the r_debug map with the loaded libraries are.
The AuxVector class was made generic so it could be reused between the POSIX-DYLD plugin and NativeProcess*. The class itself ended up in the ProcessUtility plugin.

Reviewers: clayborg, xiaobai, labath, JDevlieghere

Reviewed By: clayborg, labath, JDevlieghere

Subscribers: emaste, JDevlieghere, mgorny, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D62500

llvm-svn: 363098

5 files changed, 14 insertions, 264 deletions

diff --git a/lldb/source/Plugins/DynamicLoader/POSIX-DYLD/AuxVector.cpp b/lldb/source/Plugins/DynamicLoader/POSIX-DYLD/AuxVector.cpp
deleted file mode 100644
index 71d42c8fd99..00000000000
--- a/lldb/source/Plugins/DynamicLoader/POSIX-DYLD/AuxVector.cpp
+++ /dev/null
@@ -1,141 +0,0 @@
-//===-- AuxVector.cpp -------------------------------------------*- C++ -*-===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-
-#include "AuxVector.h"
-#include "lldb/Target/Process.h"
-#include "lldb/Utility/DataBufferHeap.h"
-#include "lldb/Utility/DataExtractor.h"
-#include "lldb/Utility/Log.h"
-
-using namespace lldb;
-using namespace lldb_private;
-
-static bool GetMaxU64(DataExtractor &data, lldb::offset_t *offset_ptr,
-                      uint64_t *value, unsigned int byte_size) {
-  lldb::offset_t saved_offset = *offset_ptr;
-  *value = data.GetMaxU64(offset_ptr, byte_size);
-  return *offset_ptr != saved_offset;
-}
-
-static bool ParseAuxvEntry(DataExtractor &data, AuxVector::Entry &entry,
-                           lldb::offset_t *offset_ptr, unsigned int byte_size) {
-  if (!GetMaxU64(data, offset_ptr, &entry.type, byte_size))
-    return false;
-
-  if (!GetMaxU64(data, offset_ptr, &entry.value, byte_size))
-    return false;
-
-  return true;
-}
-
-DataBufferSP AuxVector::GetAuxvData() {
-  if (m_process)
-    return m_process->GetAuxvData();
-  else
-    return DataBufferSP();
-}
-
-void AuxVector::ParseAuxv(DataExtractor &data) {
-  const unsigned int byte_size = m_process->GetAddressByteSize();
-  lldb::offset_t offset = 0;
-
-  for (;;) {
-    Entry entry;
-
-    if (!ParseAuxvEntry(data, entry, &offset, byte_size))
-      break;
-
-    if (entry.type == AUXV_AT_NULL)
-      break;
-
-    if (entry.type == AUXV_AT_IGNORE)
-      continue;
-
-    m_auxv.push_back(entry);
-  }
-}
-
-AuxVector::AuxVector(Process *process) : m_process(process) {
-  DataExtractor data;
-  Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
-
-  data.SetData(GetAuxvData());
-  data.SetByteOrder(m_process->GetByteOrder());
-  data.SetAddressByteSize(m_process->GetAddressByteSize());
-
-  ParseAuxv(data);
-
-  if (log)
-    DumpToLog(log);
-}
-
-AuxVector::iterator AuxVector::FindEntry(EntryType type) const {
-  for (iterator I = begin(); I != end(); ++I) {
-    if (I->type == static_cast<uint64_t>(type))
-      return I;
-  }
-
-  return end();
-}
-
-void AuxVector::DumpToLog(Log *log) const {
-  if (!log)
-    return;
-
-  log->PutCString("AuxVector: ");
-  for (iterator I = begin(); I != end(); ++I) {
-    log->Printf("   %s [%" PRIu64 "]: %" PRIx64, GetEntryName(*I), I->type,
-                I->value);
-  }
-}
-
-const char *AuxVector::GetEntryName(EntryType type) {
-  const char *name = "AT_???";
