Refresh android relocation packer from AOSP bionic.

Imports:
  Fix unit tests, and extend for other architectures
    https://android-review.googlesource.com/#/c/151901/

  Do not adjust PT_GNU_STACK segment
    https://android-review.googlesource.com/#/c/149300/

  Adjust DT_MIPS_RLD_MAP2 value
    https://android-review.googlesource.com/#/c/148822/

  Reduce p_align for program header to page size.
    https://android-review.googlesource.com/#/c/148492/

  Exit normally when relocations are already packed.
    https://android-review.googlesource.com/#/c/148175/

NOPRESUBMIT=true
BUG=385553

Review URL: https://codereview.chromium.org/1164453002

Cr-Commit-Position: refs/heads/master@{#331808}

16 files changed, 163 insertions, 20 deletions

diff --git a/third_party/android_platform/README.chromium b/third_party/android_platform/README.chromium
index 1dea3b60..192b9d6 100644
--- a/third_party/android_platform/README.chromium
+++ b/third_party/android_platform/README.chromium
@@ -40,7 +40,13 @@ Android relocation packing tool details:
     Create a nativehelper/ScopedFd.h to satisfy inclusion from main.cc
     Create gyp build
     Create gn build (currently packer only; no unit tests)
-    Apply https://android-review.googlesource.com/#/c/143878/
-    Apply https://android-review.googlesource.com/#/c/147620/
-          https://android-review.googlesource.com/#/c/147745/
-          https://android-review.googlesource.com/#/c/148073/
+    List of bionic changes currently included:
+      Refresh: https://android-review.googlesource.com/#/c/143878/
+      Refresh: https://android-review.googlesource.com/#/c/147620/
+               https://android-review.googlesource.com/#/c/147745/
+               https://android-review.googlesource.com/#/c/148073/
+      Refresh: https://android-review.googlesource.com/#/c/151901/
+               https://android-review.googlesource.com/#/c/149300/
+               https://android-review.googlesource.com/#/c/148822/
+               https://android-review.googlesource.com/#/c/148492/
+               https://android-review.googlesource.com/#/c/148175/
diff --git a/third_party/android_platform/bionic/tools/relocation_packer/Android.mk b/third_party/android_platform/bionic/tools/relocation_packer/Android.mk
index 99a39c0..94c946c 100644
--- a/third_party/android_platform/bionic/tools/relocation_packer/Android.mk
+++ b/third_party/android_platform/bionic/tools/relocation_packer/Android.mk
@@ -26,7 +26,6 @@ LOCAL_SRC_FILES := \
   src/debug.cc \
   src/delta_encoder.cc \
   src/elf_file.cc \
-  src/leb128.cc \
   src/packer.cc \
   src/sleb128.cc \
 
@@ -46,6 +45,9 @@ LOCAL_CPP_EXTENSION := .cc
 
 LOCAL_SRC_FILES := src/main.cc
 LOCAL_STATIC_LIBRARIES := lib_relocation_packer libelf
+
+# Statically linking libc++ to make it work from prebuilts
+LOCAL_CXX_STL := libc++_static
 LOCAL_C_INCLUDES := external/elfutils/src/libelf libnativehelper/include
 
 LOCAL_MODULE := relocation_packer
@@ -64,7 +66,6 @@ LOCAL_SRC_FILES := \
   src/debug_unittest.cc \
   src/delta_encoder_unittest.cc \
   src/elf_file_unittest.cc \
-  src/leb128_unittest.cc \
   src/sleb128_unittest.cc \
   src/packer_unittest.cc \
 
@@ -94,3 +95,9 @@ $(eval $(call copy-test-library,elf_file_unittest_relocs_arm32.so))
 $(eval $(call copy-test-library,elf_file_unittest_relocs_arm32_packed.so))
 $(eval $(call copy-test-library,elf_file_unittest_relocs_arm64.so))
 $(eval $(call copy-test-library,elf_file_unittest_relocs_arm64_packed.so))
+$(eval $(call copy-test-library,elf_file_unittest_relocs_ia32.so))
+$(eval $(call copy-test-library,elf_file_unittest_relocs_ia32_packed.so))
+$(eval $(call copy-test-library,elf_file_unittest_relocs_x64.so))
+$(eval $(call copy-test-library,elf_file_unittest_relocs_x64_packed.so))
+$(eval $(call copy-test-library,elf_file_unittest_relocs_mips32.so))
+$(eval $(call copy-test-library,elf_file_unittest_relocs_mips32_packed.so))
diff --git a/third_party/android_platform/bionic/tools/relocation_packer/src/elf_file.cc b/third_party/android_platform/bionic/tools/relocation_packer/src/elf_file.cc
index fb74233..4004239 100644
--- a/third_party/android_platform/bionic/tools/relocation_packer/src/elf_file.cc
+++ b/third_party/android_platform/bionic/tools/relocation_packer/src/elf_file.cc
@@ -37,11 +37,13 @@ static constexpr int32_t DT_ANDROID_RELASZ = DT_LOOS + 5;
 static constexpr uint32_t SHT_ANDROID_REL = SHT_LOOS + 1;
 static constexpr uint32_t SHT_ANDROID_RELA = SHT_LOOS + 2;
 
