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Merge commit '393eac16e497' from llvm.org/release/11.x into apple/stable/20200714
2 parents e52945e + 393eac1 commit f571cb9

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‎lldb/source/Plugins/Process/minidump/ProcessMinidump.cpp

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@@ -121,6 +121,72 @@ class PlaceholderObjectFile : public ObjectFile {
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lldb::addr_t m_base;
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lldb::addr_t m_size;
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};
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/// Duplicate the HashElfTextSection() from the breakpad sources.
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///
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/// Breakpad, a Google crash log reporting tool suite, creates minidump files
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/// for many different architectures. When using Breakpad to create ELF
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/// minidumps, it will check for a GNU build ID when creating a minidump file
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/// and if one doesn't exist in the file, it will say the UUID of the file is a
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/// checksum of up to the first 4096 bytes of the .text section. Facebook also
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/// uses breakpad and modified this hash to avoid collisions so we can
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/// calculate and check for this as well.
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///
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/// The breakpad code might end up hashing up to 15 bytes that immediately
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/// follow the .text section in the file, so this code must do exactly what it
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/// does so we can get an exact match for the UUID.
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///
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/// \param[in] module_sp The module to grab the .text section from.
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///
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/// \param[in/out] breakpad_uuid A vector that will receive the calculated
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/// breakpad .text hash.
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///
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/// \param[in/out] facebook_uuid A vector that will receive the calculated
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/// facebook .text hash.
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///
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void HashElfTextSection(ModuleSP module_sp, std::vector<uint8_t> &breakpad_uuid,
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std::vector<uint8_t> &facebook_uuid) {
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SectionList *sect_list = module_sp->GetSectionList();
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if (sect_list == nullptr)
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return;
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SectionSP sect_sp = sect_list->FindSectionByName(ConstString(".text"));
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if (!sect_sp)
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return;
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constexpr size_t kMDGUIDSize = 16;
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constexpr size_t kBreakpadPageSize = 4096;
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// The breakpad code has a bug where it might access beyond the end of a
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// .text section by up to 15 bytes, so we must ensure we round up to the
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// next kMDGUIDSize byte boundary.
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DataExtractor data;
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const size_t text_size = sect_sp->GetFileSize();
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const size_t read_size = std::min<size_t>(
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llvm::alignTo(text_size, kMDGUIDSize), kBreakpadPageSize);
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sect_sp->GetObjectFile()->GetData(sect_sp->GetFileOffset(), read_size, data);
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breakpad_uuid.assign(kMDGUIDSize, 0);
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facebook_uuid.assign(kMDGUIDSize, 0);
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// The only difference between the breakpad hash and the facebook hash is the
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// hashing of the text section size into the hash prior to hashing the .text
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// contents.
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for (size_t i = 0; i < kMDGUIDSize; i++)
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facebook_uuid[i] ^= text_size % 255;
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// This code carefully duplicates how the hash was created in Breakpad
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// sources, including the error where it might has an extra 15 bytes past the
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// end of the .text section if the .text section is less than a page size in
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// length.
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const uint8_t *ptr = data.GetDataStart();
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const uint8_t *ptr_end = data.GetDataEnd();
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while (ptr < ptr_end) {
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for (unsigned i = 0; i < kMDGUIDSize; i++) {
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breakpad_uuid[i] ^= ptr[i];
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facebook_uuid[i] ^= ptr[i];
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}
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ptr += kMDGUIDSize;
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}
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}
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} // namespace
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ConstString ProcessMinidump::GetPluginNameStatic() {
@@ -494,10 +560,33 @@ void ProcessMinidump::ReadModuleList() {
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const bool match = dmp_bytes.empty() || mod_bytes.empty() ||
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mod_bytes.take_front(dmp_bytes.size()) == dmp_bytes;
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if (!match) {
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// Breakpad generates minindump files, and if there is no GNU build
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// ID in the binary, it will calculate a UUID by hashing first 4096
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// bytes of the .text section and using that as the UUID for a module
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// in the minidump. Facebook uses a modified breakpad client that
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// uses a slightly modified this hash to avoid collisions. Check for
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// UUIDs from the minindump that match these cases and accept the
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// module we find if they do match.
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std::vector<uint8_t> breakpad_uuid;
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std::vector<uint8_t> facebook_uuid;
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HashElfTextSection(module_sp, breakpad_uuid, facebook_uuid);
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if (dmp_bytes == llvm::ArrayRef<uint8_t>(breakpad_uuid)) {
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LLDB_LOG(log, "Breakpad .text hash match for {0}.", name);
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} else if (dmp_bytes == llvm::ArrayRef<uint8_t>(facebook_uuid)) {
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LLDB_LOG(log, "Facebook .text hash match for {0}.", name);
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} else {
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// The UUID wasn't a partial match and didn't match the .text hash
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// so remove the module from the target, we will need to create a
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// placeholder object file.
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GetTarget().GetImages().Remove(module_sp);
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module_sp.reset();
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}
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} else {
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LLDB_LOG(log, "Partial uuid match for {0}.", name);
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}
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}
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} else {
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LLDB_LOG(log, "Full uuid match for {0}.", name);
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}
502591
if (module_sp) {
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// Watch out for place holder modules that have different paths, but the