-
-#define ENTRY_NAME(_type) \
-  _type:                  \
-  name = &#_type[5]
-  switch (type) {
-    case ENTRY_NAME(AUXV_AT_NULL);           break;
-    case ENTRY_NAME(AUXV_AT_IGNORE);         break;
-    case ENTRY_NAME(AUXV_AT_EXECFD);         break;
-    case ENTRY_NAME(AUXV_AT_PHDR);           break;
-    case ENTRY_NAME(AUXV_AT_PHENT);          break;
-    case ENTRY_NAME(AUXV_AT_PHNUM);          break;
-    case ENTRY_NAME(AUXV_AT_PAGESZ);         break;
-    case ENTRY_NAME(AUXV_AT_BASE);           break;
-    case ENTRY_NAME(AUXV_AT_FLAGS);          break;
-    case ENTRY_NAME(AUXV_AT_ENTRY);          break;
-    case ENTRY_NAME(AUXV_AT_NOTELF);         break;
-    case ENTRY_NAME(AUXV_AT_UID);            break;
-    case ENTRY_NAME(AUXV_AT_EUID);           break;
-    case ENTRY_NAME(AUXV_AT_GID);            break;
-    case ENTRY_NAME(AUXV_AT_EGID);           break;
-    case ENTRY_NAME(AUXV_AT_CLKTCK);         break;
-    case ENTRY_NAME(AUXV_AT_PLATFORM);       break;
-    case ENTRY_NAME(AUXV_AT_HWCAP);          break;
-    case ENTRY_NAME(AUXV_AT_FPUCW);          break;
-    case ENTRY_NAME(AUXV_AT_DCACHEBSIZE);    break;
-    case ENTRY_NAME(AUXV_AT_ICACHEBSIZE);    break;
-    case ENTRY_NAME(AUXV_AT_UCACHEBSIZE);    break;
-    case ENTRY_NAME(AUXV_AT_IGNOREPPC);      break;
-    case ENTRY_NAME(AUXV_AT_SECURE);         break;
-    case ENTRY_NAME(AUXV_AT_BASE_PLATFORM);  break;
-    case ENTRY_NAME(AUXV_AT_RANDOM);         break;
-    case ENTRY_NAME(AUXV_AT_EXECFN);         break;
-    case ENTRY_NAME(AUXV_AT_SYSINFO);        break;
-    case ENTRY_NAME(AUXV_AT_SYSINFO_EHDR);   break;
-    case ENTRY_NAME(AUXV_AT_L1I_CACHESHAPE); break;
-    case ENTRY_NAME(AUXV_AT_L1D_CACHESHAPE); break;
-    case ENTRY_NAME(AUXV_AT_L2_CACHESHAPE);  break;
-    case ENTRY_NAME(AUXV_AT_L3_CACHESHAPE);  break;
-    }
-#undef ENTRY_NAME
-
-    return name;
-}
diff --git a/lldb/source/Plugins/DynamicLoader/POSIX-DYLD/AuxVector.h b/lldb/source/Plugins/DynamicLoader/POSIX-DYLD/AuxVector.h
deleted file mode 100644
index cf32d9cd30f..00000000000
--- a/lldb/source/Plugins/DynamicLoader/POSIX-DYLD/AuxVector.h
+++ /dev/null
@@ -1,108 +0,0 @@
-//===-- AuxVector.h ---------------------------------------------*- C++ -*-===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef liblldb_AuxVector_H_
-#define liblldb_AuxVector_H_
-
-#include <vector>
-
-#include "lldb/lldb-forward.h"
-
-namespace lldb_private {
-class DataExtractor;
-}
-
-/// \class AuxVector
-/// Represents a processes auxiliary vector.
-///
-/// When a process is loaded on Linux a vector of values is placed onto the
-/// stack communicating operating system specific information.  On
-/// construction this class locates and parses this information and provides a
-/// simple read-only interface to the entries found.
-class AuxVector {
-
-public:
-  AuxVector(lldb_private::Process *process);
-
-  struct Entry {
-    uint64_t type;
-    uint64_t value;
-
-    Entry() : type(0), value(0) {}
-  };
-
-  /// Constants describing the type of entry.
-  /// On Linux, running "LD_SHOW_AUXV=1 ./executable" will spew AUX
-  /// information. Added AUXV prefix to avoid potential conflicts with system-
