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Diffstat (limited to 'absl/debugging/symbolize_elf.inc')
-rw-r--r--absl/debugging/symbolize_elf.inc52
1 files changed, 33 insertions, 19 deletions
diff --git a/absl/debugging/symbolize_elf.inc b/absl/debugging/symbolize_elf.inc
index 0fee89f2..30638cb2 100644
--- a/absl/debugging/symbolize_elf.inc
+++ b/absl/debugging/symbolize_elf.inc
@@ -658,8 +658,10 @@ static bool ShouldPickFirstSymbol(const ElfW(Sym) & symbol1,
}
// Return true if an address is inside a section.
-static bool InSection(const void *address, const ElfW(Shdr) * section) {
- const char *start = reinterpret_cast<const char *>(section->sh_addr);
+static bool InSection(const void *address, ptrdiff_t relocation,
+ const ElfW(Shdr) * section) {
+ const char *start = reinterpret_cast<const char *>(
+ section->sh_addr + static_cast<ElfW(Addr)>(relocation));
size_t size = static_cast<size_t>(section->sh_size);
return start <= address && address < (start + size);
}
@@ -699,8 +701,8 @@ static ABSL_ATTRIBUTE_NOINLINE FindSymbolResult FindSymbol(
// starting address. However, we do not always want to use the real
// starting address because we sometimes want to symbolize a function
// pointer into the .opd section, e.g. FindSymbol(&foo,...).
- const bool pc_in_opd =
- kPlatformUsesOPDSections && opd != nullptr && InSection(pc, opd);
+ const bool pc_in_opd = kPlatformUsesOPDSections && opd != nullptr &&
+ InSection(pc, relocation, opd);
const bool deref_function_descriptor_pointer =
kPlatformUsesOPDSections && opd != nullptr && !pc_in_opd;
@@ -740,7 +742,7 @@ static ABSL_ATTRIBUTE_NOINLINE FindSymbolResult FindSymbol(
#endif
if (deref_function_descriptor_pointer &&
- InSection(original_start_address, opd)) {
+ InSection(original_start_address, /*relocation=*/0, opd)) {
// The opd section is mapped into memory. Just dereference
// start_address to get the first double word, which points to the
// function entry.
@@ -1336,7 +1338,7 @@ static bool MaybeInitializeObjFile(ObjFile *obj) {
const int phnum = obj->elf_header.e_phnum;
const int phentsize = obj->elf_header.e_phentsize;
auto phoff = static_cast<off_t>(obj->elf_header.e_phoff);
- size_t num_executable_load_segments = 0;
+ size_t num_interesting_load_segments = 0;
for (int j = 0; j < phnum; j++) {
ElfW(Phdr) phdr;
if (!ReadFromOffsetExact(obj->fd, &phdr, sizeof(phdr), phoff)) {
@@ -1345,23 +1347,35 @@ static bool MaybeInitializeObjFile(ObjFile *obj) {
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.
+
+#if defined(__powerpc__) && !(_CALL_ELF > 1)
+ // On the PowerPC ELF v1 ABI, function pointers actually point to function
+ // descriptors. These descriptors are stored in an .opd section, which is
+ // mapped read-only. We thus need to look at all readable segments, not
+ // just the executable ones.
+ constexpr int interesting = PF_R;
+#else
+ constexpr int interesting = PF_X | PF_R;
+#endif
+
+ if (phdr.p_type != PT_LOAD
+ || (phdr.p_flags & interesting) != interesting) {
+ // Not a LOAD segment, not executable code, and not a function
+ // descriptor.
continue;
}
- if (num_executable_load_segments < obj->phdr.size()) {
- memcpy(&obj->phdr[num_executable_load_segments++], &phdr, sizeof(phdr));
+ if (num_interesting_load_segments < obj->phdr.size()) {
+ memcpy(&obj->phdr[num_interesting_load_segments++], &phdr, sizeof(phdr));
} else {
ABSL_RAW_LOG(
- WARNING, "%s: too many executable LOAD segments: %zu >= %zu",
- obj->filename, num_executable_load_segments, obj->phdr.size());
+ WARNING, "%s: too many interesting LOAD segments: %zu >= %zu",
+ obj->filename, num_interesting_load_segments, obj->phdr.size());
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);
+ if (num_interesting_load_segments == 0) {
+ // This object has no interesting LOAD segments. That's unexpected.
+ ABSL_RAW_LOG(WARNING, "%s: no interesting LOAD segments", obj->filename);
return false;
}
}
@@ -1389,8 +1403,8 @@ const char *Symbolizer::GetUncachedSymbol(const void *pc) {
// X in the file will have a start address of [true relocation]+X.
relocation = static_cast<ptrdiff_t>(start_addr - obj->offset);
- // Note: some binaries have multiple "rx" LOAD segments. We must
- // find the right one.
+ // Note: some binaries have multiple LOAD segments that can contain
+ // function pointers. We must find the right one.
ElfW(Phdr) *phdr = nullptr;
for (size_t j = 0; j < obj->phdr.size(); j++) {
ElfW(Phdr) &p = obj->phdr[j];
@@ -1400,7 +1414,7 @@ const char *Symbolizer::GetUncachedSymbol(const void *pc) {
ABSL_RAW_CHECK(p.p_type == PT_NULL, "unexpected p_type");
break;
}
- if (pc < reinterpret_cast<void *>(start_addr + p.p_memsz)) {
+ if (pc < reinterpret_cast<void *>(start_addr + p.p_vaddr + p.p_memsz)) {
phdr = &p;
break;
}