From 8efe0f1c3b45b79bab3046c0776283a2bdf6193f Mon Sep 17 00:00:00 2001 From: Sterling Augustine Date: Thu, 25 Jun 2020 14:55:48 -0700 Subject: Read dwarf5 compilation unit headers. Change-Id: Ia85b2fb7b3cb821ad353a0003223d8b8465e792d Reviewed-on: https://chromium-review.googlesource.com/c/breakpad/breakpad/+/2265259 Reviewed-by: Mike Frysinger Reviewed-by: Mark Mentovai --- src/common/dwarf/dwarf2enums.h | 10 +++ src/common/dwarf/dwarf2reader.cc | 90 ++++++++++++++++++++++----- src/common/dwarf/dwarf2reader.h | 21 +++++++ src/common/dwarf/dwarf2reader_die_unittest.cc | 6 +- src/common/dwarf/dwarf2reader_test_common.h | 12 +++- 5 files changed, 119 insertions(+), 20 deletions(-) diff --git a/src/common/dwarf/dwarf2enums.h b/src/common/dwarf/dwarf2enums.h index bed70327..2b93aba7 100644 --- a/src/common/dwarf/dwarf2enums.h +++ b/src/common/dwarf/dwarf2enums.h @@ -115,6 +115,16 @@ enum DwarfTag { DW_TAG_PGI_interface_block = 0xA020 }; +enum DwarfUnitHeader { + DW_UT_compile = 0x01, + DW_UT_type = 0x02, + DW_UT_partial = 0x03, + DW_UT_skeleton = 0x04, + DW_UT_split_compile = 0x05, + DW_UT_split_type = 0x06, + DW_UT_lo_user = 0x80, + DW_UT_hi_user = 0xFF +}; enum DwarfHasChild { DW_children_no = 0, diff --git a/src/common/dwarf/dwarf2reader.cc b/src/common/dwarf/dwarf2reader.cc index fbfff275..138f9200 100644 --- a/src/common/dwarf/dwarf2reader.cc +++ b/src/common/dwarf/dwarf2reader.cc @@ -253,11 +253,50 @@ const uint8_t *CompilationUnit::SkipAttribute(const uint8_t *start, return NULL; } -// Read a DWARF2/3 header. -// The header is variable length in DWARF3 (and DWARF2 as extended by -// most compilers), and consists of an length field, a version number, -// the offset in the .debug_abbrev section for our abbrevs, and an -// address size. +// Read the abbreviation offset from a compilation unit header. +size_t CompilationUnit::ReadAbbrevOffset(const uint8_t* headerptr) { + assert(headerptr + reader_->OffsetSize() < buffer_ + buffer_length_); + header_.abbrev_offset = reader_->ReadOffset(headerptr); + return reader_->OffsetSize(); +} + +// Read the address size from a compilation unit header. +size_t CompilationUnit::ReadAddressSize(const uint8_t* headerptr) { + // Compare against less than or equal because this may be the last + // section in the file. + assert(headerptr + 1 <= buffer_ + buffer_length_); + header_.address_size = reader_->ReadOneByte(headerptr); + reader_->SetAddressSize(header_.address_size); + return 1; +} + +// Read the DWO id from a split or skeleton compilation unit header. +size_t CompilationUnit::ReadDwoId(const uint8_t* headerptr) { + assert(headerptr + 8 <= buffer_ + buffer_length_); + dwo_id_ = reader_->ReadEightBytes(headerptr); + return 8; +} + +// Read the type signature from a type or split type compilation unit header. +size_t CompilationUnit::ReadTypeSignature(const uint8_t* headerptr) { + assert(headerptr + 8 <= buffer_ + buffer_length_); + type_signature_ = reader_->ReadEightBytes(headerptr); + return 8; +} + +// Read the DWO id from a split or skeleton compilation unit header. +size_t CompilationUnit::ReadTypeOffset(const uint8_t* headerptr) { + assert(headerptr + reader_->OffsetSize() < buffer_ + buffer_length_); + type_offset_ = reader_->ReadOffset(headerptr); + return reader_->OffsetSize(); +} + + +// Read a DWARF header. The header is variable length in DWARF3 and DWARF4 +// (and DWARF2 as extended by most compilers), and consists of an length +// field, a version number, the offset in the .debug_abbrev section for our +// abbrevs, and an address size. DWARF5 adds a unit_type to distinguish +// between partial-, full-, skeleton-, split-, and type- compilation units. void CompilationUnit::ReadHeader() { const uint8_t *headerptr = buffer_; size_t initial_length_size; @@ -272,17 +311,36 @@ void CompilationUnit::ReadHeader() { header_.version = reader_->ReadTwoBytes(headerptr); headerptr += 2; - assert(headerptr + reader_->OffsetSize() < buffer_ + buffer_length_); - header_.abbrev_offset = reader_->ReadOffset(headerptr); - headerptr += reader_->OffsetSize(); - - // Compare against less than or equal because this may be the last - // section in the file. - assert(headerptr + 1 <= buffer_ + buffer_length_); - header_.address_size = reader_->ReadOneByte(headerptr); - reader_->SetAddressSize(header_.address_size); - headerptr += 1; - + if (header_.version <= 4) { + // Older versions