-  /// defined macros
-  enum EntryType {
-    AUXV_AT_NULL = 0,            ///< End of auxv.
-    AUXV_AT_IGNORE = 1,          ///< Ignore entry.
-    AUXV_AT_EXECFD = 2,          ///< File descriptor of program.
-    AUXV_AT_PHDR = 3,            ///< Program headers.
-    AUXV_AT_PHENT = 4,           ///< Size of program header.
-    AUXV_AT_PHNUM = 5,           ///< Number of program headers.
-    AUXV_AT_PAGESZ = 6,          ///< Page size.
-    AUXV_AT_BASE = 7,            ///< Interpreter base address.
-    AUXV_AT_FLAGS = 8,           ///< Flags.
-    AUXV_AT_ENTRY = 9,           ///< Program entry point.
-    AUXV_AT_NOTELF = 10,         ///< Set if program is not an ELF.
-    AUXV_AT_UID = 11,            ///< UID.
-    AUXV_AT_EUID = 12,           ///< Effective UID.
-    AUXV_AT_GID = 13,            ///< GID.
-    AUXV_AT_EGID = 14,           ///< Effective GID.
-    AUXV_AT_CLKTCK = 17,         ///< Clock frequency (e.g. times(2)).
-    AUXV_AT_PLATFORM = 15,       ///< String identifying platform.
-    AUXV_AT_HWCAP = 16,          ///< Machine dependent hints about processor capabilities.
-    AUXV_AT_FPUCW = 18,          ///< Used FPU control word.
-    AUXV_AT_DCACHEBSIZE = 19,    ///< Data cache block size.
-    AUXV_AT_ICACHEBSIZE = 20,    ///< Instruction cache block size.
-    AUXV_AT_UCACHEBSIZE = 21,    ///< Unified cache block size.
-    AUXV_AT_IGNOREPPC = 22,      ///< Entry should be ignored.
-    AUXV_AT_SECURE = 23,         ///< Boolean, was exec setuid-like?
-    AUXV_AT_BASE_PLATFORM = 24,  ///< String identifying real platforms.
-    AUXV_AT_RANDOM = 25,         ///< Address of 16 random bytes.
-    AUXV_AT_EXECFN = 31,         ///< Filename of executable.
-    AUXV_AT_SYSINFO = 32,        ///< Pointer to the global system page used for system
-                                 ///calls and other nice things.
-    AUXV_AT_SYSINFO_EHDR = 33,
-    AUXV_AT_L1I_CACHESHAPE = 34, ///< Shapes of the caches.
-    AUXV_AT_L1D_CACHESHAPE = 35,
-    AUXV_AT_L2_CACHESHAPE = 36,
-    AUXV_AT_L3_CACHESHAPE = 37,
-  };
-
-private:
-  typedef std::vector<Entry> EntryVector;
-
-public:
-  typedef EntryVector::const_iterator iterator;
-
-  iterator begin() const { return m_auxv.begin(); }
-  iterator end() const { return m_auxv.end(); }
-
-  iterator FindEntry(EntryType type) const;
-
-  static const char *GetEntryName(const Entry &entry) {
-    return GetEntryName(static_cast<EntryType>(entry.type));
-  }
-
-  static const char *GetEntryName(EntryType type);
-
-  void DumpToLog(lldb_private::Log *log) const;
-
-private:
-  lldb_private::Process *m_process;
-  EntryVector m_auxv;
-
-  lldb::DataBufferSP GetAuxvData();
-
-  void ParseAuxv(lldb_private::DataExtractor &data);
-};
-
-#endif
diff --git a/lldb/source/Plugins/DynamicLoader/POSIX-DYLD/CMakeLists.txt b/lldb/source/Plugins/DynamicLoader/POSIX-DYLD/CMakeLists.txt
index 409ba92a0e1..c1e00b2dd44 100644
--- a/lldb/source/Plugins/DynamicLoader/POSIX-DYLD/CMakeLists.txt
+++ b/lldb/source/Plugins/DynamicLoader/POSIX-DYLD/CMakeLists.txt
@@ -1,5 +1,4 @@
 add_lldb_library(lldbPluginDynamicLoaderPosixDYLD PLUGIN
-  AuxVector.cpp
   DYLDRendezvous.cpp
   DynamicLoaderPOSIXDYLD.cpp
 
