From 24a669d225f9cacf1cd3846e333f9690a06d1e1c Mon Sep 17 00:00:00 2001 From: Rafael Espindola Date: Thu, 27 Mar 2014 15:26:56 +0000 Subject: Prevent alias from pointing to weak aliases. This adds back r204781. Original message: Aliases are just another name for a position in a file. As such, the regular symbol resolutions are not applied. For example, given define void @my_func() { ret void } @my_alias = alias weak void ()* @my_func @my_alias2 = alias void ()* @my_alias We produce without this patch: .weak my_alias my_alias = my_func .globl my_alias2 my_alias2 = my_alias That is, in the resulting ELF file my_alias, my_func and my_alias are just 3 names pointing to offset 0 of .text. That is *not* the semantics of IR linking. For example, linking in a @my_alias = alias void ()* @other_func would require the strong my_alias to override the weak one and my_alias2 would end up pointing to other_func. There is no way to represent that with aliases being just another name, so the best solution seems to be to just disallow it, converting a miscompile into an error. llvm-svn: 204934 --- llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp') diff --git a/llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp b/llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp index daf90c86ef9..9ce8ea911cf 100644 --- a/llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp +++ b/llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp @@ -381,8 +381,8 @@ void PPCAsmPrinter::EmitInstruction(const MachineInstr *MI) { if (MO.isGlobal()) { const GlobalValue *GValue = MO.getGlobal(); const GlobalAlias *GAlias = dyn_cast(GValue); - const GlobalValue *RealGValue = GAlias ? - GAlias->resolveAliasedGlobal(false) : GValue; + const GlobalValue *RealGValue = + GAlias ? GAlias->getAliasedGlobal() : GValue; MOSymbol = getSymbol(RealGValue); const GlobalVariable *GVar = dyn_cast(RealGValue); IsExternal = GVar && !GVar->hasInitializer(); @@ -428,8 +428,8 @@ void PPCAsmPrinter::EmitInstruction(const MachineInstr *MI) { else if (MO.isGlobal()) { const GlobalValue *GValue = MO.getGlobal(); const GlobalAlias *GAlias = dyn_cast(GValue); - const GlobalValue *RealGValue = GAlias ? - GAlias->resolveAliasedGlobal(false) : GValue; + const GlobalValue *RealGValue = + GAlias ? GAlias->getAliasedGlobal() : GValue; MOSymbol = getSymbol(RealGValue); const GlobalVariable *GVar = dyn_cast(RealGValue); @@ -463,8 +463,8 @@ void PPCAsmPrinter::EmitInstruction(const MachineInstr *MI) { if (MO.isGlobal()) { const GlobalValue *GValue = MO.getGlobal(); const GlobalAlias *GAlias = dyn_cast(GValue); - const GlobalValue *RealGValue = GAlias ? - GAlias->resolveAliasedGlobal(false) : GValue; + const GlobalValue *RealGValue = + GAlias ? GAlias->getAliasedGlobal() : GValue; MOSymbol = getSymbol(RealGValue); const GlobalVariable *GVar = dyn_cast(RealGValue); IsExternal = GVar && !GVar->hasInitializer(); -- cgit v1.2.3