of dwarf have a relatively simple structure. + headerptr += ReadAbbrevOffset(headerptr); + headerptr += ReadAddressSize(headerptr); + } else { + // DWARF5 adds a unit_type field, and various fields based on unit_type. + assert(headerptr + 1 < buffer_ + buffer_length_); + uint8_t unit_type = reader_->ReadOneByte(headerptr); + headerptr += 1; + headerptr += ReadAddressSize(headerptr); + headerptr += ReadAbbrevOffset(headerptr); + switch (unit_type) { + case DW_UT_compile: + case DW_UT_partial: + // nothing else to read + break; + case DW_UT_skeleton: + case DW_UT_split_compile: + headerptr += ReadDwoId(headerptr); + break; + case DW_UT_type: + case DW_UT_split_type: + headerptr += ReadTypeSignature(headerptr); + headerptr += ReadTypeOffset(headerptr); + break; + default: + fprintf(stderr, "Unhandled compilation unit type 0x%x", unit_type); + break; + } + } after_header_ = headerptr; // This check ensures that we don't have to do checking during the diff --git a/src/common/dwarf/dwarf2reader.h b/src/common/dwarf/dwarf2reader.h index 593f5c0c..cd91b107 100644 --- a/src/common/dwarf/dwarf2reader.h +++ b/src/common/dwarf/dwarf2reader.h @@ -411,6 +411,21 @@ class CompilationUnit { // Reads the DWARF2/3 abbreviations for this compilation unit void ReadAbbrevs(); + // Read the abbreviation offset for this compilation unit + size_t ReadAbbrevOffset(const uint8_t* headerptr); + + // Read the address size for this compilation unit + size_t ReadAddressSize(const uint8_t* headerptr); + + // Read the DWO id from a split or skeleton compilation unit header + size_t ReadDwoId(const uint8_t* headerptr); + + // Read the type signature from a type or split type compilation unit header + size_t ReadTypeSignature(const uint8_t* headerptr); + + // Read the DWO id from a split or skeleton compilation unit header + size_t ReadTypeOffset(const uint8_t* headerptr); + // Processes a single DIE for this compilation unit and return a new // pointer just past the end of it const uint8_t *ProcessDIE(uint64_t dieoffset, @@ -603,6 +618,12 @@ class CompilationUnit { // The value of the DW_AT_GNU_dwo_id attribute, if any. uint64_t dwo_id_; + // The value of the DW_AT_GNU_type_signature attribute, if any. + uint64_t type_signature_; + + // The value of the DW_AT_GNU_type_offset attribute, if any. + size_t type_offset_; + // The value of the DW_AT_GNU_dwo_name attribute, if any. const char* dwo_name_; diff --git a/src/common/dwarf/dwarf2reader_die_unittest.cc b/src/common/dwarf/dwarf2reader_die_unittest.cc index ca44cad0..ab9f7cb7 100644 --- a/src/common/dwarf/dwarf2reader_die_unittest.cc +++ b/src/common/dwarf/dwarf2reader_die_unittest.cc @@ -218,6 +218,8 @@ INSTANTIATE_TEST_CASE_P( DwarfHeaderParams(kLittleEndian, 8, 3, 8), DwarfHeaderParams(kLittleEndian, 8, 4, 4), DwarfHeaderParams(kLittleEndian, 8, 4, 8), + DwarfHeaderParams(kLittleEndian, 8, 5, 4), + DwarfHeaderParams(kLittleEndian, 8, 5, 8), DwarfHeaderParams(kBigEndian, 4, 2, 4), DwarfHeaderParams(kBigEndian, 4, 2, 8), DwarfHeaderParams(kBigEndian, 4, 3, 4), @@ -229,7 +231,9 @@ INSTANTIATE_TEST_CASE_P( DwarfHeaderParams(kBigEndian, 8, 3, 4), DwarfHeaderParams(kBigEndian, 8, 3, 8), DwarfHeaderParams(kBigEndian, 8, 4, 4), - DwarfHeaderParams(kBigEndian, 8, 4, 8))); + DwarfHeaderParams(kBigEndian, 8, 4, 8), + DwarfHeaderParams(kBigEndian, 8, 5, 4), + DwarfHeaderParams(kBigEndian, 8, 5, 8))); struct DwarfFormsFixture: public DIEFixture { // Start a compilation unit, as directed by |params|, containing one diff --git a/src/common/dwarf/dwarf2reader_test_common.h b/src/common/dwarf/dwarf2reader_test_common.h index e91de906..c81d54a8 100644 --- a/src/common/dwarf/dwarf2reader_test_common.h +++ b/src/common/dwarf/dwarf2reader_test_common.h @@ -57,7 +57,7 @@ class TestCompilationUnit: public google_breakpad::test_assembler::Section { assert(format_size == 4 || format_size == 8); format_size_ = format_size; } - + // Append a DWARF section offset value, of the appropriate size for this // compilation unit. template @@ -80,8 +80,14 @@ class TestCompilationUnit: public google_breakpad::test_assembler::Section { } post_length_offset_ = Size(); D16(version); - SectionOffset(abbrev_offset); - D8(address_size); + if (version <= 4) { + SectionOffset(abbrev_offset); + D8(address_size); + } else { + D8(0x01); // DW_UT_compile + D8(address_size); + SectionOffset(abbrev_offset); + } return *this; } -- cgit v1.2.1