llvm-6502/lib/Transforms
Rafael Espindola f165cf7ce8 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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204934 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-27 15:26:56 +00:00
..
Hello [C++11] Add 'override' keyword to virtual methods that override their base class. 2014-03-05 09:10:37 +00:00
InstCombine InstCombine: merge constants in both operands of icmp. 2014-03-27 11:16:05 +00:00
Instrumentation Prevent alias from pointing to weak aliases. 2014-03-27 15:26:56 +00:00
IPO Revert r204076 for now - it caused significant regressions in a number of 2014-03-23 04:22:31 +00:00
ObjCARC Fix use_iterator crash in ObjCArc from r203364 2014-03-18 22:32:43 +00:00
Scalar Treat lifetime.start'd memory like we treat freshly alloca'd memory. Patch by Björn Steinbrink! 2014-03-26 23:45:15 +00:00
Utils CloneFunction: Clone all attributes, including the CC 2014-03-26 22:26:35 +00:00
Vectorize SLP vectorizer: Don't hoist vector extracts of phis. 2014-03-25 02:18:47 +00:00
CMakeLists.txt Extracted ObjCARC.cpp into its own library libLLVMObjCARCOpts in preparation for refactoring the ARC Optimizer. 2013-01-28 01:35:51 +00:00
LLVMBuild.txt Extracted ObjCARC.cpp into its own library libLLVMObjCARCOpts in preparation for refactoring the ARC Optimizer. 2013-01-28 01:35:51 +00:00
Makefile Extracted ObjCARC.cpp into its own library libLLVMObjCARCOpts in preparation for refactoring the ARC Optimizer. 2013-01-28 01:35:51 +00:00