+static const size_t kPageSize = 4096;
+
 // Alignment to preserve, in bytes.  This must be at least as large as the
 // largest d_align and sh_addralign values found in the loaded file.
 // Out of caution for RELRO page alignment, we preserve to a complete target
 // page.  See http://www.airs.com/blog/archives/189.
-static constexpr size_t kPreserveAlignment = 4096;
+static const size_t kPreserveAlignment = kPageSize;
 
 // Get section data.  Checks that the section has exactly one data entry,
 // so that the section size and the data size are the same.  True in
@@ -300,16 +302,85 @@ static void AdjustSectionHeadersForHole(Elf* elf,
   }
 }
 
-// Helper for ResizeSection().  Adjust the offsets of any program headers
-// that have offsets currently beyond the hole start.
+// Helpers for ResizeSection().  On packing, reduce p_align for LOAD segments
+// to 4kb if larger.  On unpacking, restore p_align for LOAD segments if
+// packing reduced it to 4kb.  Return true if p_align was changed.
+template <typename ELF>
+static bool ClampLoadSegmentAlignment(typename ELF::Phdr* program_header) {
+  CHECK(program_header->p_type == PT_LOAD);
+
+  // If large, reduce p_align for a LOAD segment to page size on packing.
+  if (program_header->p_align > kPageSize) {
+    program_header->p_align = kPageSize;
+    return true;
+  }
+  return false;
+}
+
 template <typename ELF>
-static void AdjustProgramHeaderOffsets(typename ELF::Phdr* program_headers,
+static bool RestoreLoadSegmentAlignment(typename ELF::Phdr* program_headers,
+                                        size_t count,
+                                        typename ELF::Phdr* program_header) {
+  CHECK(program_header->p_type == PT_LOAD);
+
+  // If p_align was reduced on packing, restore it to its previous value
+  // on unpacking.  We do this by searching for a different LOAD segment
+  // and setting p_align to that of the other LOAD segment found.
+  //
+  // Relies on the following observations:
+  //   - a packable ELF executable has more than one LOAD segment;
+  //   - before packing all LOAD segments have the same p_align;
+  //   - on packing we reduce only one LOAD segment's p_align.
+  if (program_header->p_align == kPageSize) {
+    for (size_t i = 0; i < count; ++i) {
+      typename ELF::Phdr* other_header = &program_headers[i];
+      if (other_header->p_type == PT_LOAD && other_header != program_header) {
+        program_header->p_align = other_header->p_align;
+        return true;
+      }
+    }
+    LOG(WARNING) << "Cannot find a LOAD segment from which to restore p_align";
+  }
+  return false;
+}
+
+template <typename ELF>
+static bool AdjustLoadSegmentAlignment(typename ELF::Phdr* program_headers,
                                        size_t count,
-                                       typename ELF::Off hole_start,
+                                       typename ELF::Phdr* program_header,
                                        ssize_t hole_size) {
+  CHECK(program_header->p_type == PT_LOAD);
+
+  bool status = false;
+  if (hole_size < 0) {
+    status = ClampLoadSegmentAlignment<ELF>(program_header);
+  } else if (hole_size > 0) {
+    status = RestoreLoadSegmentAlignment<ELF>(program_headers,
+                                              count,
+                                              program_header);
+  }
+  return status;
+}
+
+// Helper for ResizeSection().  Adjust the offsets of any program headers
+// that have offsets currently beyond the hole start, and adjust the
+// virtual and physical addrs (and perhaps alignment) of the others.
+template <typename ELF>
+static void AdjustProgramHeaderFields(typename ELF::Phdr* program_headers,
+                                      size_t count,
+                                      typename ELF::Off hole_start,
+                                      ssize_t hole_size) {
+  int alignment_changes = 0;
   for (size_t i = 0; i < count; ++i) {
     typename ELF::Phdr* program_header = &program_headers[i];
 
