From 0a70f9b3b9b4a8cb92f187ea0563c1a2ac784e6e Mon Sep 17 00:00:00 2001 From: Rafael Espindola Date: Thu, 20 Mar 2014 02:12:01 +0000 Subject: Look through variables when computing relocations. Given bar = foo + 4 .long bar MC would eat the 4. GNU as includes it in the relocation. The rule seems to be that a variable that defines a symbol is used in the relocation and one that does not define a symbol is evaluated and the result included in the relocation. Fixing this unfortunately required some other changes: * Since the variable is now evaluated, it would prevent the ELF writer from noticing the weakref marker the elf streamer uses. This patch then replaces that with a VariantKind in MCSymbolRefExpr. * Using VariantKind then requires us to look past other VariantKind to see .weakref bar,foo call bar@PLT doing this also fixes zed = foo +2 call zed@PLT so that is a good thing. * Looking past VariantKind means that the relocation selection has to use the fixup instead of the target. This is a reboot of the previous fixes for MC. I will watch the sanitizer buildbot and wait for a build before adding back the previous fixes. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204294 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/MC/MCELFStreamer.cpp | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'lib/MC/MCELFStreamer.cpp') diff --git a/lib/MC/MCELFStreamer.cpp b/lib/MC/MCELFStreamer.cpp index 5f6a889769..d07ef9e698 100644 --- a/lib/MC/MCELFStreamer.cpp +++ b/lib/MC/MCELFStreamer.cpp @@ -99,9 +99,8 @@ void MCELFStreamer::ChangeSection(const MCSection *Section, void MCELFStreamer::EmitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol) { getAssembler().getOrCreateSymbolData(*Symbol); - MCSymbolData &AliasSD = getAssembler().getOrCreateSymbolData(*Alias); - AliasSD.setFlags(AliasSD.getFlags() | ELF_Other_Weakref); - const MCExpr *Value = MCSymbolRefExpr::Create(Symbol, getContext()); + const MCExpr *Value = MCSymbolRefExpr::Create( + Symbol, MCSymbolRefExpr::VK_WEAKREF, getContext()); Alias->setVariableValue(Value); } -- cgit v1.2.3