Don't populate the symbol table with symbols that don't belong to a s…

…ection with the flag SHF_ALLOC

When populating the symbol table for an ELF object file, don't insert any symbols that come from ELF sections which don't have runtime allocated memory (typically debugging symbols).

Reviewed By: dblaikie

Differential Revision: https://reviews.llvm.org/D133795

llvm/lib/DebugInfo/Symbolize/SymbolizableObjectFile.cpp

@@ -168,6 +168,11 @@ Error SymbolizableObjectFile::addSymbol(const SymbolRef &Symbol,
     return SymbolTypeOrErr.takeError();
   SymbolRef::Type SymbolType = *SymbolTypeOrErr;
   if (Obj.isELF()) {
+    // Ignore any symbols coming from sections that don't have runtime
+    // allocated memory.
+    if ((elf_section_iterator(*Sec)->getFlags() & ELF::SHF_ALLOC) == 0)
+      return Error::success();
+
     // Allow function and data symbols. Additionally allow STT_NONE, which are
     // common for functions defined in assembly.
     uint8_t Type = ELFSymbolRef(Symbol).getELFType();

llvm/test/DebugInfo/Symbolize/ELF/symtab-file2.yaml

@@ -73,3 +73,39 @@ Symbols:
     Index:   SHN_ABS
   - Name:    local
     Section: .text
+
+# RUN: yaml2obj --docnum=3 %s -o %t3
+# RUN: llvm-symbolizer --obj=%t3 'DATA 0x1001' 2>&1 | FileCheck %s --check-prefix=CHECK3
+
+# CHECK3:      code
+# CHECK3-NEXT: 4096 2
+# CHECK3-NEXT: ??:?
+# CHECK3-EMPTY:
+
+--- !ELF
+FileHeader:
+  Class:   ELFCLASS64
+  Data:    ELFDATA2LSB
+  Type:    ET_DYN
+  Machine: EM_X86_64
+Sections:
+  - Name:    .text
+    Type:    SHT_PROGBITS
+    Flags:   [ SHF_ALLOC, SHF_EXECINSTR ]
+    Address: 0x1000
+    Size:    1
+  - Name:    .debug
+    Type:    SHT_PROGBITS
+    Address: 0x0000
+    Size:    0xFFFF
+Symbols:
+  - Name:    debug
+    Section: .debug
+    Binding: STB_WEAK
+    Value:   0x1001
+    Size:    0
+  - Name:    code
+    Section: .text
+    Binding: STB_WEAK
+    Value:   0x1000
+    Size:    2