[PATCH] D71679: [LLD] [COFF] Fix reporting duplicate errors for absolute symbols

[Martin Storsjö via Phabricator via llvm-commits]

mstorsjo created this revision.
mstorsjo added reviewers: ruiu, rnk.
Herald added a project: LLVM.

Previously this caused crashes in the reportDuplicate method.

A DefinedAbsolute doesn't have any InputFile attached to it, so we can't report the file for the original symbol.

We could add an InputFile argument to SymbolTable::addAbsolute only for the sake of error reporting, but even then it'd be assymetrical, only pointing out the file containing the new conflicting definition, not the original one.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D71679

Files:
  lld/COFF/SymbolTable.cpp
  lld/test/COFF/duplicate-absolute.s


Index: lld/test/COFF/duplicate-absolute.s
===================================================================
--- /dev/null
+++ lld/test/COFF/duplicate-absolute.s
@@ -0,0 +1,14 @@
+// REQUIRES: x86
+// RUN: llvm-mc -triple x86_64-windows-msvc -filetype obj -o %t.obj %s
+// RUN: echo -e ".globl myabsolute\nmyabsolute = 0" > %t.dupl.s
+// RUN: llvm-mc -triple x86_64-windows-msvc -filetype obj -o %t.dupl.obj %t.dupl.s
+// RUN: not lld-link /out:%t.exe %t.obj %t.dupl.obj 2>&1 | FileCheck %s
+
+// CHECK: error: duplicate symbol: myabsolute
+
+.globl myabsolute
+myabsolute = 0
+
+.globl entry
+entry:
+    ret
Index: lld/COFF/SymbolTable.cpp
===================================================================
--- lld/COFF/SymbolTable.cpp
+++ lld/COFF/SymbolTable.cpp
@@ -545,6 +545,8 @@
 
 static std::string getSourceLocation(InputFile *file, SectionChunk *sc,
                                      uint32_t offset, StringRef name) {
+  if (!file)
+    return "";
   if (auto *o = dyn_cast<ObjFile>(file))
     return getSourceLocationObj(o, sc, offset, name);
   if (auto *b = dyn_cast<BitcodeFile>(file))
@@ -566,7 +568,7 @@
   llvm::raw_string_ostream os(msg);
   os << "duplicate symbol: " << toString(*existing);
 
-  DefinedRegular *d = cast<DefinedRegular>(existing);
+  DefinedRegular *d = dyn_cast<DefinedRegular>(existing);
   if (d && isa<ObjFile>(d->getFile())) {
     os << getSourceLocation(d->getFile(), d->getChunk(), d->getValue(),
                             existing->getName());


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