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authorGravatar Abseil Team <absl-team@google.com>2020-07-07 08:27:11 -0700
committerGravatar Gennadiy Rozental <rogeeff@google.com>2020-07-07 11:37:48 -0400
commitbf655de09b67fd8b924814cbb369cb65ddd0bd24 (patch)
treefe73ac9c036d82843b99b3b364686f2eb57c0e24
parent38db52adb2eabc0969195b33b30763e0a1285ef9 (diff)
Export of internal Abseil changes
-- 13b7cb0eff8fda5127193e11dbe0b8655415b512 by Gennadiy Rozental <rogeeff@google.com>: Change the preprocessor guards to properly exclude tests which does not build on older version on libstdc++. Fixes #731 PiperOrigin-RevId: 319987618 -- ab2155855b4dd1259a3dd9f48fbb5e6e8c2ccd3f by Derek Mauro <dmauro@google.com>: Update clang-latest container to LLVM 052e1e0cfd9, Bazel 3.3.1, and CMake 3.17.3 PiperOrigin-RevId: 319835484 -- 7554283733c309649a05b7f1891b2593e50f07b7 by Abseil Team <absl-team@google.com>: Implement support for LOAD segments that don't start at p_vaddr==0. PiperOrigin-RevId: 319694669 GitOrigin-RevId: 13b7cb0eff8fda5127193e11dbe0b8655415b512 Change-Id: I220c2af4169cf8e4dad20cb372589ec7def0e018
-rw-r--r--absl/container/btree_test.cc9
-rw-r--r--absl/debugging/symbolize_elf.inc85
-rw-r--r--ci/linux_docker_containers.sh2
3 files changed, 82 insertions, 14 deletions
diff --git a/absl/container/btree_test.cc b/absl/container/btree_test.cc
index 1738d291..c5808074 100644
--- a/absl/container/btree_test.cc
+++ b/absl/container/btree_test.cc
@@ -2463,9 +2463,12 @@ TEST(Btree,
EXPECT_THAT(s2, ElementsAre(IsEmpty(), ElementsAre(IsNull())));
}
-// GCC 4.9 has a bug in the std::pair constructors that prevents explicit
-// conversions between pair types.
-#if defined(__clang__) || !defined(__GNUC__) || __GNUC__ >= 5
+// libstdc++ included with GCC 4.9 has a bug in the std::pair constructors that
+// prevents explicit conversions between pair types.
+// We only run this test for the libstdc++ from GCC 7 or newer because we can't
+// reliably check the libstdc++ version prior to that release.
+#if !defined(__GLIBCXX__) || \
+ (defined(_GLIBCXX_RELEASE) && _GLIBCXX_RELEASE >= 7)
TEST(Btree, MapRangeConstructorAndInsertSupportExplicitConversionComparable) {
const std::pair<absl::string_view, int> names[] = {{"n1", 1}, {"n2", 2}};
diff --git a/absl/debugging/symbolize_elf.inc b/absl/debugging/symbolize_elf.inc
index b7f8663c..2f97cc7e 100644
--- a/absl/debugging/symbolize_elf.inc
+++ b/absl/debugging/symbolize_elf.inc
@@ -57,6 +57,7 @@
#include <unistd.h>
#include <algorithm>
+#include <array>
#include <atomic>
#include <cerrno>
#include <cinttypes>
@@ -184,6 +185,7 @@ struct ObjFile {
fd(-1),
elf_type(-1) {
SafeMemZero(&elf_header, sizeof(elf_header));
+ SafeMemZero(&phdr[0], sizeof(phdr));
}
char *filename;
@@ -196,6 +198,10 @@ struct ObjFile {
int fd;
int elf_type;
ElfW(Ehdr) elf_header;
+
+ // PT_LOAD program header describing executable code.
+ // Normally we expect just one, but SWIFT binaries have two.
+ std::array<ElfW(Phdr), 2> phdr;
};
// Build 4-way associative cache for symbols. Within each cache line, symbols
@@ -1272,6 +1278,36 @@ static bool MaybeInitializeObjFile(ObjFile *obj) {
ABSL_RAW_LOG(WARNING, "%s: failed to read elf header", obj->filename);
return false;
}
+ const int phnum = obj->elf_header.e_phnum;
+ const int phentsize = obj->elf_header.e_phentsize;
+ size_t phoff = obj->elf_header.e_phoff;
+ int num_executable_load_segments = 0;
+ for (int j = 0; j < phnum; j++) {
+ ElfW(Phdr) phdr;
+ if (!ReadFromOffsetExact(obj->fd, &phdr, sizeof(phdr), phoff)) {
+ ABSL_RAW_LOG(WARNING, "%s: failed to read program header %d",
+ obj->filename, j);
+ return false;
+ }
+ phoff += phentsize;
+ constexpr int rx = PF_X | PF_R;
+ if (phdr.p_type != PT_LOAD || (phdr.p_flags & rx) != rx) {
+ // Not a LOAD segment, or not executable code.
