From 33845aa8c489e52e6287c75356daa8dd04b87350 Mon Sep 17 00:00:00 2001 From: Rafael Espindola Date: Wed, 26 Mar 2014 04:48:47 +0000 Subject: Prevent alias from pointing to weak aliases. 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. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204781 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Target/PowerPC/PPCAsmPrinter.cpp | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'lib/Target/PowerPC/PPCAsmPrinter.cpp') diff --git a/lib/Target/PowerPC/PPCAsmPrinter.cpp b/lib/Target/PowerPC/PPCAsmPrinter.cpp index daf90c86ef..9ce8ea911c 100644 --- a/lib/Target/PowerPC/PPCAsmPrinter.cpp +++ b/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