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Enable reading DWARF4 CIEs with 32 bit addresses.

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- Reading DWARF4 CIEs was added in
https://chromium-review.googlesource.com/c/breakpad/breakpad/+/406012 but it
was only enabled for 64bit builds, since it would error out if the CIE
address size was not 8 bytes.
- Added a unit test to ensure that 32bit continues to work.

Change-Id: I824bb40cdf12056d39da335adb55ed315970fb88
Reviewed-on: https://chromium-review.googlesource.com/c/breakpad/breakpad/+/1941034
Reviewed-by: Ivan Penkov <ivanpe@chromium.org>
Reviewed-by: Mark Mentovai <mark@chromium.org>
This commit is contained in:
Nelson Billing 2019-12-03 15:00:30 -08:00
parent 5bc3092b30
commit f32b83eb08
3 changed files with 53 additions and 18 deletions
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27
src/common/dwarf/dwarf2reader.cc
View file

@ -2330,21 +2330,15 @@ bool CallFrameInfo::ReadCIEFields(CIE *cie) {
}
if (cie->version >= 4) {
uint8_t address_size = *cursor++;
if (address_size != 8) {
// TODO(scottmg): Only supporting x64 for now.
reporter_->UnexpectedAddressSize(cie->offset, address_size);
cie->address_size = *cursor++;
if (cie->address_size != 8 && cie->address_size != 4) {
reporter_->UnexpectedAddressSize(cie->offset, cie->address_size);
return false;
}
uint8_t segment_size = *cursor++;
if (segment_size != 0) {
// TODO(scottmg): Only supporting x64 for now.
// I would have perhaps expected 4 here, but LLVM emits a 0, near
// http://llvm.org/docs/doxygen/html/MCDwarf_8cpp_source.html#l00606. As
// we are not using the value, only succeed for now if it's the expected
// 0.
reporter_->UnexpectedSegmentSize(cie->offset, segment_size);
cie->segment_size = *cursor++;
if (cie->segment_size != 0) {
reporter_->UnexpectedSegmentSize(cie->offset, cie->segment_size);
return false;
}
}
@ -2606,6 +2600,15 @@ bool CallFrameInfo::Start() {
if (!ReadCIEFields(&cie))
continue;
// TODO(nbilling): This could lead to strange behavior if a single buffer
// contained a mixture of DWARF versions as well as address sizes. Not
// sure if it's worth handling such a case.
// DWARF4 CIE specifies address_size, so use it for this call frame.
if (cie.version >= 4) {
reader_->SetAddressSize(cie.address_size);
}
// We now have the values that govern both the CIE and the FDE.
cie.cie = &cie;
fde.cie = &cie;