@@ -10,6 +9,7 @@ add_lldb_library(lldbPluginDynamicLoaderPosixDYLD PLUGIN
     lldbSymbol
     lldbTarget
     lldbPluginProcessElfCore
+    lldbPluginProcessUtility
   LINK_COMPONENTS
     Support
   )
diff --git a/lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DynamicLoaderPOSIXDYLD.cpp b/lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DynamicLoaderPOSIXDYLD.cpp
index 591a27f4492..b55660899d0 100644
--- a/lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DynamicLoaderPOSIXDYLD.cpp
+++ b/lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DynamicLoaderPOSIXDYLD.cpp
@@ -9,8 +9,6 @@
 // Main header include
 #include "DynamicLoaderPOSIXDYLD.h"
 
-#include "AuxVector.h"
-
 #include "lldb/Breakpoint/BreakpointLocation.h"
 #include "lldb/Core/Module.h"
 #include "lldb/Core/ModuleSpec.h"
@@ -90,8 +88,8 @@ void DynamicLoaderPOSIXDYLD::DidAttach() {
   if (log)
     log->Printf("DynamicLoaderPOSIXDYLD::%s() pid %" PRIu64, __FUNCTION__,
                 m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID);
+  m_auxv = llvm::make_unique<AuxVector>(m_process->GetAuxvData());
 
-  m_auxv.reset(new AuxVector(m_process));
   if (log)
     log->Printf("DynamicLoaderPOSIXDYLD::%s pid %" PRIu64 " reloaded auxv data",
                 __FUNCTION__,
@@ -182,7 +180,7 @@ void DynamicLoaderPOSIXDYLD::DidLaunch() {
   ModuleSP executable;
   addr_t load_offset;
 
-  m_auxv.reset(new AuxVector(m_process));
+  m_auxv = llvm::make_unique<AuxVector>(m_process->GetAuxvData());
 
   executable = GetTargetExecutable();
   load_offset = ComputeLoadOffset();
@@ -628,13 +626,13 @@ addr_t DynamicLoaderPOSIXDYLD::ComputeLoadOffset() {
 }
 
 void DynamicLoaderPOSIXDYLD::EvalSpecialModulesStatus() {
-  auto I = m_auxv->FindEntry(AuxVector::AUXV_AT_SYSINFO_EHDR);
-  if (I != m_auxv->end() && I->value != 0)
-    m_vdso_base = I->value;
+  if (llvm::Optional<uint64_t> vdso_base =
+          m_auxv->GetAuxValue(AuxVector::AUXV_AT_SYSINFO_EHDR))
+    m_vdso_base = *vdso_base;
 
-  I = m_auxv->FindEntry(AuxVector::AUXV_AT_BASE);
-  if (I != m_auxv->end() && I->value != 0)
-    m_interpreter_base = I->value;
+  if (llvm::Optional<uint64_t> interpreter_base =
+          m_auxv->GetAuxValue(AuxVector::AUXV_AT_BASE))
+    m_interpreter_base = *interpreter_base;
 }
 
 addr_t DynamicLoaderPOSIXDYLD::GetEntryPoint() {
@@ -644,12 +642,12 @@ addr_t DynamicLoaderPOSIXDYLD::GetEntryPoint() {
   if (m_auxv == nullptr)
     return LLDB_INVALID_ADDRESS;
 
-  AuxVector::iterator I = m_auxv->FindEntry(AuxVector::AUXV_AT_ENTRY);
-
-  if (I == m_auxv->end())
+  llvm::Optional<uint64_t> entry_point =
+      m_auxv->GetAuxValue(AuxVector::AUXV_AT_ENTRY);
+  if (!entry_point)
     return LLDB_INVALID_ADDRESS;
 
-  m_entry_point = static_cast<addr_t>(I->value);
+  m_entry_point = static_cast<addr_t>(*entry_point);
 
   const ArchSpec &arch = m_process->GetTarget().GetArchitecture();
 
diff --git a/lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DynamicLoaderPOSIXDYLD.h b/lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DynamicLoaderPOSIXDYLD.h
index d61f1563497..0630d1eb11d 100644
--- a/lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DynamicLoaderPOSIXDYLD.h
+++ b/lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DynamicLoaderPOSIXDYLD.h
@@ -13,6 +13,7 @@
 #include <memory>
 
 #include "DYLDRendezvous.h"
+#include "Plugins/Process/Utility/AuxVector.h"
 #include "lldb/Breakpoint/StoppointCallbackContext.h"
 #include "lldb/Core/ModuleList.h"
 #include "lldb/Target/DynamicLoader.h"