[llvm] llvm-gsymutil now handles empty linkage names correctly. (PR #68931)
Greg Clayton via llvm-commits
llvm-commits at lists.llvm.org
Mon Oct 16 16:20:52 PDT 2023
https://github.com/clayborg updated https://github.com/llvm/llvm-project/pull/68931
>From 5c2dfa575e60e141d4e09f9d1d66e3d0238a1df0 Mon Sep 17 00:00:00 2001
From: Greg Clayton <gclayton at fb.com>
Date: Thu, 12 Oct 2023 14:26:32 -0700
Subject: [PATCH] llvm-gsymutil now handles empty linkage names correctly.
Previous to this fix, if we had a DW_TAG_subprogram that had a DW_AT_linkage_name that was empty, it would attempt to use this name which would cause an error to be emitted when saving the gsym file to disk:
error: DWARF conversion failed: : attempted to encode invalid FunctionInfo object
This patch fixes this issue and adds a unit test case.
---
llvm/lib/DebugInfo/GSYM/DwarfTransformer.cpp | 10 +-
llvm/unittests/DebugInfo/GSYM/GSYMTest.cpp | 152 +++++++++++++++++++
2 files changed, 157 insertions(+), 5 deletions(-)
diff --git a/llvm/lib/DebugInfo/GSYM/DwarfTransformer.cpp b/llvm/lib/DebugInfo/GSYM/DwarfTransformer.cpp
index e38347f15e3ae8b..d720c1e33495515 100644
--- a/llvm/lib/DebugInfo/GSYM/DwarfTransformer.cpp
+++ b/llvm/lib/DebugInfo/GSYM/DwarfTransformer.cpp
@@ -132,11 +132,11 @@ static DWARFDie GetParentDeclContextDIE(DWARFDie &Die) {
static std::optional<uint32_t>
getQualifiedNameIndex(DWARFDie &Die, uint64_t Language, GsymCreator &Gsym) {
// If the dwarf has mangled name, use mangled name
- if (auto LinkageName =
- dwarf::toString(Die.findRecursively({dwarf::DW_AT_MIPS_linkage_name,
- dwarf::DW_AT_linkage_name}),
- nullptr))
- return Gsym.insertString(LinkageName, /* Copy */ false);
+ if (auto LinkageName = Die.getLinkageName()) {
+ // We have seen cases were linkage name is actually empty.
+ if (strlen(LinkageName) > 0)
+ return Gsym.insertString(LinkageName, /* Copy */ false);
+ }
StringRef ShortName(Die.getName(DINameKind::ShortName));
if (ShortName.empty())
diff --git a/llvm/unittests/DebugInfo/GSYM/GSYMTest.cpp b/llvm/unittests/DebugInfo/GSYM/GSYMTest.cpp
index 58bc83997d1a926..ad81a2fcd16441a 100644
--- a/llvm/unittests/DebugInfo/GSYM/GSYMTest.cpp
+++ b/llvm/unittests/DebugInfo/GSYM/GSYMTest.cpp
@@ -4005,3 +4005,155 @@ TEST(GSYMTest, TestEmptyRangeWarnings) {
// Make sure we don't see spurious errors in the output:
EXPECT_TRUE(errors.find("error:") == std::string::npos);
}
+
+
+TEST(GSYMTest, TestEmptyLinkageName) {
+ // This example has a single compile unit that has a DW_TAG_subprogram that
+ // has a function that has an empty linkage name and a valid normal name.
+ // Previously this would cause an encoding error:
+ //
+ // DWARF conversion failed: attempted to encode invalid FunctionInfo object
+ //
+ // This was because we would get a valid but empty linkage name and we would
+ // try to use this in the GSYM FunctionInfo and that would cause the error
+ // as the name was empty.
