24a669d225
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
37 lines
827 B
LLVM
37 lines
827 B
LLVM
; RUN: llvm-as < %s | llvm-dis > %t1.ll
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; RUN: llvm-as %t1.ll -o - | llvm-dis > %t2.ll
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; RUN: diff %t1.ll %t2.ll
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@llvm.used = appending global [1 x i8*] [i8* bitcast (i32* @foo1 to i8*)], section "llvm.metadata"
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@bar = global i32 0
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@foo1 = alias i32* @bar
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@foo2 = alias i32* @bar
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@foo3 = alias i32* @foo2
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%FunTy = type i32()
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define i32 @foo_f() {
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ret i32 0
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}
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@bar_f = alias weak_odr %FunTy* @foo_f
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@bar_ff = alias i32()* @bar_f
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@bar_i = alias internal i32* @bar
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@A = alias bitcast (i32* @bar to i64*)
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define i32 @test() {
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entry:
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%tmp = load i32* @foo1
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%tmp1 = load i32* @foo2
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%tmp0 = load i32* @bar_i
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%tmp2 = call i32 @foo_f()
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%tmp3 = add i32 %tmp, %tmp2
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%tmp4 = call %FunTy* @bar_f()
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%tmp5 = add i32 %tmp3, %tmp4
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%tmp6 = add i32 %tmp1, %tmp5
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%tmp7 = add i32 %tmp6, %tmp0
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ret i32 %tmp7
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}
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