Fix handling of load bias values.
It turns out that for the dwarf information, if a FDE indicates it's pc
relative, then pc has to be incremented by the load bias. If not, then
it should not be incremented.
Previously, the code always subtracted load bias values from pcs, and assumed
that all fdes were incremented by load bias values. The new code actually
reads the fdes and adjusted the pcs in the fde and in the eh frame hdr so
that load bias values are already handled properly.
In addition, add dumping of arm exidx values in unwind_reg_info. This allowed
verifying that the debug frame in those elf files was being handled properly.
Added a new unit test that only has a debug frame that has a non-zero load
bias and has fde entries that do not have pc relative encoding.
Fix a couple of other small bugs.
Bug: 109824792
Test: All libbacktrace/libunwindstack unit tests pass.
Test: Ran ART 137-cfi test and 004-ThreadStress.
Test: Verify that displaying the fde start and end pc actually match the
Test: real data for fde that have pc relative set, and that don't.
Test: Verified that the unwind information for arm exidx matches the
Test: debug frame data.
Change-Id: I707555286b5cb05df9f25489e8c5ede753cfe0fb
diff --git a/libunwindstack/DwarfSection.cpp b/libunwindstack/DwarfSection.cpp
index 65eec65..eb83949 100644
--- a/libunwindstack/DwarfSection.cpp
+++ b/libunwindstack/DwarfSection.cpp
@@ -420,6 +420,7 @@
last_error_.address = memory_.cur_offset();
return false;
}
+ memory_.set_pc_offset(pc_offset_);
if (!memory_.ReadEncodedValue<AddressType>(encoding, &cie->personality_handler)) {
last_error_.code = DWARF_ERROR_MEMORY_INVALID;
last_error_.address = memory_.cur_offset();
@@ -521,19 +522,19 @@
}
memory_.set_cur_offset(cur_offset);
- if (!memory_.ReadEncodedValue<AddressType>(cie->fde_address_encoding & 0xf, &fde->pc_start)) {
- last_error_.code = DWARF_ERROR_MEMORY_INVALID;
- last_error_.address = memory_.cur_offset();
- return false;
- }
+ // The load bias only applies to the start.
+ memory_.set_pc_offset(load_bias_);
+ bool valid = memory_.ReadEncodedValue<AddressType>(cie->fde_address_encoding, &fde->pc_start);
fde->pc_start = AdjustPcFromFde(fde->pc_start);
- if (!memory_.ReadEncodedValue<AddressType>(cie->fde_address_encoding & 0xf, &fde->pc_end)) {
+ memory_.set_pc_offset(0);
+ if (!valid || !memory_.ReadEncodedValue<AddressType>(cie->fde_address_encoding, &fde->pc_end)) {
last_error_.code = DWARF_ERROR_MEMORY_INVALID;
last_error_.address = memory_.cur_offset();
return false;
}
fde->pc_end += fde->pc_start;
+
if (cie->augmentation_string.size() > 0 && cie->augmentation_string[0] == 'z') {
// Augmentation Size
uint64_t aug_length;
@@ -544,6 +545,7 @@
}
uint64_t cur_offset = memory_.cur_offset();
+ memory_.set_pc_offset(pc_offset_);
if (!memory_.ReadEncodedValue<AddressType>(cie->lsda_encoding, &fde->lsda_address)) {
last_error_.code = DWARF_ERROR_MEMORY_INVALID;
last_error_.address = memory_.cur_offset();
@@ -582,17 +584,16 @@
}
template <typename AddressType>
-bool DwarfSectionImpl<AddressType>::Log(uint8_t indent, uint64_t pc, uint64_t load_bias,
- const DwarfFde* fde) {
+bool DwarfSectionImpl<AddressType>::Log(uint8_t indent, uint64_t pc, const DwarfFde* fde) {
DwarfCfa<AddressType> cfa(&memory_, fde);
// Always print the cie information.
const DwarfCie* cie = fde->cie;
- if (!cfa.Log(indent, pc, load_bias, cie->cfa_instructions_offset, cie->cfa_instructions_end)) {
+ if (!cfa.Log(indent, pc, cie->cfa_instructions_offset, cie->cfa_instructions_end)) {
last_error_ = cfa.last_error();
return false;
}
- if (!cfa.Log(indent, pc, load_bias, fde->cfa_instructions_offset, fde->cfa_instructions_end)) {
+ if (!cfa.Log(indent, pc, fde->cfa_instructions_offset, fde->cfa_instructions_end)) {
last_error_ = cfa.last_error();
return false;
}
@@ -600,15 +601,16 @@
}
template <typename AddressType>
-bool DwarfSectionImpl<AddressType>::Init(uint64_t offset, uint64_t size) {
+bool DwarfSectionImpl<AddressType>::Init(uint64_t offset, uint64_t size, uint64_t load_bias) {
+ load_bias_ = load_bias;
entries_offset_ = offset;
entries_end_ = offset + size;
memory_.clear_func_offset();
memory_.clear_text_offset();
- memory_.set_data_offset(offset);
memory_.set_cur_offset(offset);
- memory_.set_pc_offset(offset);
+ memory_.set_data_offset(offset);
+ pc_offset_ = offset;
return CreateSortedFdeList();
}
@@ -717,6 +719,7 @@
return false;
}
uint64_t value;
+ memory_.set_pc_offset(pc_offset_);
if (!memory_.template ReadEncodedValue<AddressType>(encoding, &value)) {
last_error_.code = DWARF_ERROR_MEMORY_INVALID;
last_error_.address = memory_.cur_offset();
@@ -737,15 +740,13 @@
}
uint64_t start;
- if (!memory_.template ReadEncodedValue<AddressType>(encoding & 0xf, &start)) {
- last_error_.code = DWARF_ERROR_MEMORY_INVALID;
- last_error_.address = memory_.cur_offset();
- return false;
- }
+ memory_.set_pc_offset(load_bias_);
+ bool valid = memory_.template ReadEncodedValue<AddressType>(encoding, &start);
start = AdjustPcFromFde(start);
uint64_t length;
- if (!memory_.template ReadEncodedValue<AddressType>(encoding & 0xf, &length)) {
+ memory_.set_pc_offset(0);
+ if (!valid || !memory_.template ReadEncodedValue<AddressType>(encoding, &length)) {
last_error_.code = DWARF_ERROR_MEMORY_INVALID;
last_error_.address = memory_.cur_offset();
return false;
@@ -877,7 +878,7 @@
while (first < last) {
size_t current = (first + last) / 2;
const FdeInfo* info = &fdes_[current];
- if (pc >= info->start && pc <= info->end) {
+ if (pc >= info->start && pc < info->end) {
*fde_offset = info->offset;
return true;
}