Remove Memory::ReadField.
In almost all cases, it is faster to read the entire structure rather
than do multiple reads using ReadField. The only case where it would be
slower is if doing a remote unwind and ptrace is the only way to read. In
all other cases, it's a single system call. In the ptrace call, it will be
multiple calls. Given that it is unusual to be forced to use ptrace,
it's better to avoid it.
It also reduces the code complexity to do a single read, and avoids
issues where the code forgets to read the field it needs.
Test: Unit tests pass on host and target.
Change-Id: I7b3875b2c85d0d88115b1776e1be28521dc0b932
diff --git a/libunwindstack/ElfInterfaceArm.cpp b/libunwindstack/ElfInterfaceArm.cpp
index a3244e8..3dd5d54 100644
--- a/libunwindstack/ElfInterfaceArm.cpp
+++ b/libunwindstack/ElfInterfaceArm.cpp
@@ -87,23 +87,17 @@
#define PT_ARM_EXIDX 0x70000001
#endif
-bool ElfInterfaceArm::HandleType(uint64_t offset, uint32_t type) {
+void ElfInterfaceArm::HandleUnknownType(uint32_t type, uint64_t ph_offset, uint64_t ph_filesz) {
if (type != PT_ARM_EXIDX) {
- return false;
- }
-
- Elf32_Phdr phdr;
- if (!memory_->ReadFully(offset, &phdr, sizeof(phdr))) {
- return true;
+ return;
}
// The offset already takes into account the load bias.
- start_offset_ = phdr.p_offset;
+ start_offset_ = ph_offset;
// Always use filesz instead of memsz. In most cases they are the same,
// but some shared libraries wind up setting one correctly and not the other.
- total_entries_ = phdr.p_filesz / 8;
- return true;
+ total_entries_ = ph_filesz / 8;
}
bool ElfInterfaceArm::Step(uint64_t pc, Regs* regs, Memory* process_memory, bool* finished) {