+ continue;
+ }
+ if (num_executable_load_segments < obj->phdr.size()) {
+ memcpy(&obj->phdr[num_executable_load_segments++], &phdr, sizeof(phdr));
+ } else {
+ ABSL_RAW_LOG(WARNING, "%s: too many executable LOAD segments",
+ obj->filename);
+ break;
+ }
+ }
+ if (num_executable_load_segments == 0) {
+ // This object has no "r-x" LOAD segments. That's unexpected.
+ ABSL_RAW_LOG(WARNING, "%s: no executable LOAD segments", obj->filename);
+ return false;
+ }
}
return true;
}
@@ -1295,23 +1331,52 @@ const char *Symbolizer::GetSymbol(const void *const pc) {
int fd = -1;
if (obj != nullptr) {
if (MaybeInitializeObjFile(obj)) {
- if (obj->elf_type == ET_DYN &&
- reinterpret_cast<uint64_t>(obj->start_addr) >= obj->offset) {
+ const size_t start_addr = reinterpret_cast<size_t>(obj->start_addr);
+ if (obj->elf_type == ET_DYN && start_addr >= obj->offset) {
// This object was relocated.
//
// For obj->offset > 0, adjust the relocation since a mapping at offset
// X in the file will have a start address of [true relocation]+X.
- relocation = reinterpret_cast<ptrdiff_t>(obj->start_addr) - obj->offset;
+ relocation = start_addr - obj->offset;
+
+ // Note: some binaries have multiple "rx" LOAD segments. We must
+ // find the right one.
+ ElfW(Phdr) *phdr = nullptr;
+ for (int j = 0; j < obj->phdr.size(); j++) {
+ ElfW(Phdr) &p = obj->phdr[j];
+ if (p.p_type != PT_LOAD) {
+ // We only expect PT_LOADs. This must be PT_NULL that we didn't
+ // write over (i.e. we exhausted all interesting PT_LOADs).
+ ABSL_RAW_CHECK(p.p_type == PT_NULL, "unexpected p_type");
+ break;
+ }
+ if (pc < reinterpret_cast<void *>(start_addr + p.p_memsz)) {
+ phdr = &p;
+ break;
+ }
+ }
+ if (phdr == nullptr) {
+ // That's unexpected. Hope for the best.
+ ABSL_RAW_LOG(
+ WARNING,
+ "%s: unable to find LOAD segment for pc: %p, start_addr: %zx",
+ obj->filename, pc, start_addr);
+ } else {
+ // Adjust relocation in case phdr.p_vaddr != 0.
+ // This happens for binaries linked with `lld --rosegment`, and for
+ // binaries linked with BFD `ld -z separate-code`.
+ relocation -= phdr->p_vaddr - phdr->p_offset;
+ }
}
fd = obj->fd;
- }
- if (GetSymbolFromObjectFile(*obj, pc, relocation, symbol_buf_,
- sizeof(symbol_buf_), tmp_buf_,
- sizeof(tmp_buf_)) == SYMBOL_FOUND) {
- // Only try to demangle the symbol name if it fit into symbol_buf_.
- DemangleInplace(symbol_buf_, sizeof(symbol_buf_), tmp_buf_,
- sizeof(tmp_buf_));
+ if (GetSymbolFromObjectFile(*obj, pc, relocation, symbol_buf_,
+ sizeof(symbol_buf_), tmp_buf_,
+ sizeof(tmp_buf_)) == SYMBOL_FOUND) {
+ // Only try to demangle the symbol name if it fit into symbol_buf_.
+ DemangleInplace(symbol_buf_, sizeof(symbol_buf_), tmp_buf_,
+ sizeof(tmp_buf_));
+ }
}
} else {
#if ABSL_HAVE_VDSO_SUPPORT
diff --git a/ci/linux_docker_containers.sh b/ci/linux_docker_containers.sh
index 82a10ac6..b652071f 100644
--- a/ci/linux_docker_containers.sh
+++ b/ci/linux_docker_containers.sh
@@ -16,6 +16,6 @@
# Test scripts should source this file to get the identifiers.
readonly LINUX_ALPINE_CONTAINER="gcr.io/google.com/absl-177019/alpine:20191016"
-readonly LINUX_CLANG_LATEST_CONTAINER="gcr.io/google.com/absl-177019/linux_clang-latest:20200401"
+readonly LINUX_CLANG_LATEST_CONTAINER="gcr.io/google.com/absl-177019/linux_clang-latest:20200706"
readonly LINUX_GCC_LATEST_CONTAINER="gcr.io/google.com/absl-177019/linux_gcc-latest:20200319"
readonly LINUX_GCC_49_CONTAINER="gcr.io/google.com/absl-177019/linux_gcc-4.9:20191018"