+ //
+ // 0x0000000b: DW_TAG_compile_unit
+ // DW_AT_name ("/tmp/main.cpp")
+ // DW_AT_language (DW_LANG_C)
+ // DW_AT_stmt_list (0x00000000)
+ //
+ // 0x00000015: DW_TAG_subprogram
+ // DW_AT_name ("foo")
+ // DW_AT_linkage_name ("")
+ // DW_AT_low_pc (0x0000000000001000)
+ // DW_AT_high_pc (0x0000000000001050)
+ //
+ // 0x0000002e: NULL
+
+
+ StringRef yamldata = R"(
+ debug_str:
+ - ''
+ - '/tmp/main.cpp'
+ - foo
+ - ''
+ debug_abbrev:
+ - ID: 0
+ Table:
+ - Code: 0x1
+ Tag: DW_TAG_compile_unit
+ Children: DW_CHILDREN_yes
+ Attributes:
+ - Attribute: DW_AT_name
+ Form: DW_FORM_strp
+ - Attribute: DW_AT_language
+ Form: DW_FORM_udata
+ - Attribute: DW_AT_stmt_list
+ Form: DW_FORM_sec_offset
+ - Code: 0x2
+ Tag: DW_TAG_subprogram
+ Children: DW_CHILDREN_no
+ Attributes:
+ - Attribute: DW_AT_name
+ Form: DW_FORM_strp
+ - Attribute: DW_AT_linkage_name
+ Form: DW_FORM_strp
+ - Attribute: DW_AT_low_pc
+ Form: DW_FORM_addr
+ - Attribute: DW_AT_high_pc
+ Form: DW_FORM_addr
+ debug_info:
+ - Length: 0x2B
+ Version: 4
+ AbbrevTableID: 0
+ AbbrOffset: 0x0
+ AddrSize: 8
+ Entries:
+ - AbbrCode: 0x1
+ Values:
+ - Value: 0x1
+ - Value: 0x2
+ - Value: 0x0
+ - AbbrCode: 0x2
+ Values:
+ - Value: 0xF
+ - Value: 0x13
+ - Value: 0x1000
+ - Value: 0x1050
+ - AbbrCode: 0x0
+ debug_line:
+ - Length: 68
+ Version: 2
+ PrologueLength: 36
+ MinInstLength: 1
+ DefaultIsStmt: 1
+ LineBase: 251
+ LineRange: 14
+ OpcodeBase: 13
+ StandardOpcodeLengths: [ 0, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 1 ]
+ IncludeDirs:
+ - '/tmp'
+ Files:
+ - Name: main.cpp
+ DirIdx: 1
+ ModTime: 0
+ Length: 0
+ Opcodes:
+ - Opcode: DW_LNS_extended_op
+ ExtLen: 9
+ SubOpcode: DW_LNE_set_address
+ Data: 4096
+ - Opcode: DW_LNS_advance_line
+ SData: 9
+ Data: 0
+ - Opcode: DW_LNS_copy
+ Data: 0
+ - Opcode: DW_LNS_advance_pc
+ Data: 256
+ - Opcode: DW_LNS_advance_line
+ SData: 1
+ Data: 0
+ - Opcode: DW_LNS_copy
+ Data: 0
+ - Opcode: DW_LNS_advance_pc
+ Data: 256
+ - Opcode: DW_LNS_extended_op
+ ExtLen: 1
+ SubOpcode: DW_LNE_end_sequence
+ Data: 0
+ )";
+ auto ErrOrSections = DWARFYAML::emitDebugSections(yamldata);
+ ASSERT_THAT_EXPECTED(ErrOrSections, Succeeded());
+ std::unique_ptr<DWARFContext> DwarfContext =
+ DWARFContext::create(*ErrOrSections, 8);
+ ASSERT_TRUE(DwarfContext.get() != nullptr);
+ std::string errors;
+ raw_string_ostream OS(errors);
+ GsymCreator GC;
+ DwarfTransformer DT(*DwarfContext, GC);
+ const uint32_t ThreadCount = 1;
+ ASSERT_THAT_ERROR(DT.convert(ThreadCount, &OS), Succeeded());
+ ASSERT_THAT_ERROR(GC.finalize(OS), Succeeded());
+ OS.flush();
+ SmallString<512> Str;
+ raw_svector_ostream OutStrm(Str);
+ const auto ByteOrder = llvm::endianness::native;
+ FileWriter FW(OutStrm, ByteOrder);
+ ASSERT_THAT_ERROR(GC.encode(FW), Succeeded());
+ Expected<GsymReader> GR = GsymReader::copyBuffer(OutStrm.str());
+ ASSERT_THAT_EXPECTED(GR, Succeeded());
+ // There should be one function in our GSYM.
+ EXPECT_EQ(GR->getNumAddresses(), 1u);
+ // Verify "foo" is present and has a line table and no inline info.
+ auto ExpFI = GR->getFunctionInfo(0x1000);
+ ASSERT_THAT_EXPECTED(ExpFI, Succeeded());
+ ASSERT_EQ(ExpFI->Range, AddressRange(0x1000, 0x1050));
+ EXPECT_TRUE(ExpFI->OptLineTable.has_value());
+ EXPECT_FALSE(ExpFI->Inline.has_value());
+ StringRef FuncName = GR->getString(ExpFI->Name);
+ EXPECT_EQ(FuncName, "foo");
+
+ // Make sure we don't see spurious errors in the output:
+ EXPECT_TRUE(errors.find("error:") == std::string::npos);
+}
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