+    // Do not adjust PT_GNU_STACK - it confuses gdb and results
+    // in incorrect unwinding if the executable is stripped after
+    // packing.
+    if (program_header->p_type == PT_GNU_STACK) {
+      continue;
+    }
+
     if (program_header->p_offset > hole_start) {
       // The hole start is past this segment, so adjust offset.
       program_header->p_offset += hole_size;
@@ -318,9 +389,24 @@ static void AdjustProgramHeaderOffsets(typename ELF::Phdr* program_headers,
     } else {
       program_header->p_vaddr -= hole_size;
       program_header->p_paddr -= hole_size;
+
+      // If packing, clamp LOAD segment alignment to 4kb to prevent strip
+      // from adjusting it unnecessarily if run on a packed file.  If
+      // unpacking, attempt to restore a reduced alignment to its previous
+      // value.  Ensure that we do this on at most one LOAD segment.
+      if (program_header->p_type == PT_LOAD) {
+        alignment_changes += AdjustLoadSegmentAlignment<ELF>(program_headers,
+                                                             count,
+                                                             program_header,
+                                                             hole_size);
+        LOG_IF(FATAL, alignment_changes > 1)
+            << "Changed p_align on more than one LOAD segment";
+      }
+
       VLOG(1) << "phdr[" << i
               << "] p_vaddr adjusted to "<< program_header->p_vaddr
-              << "; p_paddr adjusted to "<< program_header->p_paddr;
+              << "; p_paddr adjusted to "<< program_header->p_paddr
+              << "; p_align adjusted to "<< program_header->p_align;
     }
   }
 }
@@ -370,10 +456,10 @@ static void RewriteProgramHeadersForHole(Elf* elf,
   target_load_header->p_memsz += hole_size;
 
   // Adjust the offsets and p_vaddrs
-  AdjustProgramHeaderOffsets<ELF>(elf_program_header,
-                                  program_header_count,
-                                  hole_start,
-                                  hole_size);
+  AdjustProgramHeaderFields<ELF>(elf_program_header,
+                                 program_header_count,
+                                 hole_start,
+                                 hole_size);
 }
 
 // Helper for ResizeSection().  Locate and return the dynamic section.
@@ -466,6 +552,16 @@ void ElfFile<ELF>::AdjustDynamicSectionForHole(Elf_Scn* dynamic_section,
               << " d_val adjusted to " << dynamic->d_un.d_val;
     }
 
+    // Special case: DT_MIPS_RLD_MAP2 stores the difference between dynamic
+    // entry address and the address of the _r_debug (used by GDB)
+    // since the dynamic section and target address are on the
+    // different sides of the hole it needs to be adjusted accordingly
+    if (tag == DT_MIPS_RLD_MAP2) {
+      dynamic->d_un.d_val += hole_size;
+      VLOG(1) << "dynamic[" << i << "] " << dynamic->d_tag
+              << " d_val adjusted to " << dynamic->d_un.d_val;
+    }
+
     // Ignore DT_RELCOUNT and DT_RELACOUNT: (1) nobody uses them and
     // technically (2) the relative relocation count is not changed.
 
@@ -618,8 +714,8 @@ bool ElfFile<ELF>::PackTypedRelocations(std::vector<typename ELF::Rela>* relocat
   typedef typename ELF::Rela Rela;
 
   if (has_android_relocations_) {
-    LOG(ERROR) << "Relocation table is already packed";
-    return false;
+    LOG(INFO) << "Relocation table is already packed";
+    return true;
   }
 
   // If no relocations then we have nothing packable.  Perhaps
diff --git a/third_party/android_platform/bionic/tools/relocation_packer/src/elf_file_unittest.cc b/third_party/android_platform/bionic/tools/relocation_packer/src/elf_file_unittest.cc
index 5271eef..d5c8918 100644
--- a/third_party/android_platform/bionic/tools/relocation_packer/src/elf_file_unittest.cc
+++ b/third_party/android_platform/bionic/tools/relocation_packer/src/elf_file_unittest.cc
@@ -103,8 +103,8 @@ template <typename ELF>
 static void ProcessUnpack(FILE* relocs_so, FILE* packed_relocs_so) {
   relocation_packer::ElfFile<ELF> elf_file(fileno(packed_relocs_so));
 