‎lldb/test/API/functionalities/postmortem/minidump-new/TestMiniDumpUUID.py

Lines changed: 63 additions & 0 deletions
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@@ -179,6 +179,69 @@ def test_partial_uuid_mismatch(self):
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"/invalid/path/on/current/system/libuuidmismatch.so",
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"7295E17C-6668-9E05-CBB5-DEE5003865D5")
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def test_breakpad_hash_match(self):
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"""
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Breakpad creates minidump files using CvRecord in each module whose
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signature is set to PDB70 where the UUID is a hash generated by
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breakpad of the .text section. This is only done when the
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executable has no ELF build ID.
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This test verifies that if we have a minidump with a 16 byte UUID,
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that we are able to associate a symbol file with no ELF build ID
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and match it up by hashing the .text section.
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"""
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so_path = self.getBuildArtifact("libbreakpad.so")
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self.yaml2obj("libbreakpad.yaml", so_path)
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cmd = 'settings set target.exec-search-paths "%s"' % (os.path.dirname(so_path))
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self.dbg.HandleCommand(cmd)
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modules = self.get_minidump_modules("linux-arm-breakpad-uuid-match.yaml")
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self.assertEqual(1, len(modules))
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# LLDB makes up it own UUID as well when there is no build ID so we
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# will check that this matches.
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self.verify_module(modules[0], so_path, "D9C480E8")
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def test_breakpad_overflow_hash_match(self):
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"""
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This is a similar to test_breakpad_hash_match, but it verifies that
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if the .text section does not end on a 16 byte boundary, then it
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will overflow into the next section's data by up to 15 bytes. This
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verifies that we are able to match what breakpad does as it will do
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this.
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"""
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so_path = self.getBuildArtifact("libbreakpad.so")
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self.yaml2obj("libbreakpad-overflow.yaml", so_path)
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cmd = 'settings set target.exec-search-paths "%s"' % (os.path.dirname(so_path))
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self.dbg.HandleCommand(cmd)
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modules = self.get_minidump_modules("linux-arm-breakpad-uuid-match.yaml")
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self.assertEqual(1, len(modules))
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# LLDB makes up it own UUID as well when there is no build ID so we
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# will check that this matches.
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self.verify_module(modules[0], so_path, "48EB9FD7")
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def test_facebook_hash_match(self):
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"""
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Breakpad creates minidump files using CvRecord in each module whose
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signature is set to PDB70 where the UUID is a hash generated by
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breakpad of the .text section and Facebook modified this hash to
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avoid collisions. This is only done when the executable has no ELF
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build ID.
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This test verifies that if we have a minidump with a 16 byte UUID,
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that we are able to associate a symbol file with no ELF build ID
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and match it up by hashing the .text section like Facebook does.
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"""
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so_path = self.getBuildArtifact("libbreakpad.so")
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self.yaml2obj("libbreakpad.yaml", so_path)
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cmd = 'settings set target.exec-search-paths "%s"' % (os.path.dirname(so_path))
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self.dbg.HandleCommand(cmd)
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modules = self.get_minidump_modules("linux-arm-facebook-uuid-match.yaml")
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self.assertEqual(1, len(modules))
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# LLDB makes up it own UUID as well when there is no build ID so we
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# will check that this matches.
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self.verify_module(modules[0], so_path, "D9C480E8")
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def test_relative_module_name(self):
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old_cwd = os.getcwd()
184247
self.addTearDownHook(lambda: os.chdir(old_cwd))

‎lldb/test/API/functionalities/postmortem/minidump-new/libbreakpad-overflow.yaml

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@@ -0,0 +1,21 @@
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--- !ELF
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FileHeader:
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Class: ELFCLASS32
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Data: ELFDATA2LSB
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Type: ET_DYN
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Machine: EM_ARM
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Flags: [ EF_ARM_SOFT_FLOAT, EF_ARM_EABI_VER5 ]
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Sections:
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Sections:
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- Name: .text
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Type: SHT_PROGBITS
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Flags: [ SHF_ALLOC, SHF_EXECINSTR ]
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Address: 0x0000000000010000
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AddressAlign: 0x0000000000000001
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Content: 04
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- Name: .data
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Type: SHT_PROGBITS
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Flags: [ SHF_ALLOC, SHF_WRITE ]
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Address: 0x0000000000010001
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AddressAlign: 0x0000000000000001
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Content: 0000001400000003000000474E5500

‎lldb/test/API/functionalities/postmortem/minidump-new/libbreakpad.yaml

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@@ -0,0 +1,15 @@
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--- !ELF
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FileHeader:
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Class: ELFCLASS32
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Data: ELFDATA2LSB
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Type: ET_DYN
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Machine: EM_ARM
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Flags: [ EF_ARM_SOFT_FLOAT, EF_ARM_EABI_VER5 ]
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Sections:
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Sections:
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- Name: .text
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Type: SHT_PROGBITS
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Flags: [ SHF_ALLOC, SHF_EXECINSTR ]
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Address: 0x0000000000010000
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AddressAlign: 0x0000000000000004
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Content: 040000001400000003000000474E5500

‎lldb/test/API/functionalities/postmortem/minidump-new/linux-arm-breakpad-uuid-match.yaml

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--- !minidump
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Streams:
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- Type: SystemInfo
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Processor Arch: ARM
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Platform ID: Linux
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CSD Version: '15E216'
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CPU:
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CPUID: 0x00000000
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- Type: ModuleList
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Modules:
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- Base of Image: 0x0000000000001000
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Size of Image: 0x00001000
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Module Name: '/invalid/path/on/current/system/libbreakpad.so'
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CodeView Record: 52534453040000001400000003000000474e55000000000000
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...

‎lldb/test/API/functionalities/postmortem/minidump-new/linux-arm-facebook-uuid-match.yaml

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--- !minidump
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Streams:
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- Type: SystemInfo
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Processor Arch: ARM
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Platform ID: Linux
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CSD Version: '15E216'
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CPU:
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CPUID: 0x00000000
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- Type: ModuleList
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Modules:
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- Base of Image: 0x0000000000001000
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Size of Image: 0x00001000
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Module Name: '/invalid/path/on/current/system/libbreakpad.so'
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CodeView Record: 52534453141010100410101013101010575e45100000000000
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...

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