[lld] r369271 - [ELF] Simplify processRelocAux and allow a corner-case error

[Fangrui Song via llvm-commits]

Author: maskray
Date: Mon Aug 19 08:52:29 2019
New Revision: 369271

URL: http://llvm.org/viewvc/llvm-project?rev=369271&view=rev
Log:
[ELF] Simplify processRelocAux and allow a corner-case error

After D66007/r369262, if the control flow reaches `if (sym.isUndefined())`, we know:

* The relocation is not a link-time constant => symbol is preemptable => Undefined or SharedSymbol
* Not an undef weak.
* -no-pie.
* The symbol type is neither STT_OBJECT nor STT_FUNC.

ld.lld --export-dynamic --unresolved-symbols=ignore-all %t.o can satisfy
these conditions. Delete the isUndefined() test so that we error
`symbol '...' has no type`, because we don't know the type to make the
decision to create copy relocation/canonical PLT.

Modified:
    lld/trunk/ELF/Relocations.cpp
    lld/trunk/test/ELF/x86-64-dyn-rel-error.s

Modified: lld/trunk/ELF/Relocations.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Relocations.cpp?rev=369271&r1=369270&r2=369271&view=diff
==============================================================================
--- lld/trunk/ELF/Relocations.cpp (original)
+++ lld/trunk/ELF/Relocations.cpp Mon Aug 19 08:52:29 2019
@@ -1077,10 +1077,6 @@ static void processRelocAux(InputSection
     return;
   }
 
-  // If the symbol is undefined we already reported any relevant errors.
-  if (sym.isUndefined())
-    return;
-
   errorOrWarn("symbol '" + toString(sym) + "' has no type" +
               getLocation(sec, sym, offset));
 }

Modified: lld/trunk/test/ELF/x86-64-dyn-rel-error.s
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/x86-64-dyn-rel-error.s?rev=369271&r1=369270&r2=369271&view=diff
==============================================================================
--- lld/trunk/test/ELF/x86-64-dyn-rel-error.s (original)
+++ lld/trunk/test/ELF/x86-64-dyn-rel-error.s Mon Aug 19 08:52:29 2019
@@ -11,6 +11,7 @@ _start:
 
 // CHECK: relocation R_X86_64_32 cannot be used against symbol zed; recompile with -fPIC
 
-// RUN: ld.lld --noinhibit-exec %t.o %t2.so -o %t 2>&1 | FileCheck --check-prefix=WARN %s
+// RUN: ld.lld --noinhibit-exec %t.o %t2.so -o /dev/null 2>&1 | FileCheck --check-prefix=WARN %s
+// RUN: not ld.lld --export-dynamic --unresolved-symbols=ignore-all %t.o -o /dev/null 2>&1 | FileCheck --check-prefix=WARN %s
 
 // WARN: symbol 'zed' has no type