-  // Ensure packing fails (already packed).
-  EXPECT_FALSE(elf_file.PackRelocations());
+  // Ensure packing already packed elf-file does not fail the build.
+  EXPECT_TRUE(elf_file.PackRelocations());
 
   // Unpack golden relocations, and check files are now identical.
   EXPECT_TRUE(elf_file.UnpackRelocations());
@@ -183,6 +183,18 @@ TEST(ElfFile, PackRelocationsArm64) {
   RunPackRelocationsTestFor("arm64");
 }
 
+TEST(ElfFile, PackRelocationsMips32) {
+  RunPackRelocationsTestFor("mips32");
+}
+
+TEST(ElfFile, PackRelocationsIa32) {
+  RunPackRelocationsTestFor("ia32");
+}
+
+TEST(ElfFile, PackRelocationsX64) {
+  RunPackRelocationsTestFor("x64");
+}
+
 TEST(ElfFile, UnpackRelocationsArm32) {
   RunUnpackRelocationsTestFor("arm32");
 }
@@ -191,4 +203,16 @@ TEST(ElfFile, UnpackRelocationsArm64) {
   RunUnpackRelocationsTestFor("arm64");
 }
 
+TEST(ElfFile, UnpackRelocationsMips32) {
+  RunUnpackRelocationsTestFor("mips32");
+}
+
+TEST(ElfFile, UnpackRelocationsIa32) {
+  RunUnpackRelocationsTestFor("ia32");
+}
+
+TEST(ElfFile, UnpackRelocationsX64) {
+  RunUnpackRelocationsTestFor("x64");
+}
+
 }  // namespace relocation_packer
diff --git a/third_party/android_platform/bionic/tools/relocation_packer/src/elf_traits.h b/third_party/android_platform/bionic/tools/relocation_packer/src/elf_traits.h
index 41b06c8..1c938fa 100644
--- a/third_party/android_platform/bionic/tools/relocation_packer/src/elf_traits.h
+++ b/third_party/android_platform/bionic/tools/relocation_packer/src/elf_traits.h
@@ -10,6 +10,10 @@
 #include "elf.h"
 #include "libelf.h"
 
+#if !defined(DT_MIPS_RLD_MAP2)
+#define DT_MIPS_RLD_MAP2 0x70000035
+#endif
+
 // ELF is a traits structure used to provide convenient aliases for
 // 32/64 bit Elf types and functions, depending on the target file.
 
