Enable reading DWARF4 CIEs with 32 bit addresses.
- 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>
diff --git a/src/common/dwarf/dwarf2reader.cc b/src/common/dwarf/dwarf2reader.cc
index 27f3a83..3e6a3e8 100644
--- a/src/common/dwarf/dwarf2reader.cc
+++ b/src/common/dwarf/dwarf2reader.cc
@@ -2330,21 +2330,15 @@
}
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 @@
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;
diff --git a/src/common/dwarf/dwarf2reader.h b/src/common/dwarf/dwarf2reader.h
index cf3ba3c..902d9ef 100644
--- a/src/common/dwarf/dwarf2reader.h
+++ b/src/common/dwarf/dwarf2reader.h
@@ -999,6 +999,11 @@
// or not we saw a 'z' augmentation string; its default value is
// DW_EH_PE_absptr, which is what normal DWARF CFI uses.
DwarfPointerEncoding pointer_encoding;
+
+ // These were only introduced in DWARF4, so will not be set in older
+ // versions.
+ uint8 address_size;
+ uint8 segment_size;
};
// A frame description entry (FDE).
diff --git a/src/common/dwarf/dwarf2reader_cfi_unittest.cc b/src/common/dwarf/dwarf2reader_cfi_unittest.cc
index 38cc7ea..35d4f34 100644
--- a/src/common/dwarf/dwarf2reader_cfi_unittest.cc
+++ b/src/common/dwarf/dwarf2reader_cfi_unittest.cc
@@ -608,11 +608,11 @@
}
TEST_F(CFI, CIEVersion4AdditionalFields) {
- CFISection section(kBigEndian, 4);
+ CFISection section(kBigEndian, 8);
Label cie;
section
.Mark(&cie)
- // CIE version 4 with expected address and segment size.
+ // CIE version 4 with expected address (64bit) and segment size.
.CIEHeader(0x0ab4758d, 0xc010fdf7, 0x89, 4, "", true, 8, 0)
.FinishEntry()
// FDE, citing that CIE.
@@ -631,7 +631,36 @@
string contents;
EXPECT_TRUE(section.GetContents(&contents));
ByteReader byte_reader(ENDIANNESS_BIG);
- byte_reader.SetAddressSize(4);
+ CallFrameInfo parser(reinterpret_cast<const uint8_t *>(contents.data()),
+ contents.size(),
+ &byte_reader, &handler, &reporter);
+ EXPECT_TRUE(parser.Start());
+}
+
+TEST_F(CFI, CIEVersion4AdditionalFields32BitAddress) {
+ CFISection section(kBigEndian, 4);
+ Label cie;
+ section
+ .Mark(&cie)
+ // CIE version 4 with expected address (32bit) and segment size.
+ .CIEHeader(0x0ab4758d, 0xc010fdf7, 0x89, 4, "", true, 4, 0)
+ .FinishEntry()
+ // FDE, citing that CIE.
+ .FDEHeader(cie, 0x86763f2b, 0x2a66dc23)
+ .FinishEntry();
+
+ PERHAPS_WRITE_DEBUG_FRAME_FILE("CIEVersion3ReturnColumn", section);
+
+ {
+ InSequence s;
+ EXPECT_CALL(handler, Entry(_, 0x86763f2b, 0x2a66dc23, 4, "", 0x89))
+ .WillOnce(Return(true));
+ EXPECT_CALL(handler, End()).WillOnce(Return(true));
+ }
+
+ string contents;
+ EXPECT_TRUE(section.GetContents(&contents));
+ ByteReader byte_reader(ENDIANNESS_BIG);
CallFrameInfo parser(reinterpret_cast<const uint8_t *>(contents.data()),
contents.size(),
&byte_reader, &handler, &reporter);
@@ -659,7 +688,6 @@
string contents;
EXPECT_TRUE(section.GetContents(&contents));
ByteReader byte_reader(ENDIANNESS_BIG);
- byte_reader.SetAddressSize(8);
CallFrameInfo parser(reinterpret_cast<const uint8_t *>(contents.data()),
contents.size(),
&byte_reader, &handler, &reporter);
@@ -667,7 +695,7 @@
}
TEST_F(CFI, CIEVersion4AdditionalFieldsUnexpectedSegmentSize) {
- CFISection section(kBigEndian, 4);
+ CFISection section(kBigEndian, 8);
Label cie;
section
@@ -685,7 +713,6 @@
string contents;
EXPECT_TRUE(section.GetContents(&contents));
ByteReader byte_reader(ENDIANNESS_BIG);
- byte_reader.SetAddressSize(8);
CallFrameInfo parser(reinterpret_cast<const uint8_t *>(contents.data()),
contents.size(),
&byte_reader, &handler, &reporter);
