[MachO] Add a test for detecting reserved unit length.

[ikudrin]

Summary

This is a follow-up for D71546 to add a corresponding unit test.

[hctim]

This test broke the UBSan buildbot here. I've rolled it back for now, but to reproduce the issue should be as simple as adding -DLLVM_USE_SANITIZER=Undefined and running ninja check-lld or make check-lld depending on which tool you use :)

[ RUN      ] ToAtomsTest.reservedUnitLength
/b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm-project/lld/lib/ReaderWriter/MachO/MachONormalizedFileToAtoms.cpp:972:35: runtime error: reference binding to null pointer of type 'const lld::mach_o::normalized::Section'
    #0 0x509684 in parseDebugInfo /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm-project/lld/lib/ReaderWriter/MachO/MachONormalizedFileToAtoms.cpp:971:22
    #1 0x509684 in lld::mach_o::normalized::normalizedObjectToAtoms(lld::mach_o::MachOFile*, lld::mach_o::normalized::NormalizedFile const&, bool) /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm-project/lld/lib/ReaderWriter/MachO/MachONormalizedFileToAtoms.cpp:1553:18
    #2 0x50a6f5 in objectToAtoms /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm-project/lld/lib/ReaderWriter/MachO/MachONormalizedFileToAtoms.cpp:1405:17
    #3 0x50a6f5 in lld::mach_o::normalized::normalizedToAtoms(lld::mach_o::normalized::NormalizedFile const&, llvm::StringRef, bool) /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm-project/lld/lib/ReaderWriter/MachO/MachONormalizedFileToAtoms.cpp:1626:12
    #4 0x45811f in ToAtomsTest_reservedUnitLength_Test::TestBody() /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm-project/lld/unittests/MachOTests/MachONormalizedFileToAtomsTests.cpp:126:31
    #5 0x4d250b in testing::Test::Run() /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm-project/llvm/utils/unittest/googletest/src/gtest.cc:2474:5
    #6 0x4d31fa in testing::TestInfo::Run() /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm-project/llvm/utils/unittest/googletest/src/gtest.cc:2656:11
    #7 0x4d3bc2 in testing::TestCase::Run() /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm-project/llvm/utils/unittest/googletest/src/gtest.cc:2774:28
    #8 0x4db1d2 in testing::internal::UnitTestImpl::RunAllTests() /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm-project/llvm/utils/unittest/googletest/src/gtest.cc:4649:43
    #9 0x4dac55 in testing::UnitTest::Run() /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm-project/llvm/utils/unittest/googletest/src/gtest.cc:4257:10
    #10 0x4cab63 in RUN_ALL_TESTS /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm-project/llvm/utils/unittest/googletest/include/gtest/gtest.h:2233:46
    #11 0x4cab63 in main /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm-project/llvm/utils/unittest/UnitTestMain/TestMain.cpp:50:10
    #12 0x7fbfa7f842e0 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x202e0)
    #13 0x40e909 in _start (/b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build_ubsan/tools/lld/unittests/MachOTests/lldMachOTests+0x40e909)

SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm-project/lld/lib/ReaderWriter/MachO/MachONormalizedFileToAtoms.cpp:972:35 in

[ikudrin]

Thank you! I'll fix that. For some reason, I did not receive the notification from the build bot.

[dblaikie]

In D72695#1830559, @ikudrin wrote:

Thank you! I'll fix that. For some reason, I did not receive the notification from the build bot.

Did this get fixed? In what revision? (it's nice to follow-up on these threads to include where the fix was made so others can check back to see if they've picked up the fix, etc)

[ikudrin]

In D72695#1850551, @dblaikie wrote:

In D72695#1830559, @ikudrin wrote:

Thank you! I'll fix that. For some reason, I did not receive the notification from the build bot.

Did this get fixed? In what revision? (it's nice to follow-up on these threads to include where the fix was made so others can check back to see if they've picked up the fix, etc)

The fix commit references this review, so it is mentioned in the header, in Detail/Commits section. Well, maybe that is not that clear as I expected. https://reviews.llvm.org/rG6b4f86f65f165249cbea1d23611ac97aeec7a082

[dblaikie]

In D72695#1850839, @ikudrin wrote:

In D72695#1850551, @dblaikie wrote:

In D72695#1830559, @ikudrin wrote:

Thank you! I'll fix that. For some reason, I did not receive the notification from the build bot.

Did this get fixed? In what revision? (it's nice to follow-up on these threads to include where the fix was made so others can check back to see if they've picked up the fix, etc)

The fix commit references this review, so it is mentioned in the header, in Detail/Commits section. Well, maybe that is not that clear as I expected. https://reviews.llvm.org/rG6b4f86f65f165249cbea1d23611ac97aeec7a082

Ah, indeed - thanks for the pointers!

lld/unittests/MachOTests/MachONormalizedFileToAtomsTests.cpp

TEST(ToAtomsTest, basic_obj_x86_64) {
   EXPECT_TRUE(atom3->name().equals("_baz"));
   EXPECT_EQ(1U, atom3->rawContent().size());
   EXPECT_EQ(0xC4, atom3->rawContent()[0]);
   EXPECT_EQ(lld::Atom::scopeLinkageUnit, atom3->scope());
 
   EXPECT_TRUE(atom4->name().equals("_undef"));
   EXPECT_EQ(lld::Atom::definitionUndefined, atom4->definition());
 }
+
+TEST(ToAtomsTest, reservedUnitLength) {
+  static const uint8_t debugInfoWithReservedLengthContent[12] = {
+      0xf0, 0xff, 0xff, 0xff // Reserved length value
+  };
+  static const uint8_t debugInfoWithValidBigLengthContent[12] = {
+      0xef, 0xff, 0xff, 0xff, // The maximum valid length value for DWARF32
+      0x00, 0x00              // Wrong version
+  };
+  static const uint8_t debugAbbrevDummyContent[] = {0x00};
+
+  NormalizedFile fReservedLength, fValidBigLength;
+  fReservedLength.arch = lld::MachOLinkingContext::arch_x86;
+  fValidBigLength.arch = lld::MachOLinkingContext::arch_x86;
+  Section section;
+  section.segmentName = "__DWARF";
+  section.sectionName = "__debug_info";
+  section.content = llvm::makeArrayRef(debugInfoWithReservedLengthContent);
+  fReservedLength.sections.push_back(section);
+  section.content = llvm::makeArrayRef(debugInfoWithValidBigLengthContent);
+  fValidBigLength.sections.push_back(section);
+  section.sectionName = "__debug_abbrev";
+  section.content = llvm::makeArrayRef(debugAbbrevDummyContent);
+  fReservedLength.sections.push_back(section);
+  fValidBigLength.sections.push_back(section);
+
+  auto resultReservedLength = normalizedToAtoms(fReservedLength, "foo", false);
+  auto resultValidBigLength = normalizedToAtoms(fValidBigLength, "foo", false);
+
+  // Both cases should return errors, but different.
+  ASSERT_FALSE(resultReservedLength);
+  ASSERT_FALSE(resultValidBigLength);
+
+  EXPECT_STREQ("Malformed DWARF in foo",
+               toString(resultReservedLength.takeError()).c_str());
+  EXPECT_STREQ("Unsupported DWARF version in foo",
+               toString(resultValidBigLength.takeError()).c_str());
+}