diff --git a/third_party/android_platform/bionic/tools/relocation_packer/test_data/elf_file_unittest_relocs_arm32.so b/third_party/android_platform/bionic/tools/relocation_packer/test_data/elf_file_unittest_relocs_arm32.so
index 6ce6d0c..5e339ae 100755
--- a/third_party/android_platform/bionic/tools/relocation_packer/test_data/elf_file_unittest_relocs_arm32.so
+++ b/third_party/android_platform/bionic/tools/relocation_packer/test_data/elf_file_unittest_relocs_arm32.so
diff --git a/third_party/android_platform/bionic/tools/relocation_packer/test_data/elf_file_unittest_relocs_arm32_packed.so b/third_party/android_platform/bionic/tools/relocation_packer/test_data/elf_file_unittest_relocs_arm32_packed.so
index 6ac2eef..253dd97 100755
--- a/third_party/android_platform/bionic/tools/relocation_packer/test_data/elf_file_unittest_relocs_arm32_packed.so
+++ b/third_party/android_platform/bionic/tools/relocation_packer/test_data/elf_file_unittest_relocs_arm32_packed.so
diff --git a/third_party/android_platform/bionic/tools/relocation_packer/test_data/elf_file_unittest_relocs_arm64.so b/third_party/android_platform/bionic/tools/relocation_packer/test_data/elf_file_unittest_relocs_arm64.so
index 945b450..d3d0194 100755
--- a/third_party/android_platform/bionic/tools/relocation_packer/test_data/elf_file_unittest_relocs_arm64.so
+++ b/third_party/android_platform/bionic/tools/relocation_packer/test_data/elf_file_unittest_relocs_arm64.so
diff --git a/third_party/android_platform/bionic/tools/relocation_packer/test_data/elf_file_unittest_relocs_arm64_packed.so b/third_party/android_platform/bionic/tools/relocation_packer/test_data/elf_file_unittest_relocs_arm64_packed.so
index a2b0039..269b975 100755
--- a/third_party/android_platform/bionic/tools/relocation_packer/test_data/elf_file_unittest_relocs_arm64_packed.so
+++ b/third_party/android_platform/bionic/tools/relocation_packer/test_data/elf_file_unittest_relocs_arm64_packed.so
diff --git a/third_party/android_platform/bionic/tools/relocation_packer/test_data/elf_file_unittest_relocs_ia32.so b/third_party/android_platform/bionic/tools/relocation_packer/test_data/elf_file_unittest_relocs_ia32.so
new file mode 100644
index 0000000..42db62c
--- /dev/null
+++ b/third_party/android_platform/bionic/tools/relocation_packer/test_data/elf_file_unittest_relocs_ia32.so
diff --git a/third_party/android_platform/bionic/tools/relocation_packer/test_data/elf_file_unittest_relocs_ia32_packed.so b/third_party/android_platform/bionic/tools/relocation_packer/test_data/elf_file_unittest_relocs_ia32_packed.so
new file mode 100644
index 0000000..27817cc
--- /dev/null
+++ b/third_party/android_platform/bionic/tools/relocation_packer/test_data/elf_file_unittest_relocs_ia32_packed.so
diff --git a/third_party/android_platform/bionic/tools/relocation_packer/test_data/elf_file_unittest_relocs_mips32.so b/third_party/android_platform/bionic/tools/relocation_packer/test_data/elf_file_unittest_relocs_mips32.so
new file mode 100644
index 0000000..6da324b
--- /dev/null
+++ b/third_party/android_platform/bionic/tools/relocation_packer/test_data/elf_file_unittest_relocs_mips32.so
diff --git a/third_party/android_platform/bionic/tools/relocation_packer/test_data/elf_file_unittest_relocs_mips32_packed.so b/third_party/android_platform/bionic/tools/relocation_packer/test_data/elf_file_unittest_relocs_mips32_packed.so
new file mode 100644
index 0000000..b11ca48
--- /dev/null
+++ b/third_party/android_platform/bionic/tools/relocation_packer/test_data/elf_file_unittest_relocs_mips32_packed.so
diff --git a/third_party/android_platform/bionic/tools/relocation_packer/test_data/elf_file_unittest_relocs_x64.so b/third_party/android_platform/bionic/tools/relocation_packer/test_data/elf_file_unittest_relocs_x64.so
new file mode 100644
index 0000000..6cb689e
--- /dev/null
+++ b/third_party/android_platform/bionic/tools/relocation_packer/test_data/elf_file_unittest_relocs_x64.so
diff --git a/third_party/android_platform/bionic/tools/relocation_packer/test_data/elf_file_unittest_relocs_x64_packed.so b/third_party/android_platform/bionic/tools/relocation_packer/test_data/elf_file_unittest_relocs_x64_packed.so
new file mode 100644
index 0000000..60b9ad1
--- /dev/null
+++ b/third_party/android_platform/bionic/tools/relocation_packer/test_data/elf_file_unittest_relocs_x64_packed.so
diff --git a/third_party/android_platform/relocation_packer.gyp b/third_party/android_platform/relocation_packer.gyp
index a41253f..cb09841 100644
--- a/third_party/android_platform/relocation_packer.gyp
+++ b/third_party/android_platform/relocation_packer.gyp
@@ -73,6 +73,12 @@
             'bionic/tools/relocation_packer/test_data/elf_file_unittest_relocs_arm32_packed.so',
             'bionic/tools/relocation_packer/test_data/elf_file_unittest_relocs_arm64.so',
             'bionic/tools/relocation_packer/test_data/elf_file_unittest_relocs_arm64_packed.so',
+            'bionic/tools/relocation_packer/test_data/elf_file_unittest_relocs_ia32.so',
+            'bionic/tools/relocation_packer/test_data/elf_file_unittest_relocs_ia32_packed.so',
+            'bionic/tools/relocation_packer/test_data/elf_file_unittest_relocs_x64.so',
+            'bionic/tools/relocation_packer/test_data/elf_file_unittest_relocs_x64_packed.so',
+            'bionic/tools/relocation_packer/test_data/elf_file_unittest_relocs_mips32.so',
+            'bionic/tools/relocation_packer/test_data/elf_file_unittest_relocs_mips32_packed.so',
           ],
         },
       ],