[PATCH] D81988: [ELF] Fix a dyn_cast<Defined>(nullptr) crash if a local symbol appears in InputFile::symbols
Fangrui Song via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Wed Jun 17 09:40:50 PDT 2020
MaskRay updated this revision to Diff 271387.
MaskRay marked an inline comment as done.
MaskRay added a comment.
Add comment to code. Improve test.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D81988/new/
https://reviews.llvm.org/D81988
Files:
lld/ELF/InputSection.cpp
lld/test/ELF/invalid/broken-symtab-duplicate-symbol.test
Index: lld/test/ELF/invalid/broken-symtab-duplicate-symbol.test
===================================================================
--- /dev/null
+++ lld/test/ELF/invalid/broken-symtab-duplicate-symbol.test
@@ -0,0 +1,28 @@
+# REQUIRES: x86
+## The ELF spec says all symbols with STB_LOCAL binding precede the weak and #
+## global symbols. Out-of-order local symbols are represented by null entries in
+## InputFile::symbols. Test that we don't crash.
+
+# RUN: yaml2obj %s -o %t.o
+# RUN: not ld.lld %t.o %t.o -o /dev/null 2>&1 | FileCheck %s
+# CHECK: error: duplicate symbol: _start
+# CHECK-NEXT: >>> defined at {{.*}}.o:(.text+0x0)
+# CHECK-NEXT: >>> defined at {{.*}}.o:(.text+0x0)
+
+!ELF
+FileHeader:
+ Class: ELFCLASS64
+ Data: ELFDATA2LSB
+ Type: ET_REL
+ Machine: EM_X86_64
+Sections:
+ - Type: SHT_PROGBITS
+ Name: .text
+ Flags: [ SHF_ALLOC, SHF_EXECINSTR ]
+Symbols:
+ - Name: _start
+ Section: .text
+ Binding: STB_GLOBAL
+ - Name: local
+ Section: .text
+ Binding: STB_LOCAL
Index: lld/ELF/InputSection.cpp
===================================================================
--- lld/ELF/InputSection.cpp
+++ lld/ELF/InputSection.cpp
@@ -345,9 +345,10 @@
if (!file->archiveName.empty())
archive = " in archive " + file->archiveName;
- // Find a symbol that encloses a given location.
+ // Find a symbol that encloses a given location. An out-of-order STB_LOCAL
+ // symbol is represented by a null entry.
for (Symbol *b : file->getSymbols())
- if (auto *d = dyn_cast<Defined>(b))
+ if (auto *d = dyn_cast_or_null<Defined>(b))
if (d->section == this && d->value <= off && off < d->value + d->size)
return filename + ":(" + toString(*d) + ")" + archive;
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