The interceptors had code that after macro expansion ended up looking like
extern "C" void memalign()
__attribute__((weak, alias("__interceptor_memalign")));
extern "C" void __interceptor_memalign() {}
extern "C" void __interceptor___libc_memalign()
__attribute__((alias("memalign")));
That is,
* __interceptor_memalign is a function
* memalign is a weak alias to __interceptor_memalign
* __interceptor___libc_memalign is an alias to memalign
Both gcc and clang produce assembly that look like
__interceptor_memalign:
...
.weak memalign
memalign = __interceptor_memalign
.globl __interceptor___libc_memalign
__interceptor___libc_memalign = memalign
What it means in the end is that we have 3 symbols pointing to the
same position in the file, one of which is weak:
8: 0000000000000000 1 FUNC GLOBAL DEFAULT 1
__interceptor_memalign
9: 0000000000000000 1 FUNC WEAK DEFAULT 1 memalign
10: 0000000000000000 1 FUNC GLOBAL DEFAULT 1
__interceptor___libc_memalign
In particular, note that __interceptor___libc_memalign will always
point to __interceptor_memalign, even if we do link in a strong symbol
for memalign. In fact, the above code produces exactly the same binary
as
extern "C" void memalign()
__attribute__((weak, alias("__interceptor_memalign")));
extern "C" void __interceptor_memalign() {}
extern "C" void __interceptor___libc_memalign()
__attribute__((alias("__interceptor_memalign")));
If nothing else, this patch makes it more obvious what is going on.
llvm-svn: 204823
The main difference between __va_start and __builtin_va_start is that
the address of the va_list has already been taken, and the va_list is
always a char*.
__va_end and __va_arg are not needed.
llvm-svn: 204821
parseDirectiveWord is a generic function that parses an expression which
means there's no need for it to have such an specific name. Renaming it to
parseDataDirective so that it can also be used to handle .dword directives[1].
[1]To be added in a follow up commit.
No functional changes.
llvm-svn: 204818
The '.set mips64' directive enables the feature Mips:FeatureMips64
from assembly. Note that it doesn't modify the ELF header as opposed
to the use of -mips64 from the command-line. The reason for this
is that we want to be as compatible as possible with existing assemblers
like GAS.
llvm-svn: 204817
The '.set mips64r2' directive enables the feature Mips:FeatureMips64r2
from assembly. Note that it doesn't modify the ELF header as opposed
to the use of -mips64r2 from the command-line. The reason for this
is that we want to be as compatible as possible with existing assemblers
like GAS.
llvm-svn: 204815
We've already got versions without the barriers, so this just adds IR-level
support for generating the new v8 ones.
rdar://problem/16227836
llvm-svn: 204813
Given that we support multiple directives that enable a particular feature
(e.g. '.set mips16'), it's best to hoist that code into a new function
so that we don't repeat the same pattern w.r.t parsing and handling error cases.
No functional changes.
llvm-svn: 204811
After some discussion on IRC, emitting a call to the library function seems
like a better default, since it will move from a compiler internal error to
a linker error, that the user can work around until LLVM is fixed.
I'm also adding a note on the responsibility of the user to confirm that
the cache was cleared on platforms where nothing is done.
llvm-svn: 204806
The directive '.option pic2' enables PIC from assembly source.
At the moment none of the macros/directives check the PIC bit
but that's going to be fixed relatively soon. For example, the
expansion of macros like 'la' depend on the relocation model.
llvm-svn: 204803
Implementing the LLVM part of the call to __builtin___clear_cache
which translates into an intrinsic @llvm.clear_cache and is lowered
by each target, either to a call to __clear_cache or nothing at all
incase the caches are unified.
Updating LangRef and adding some tests for the implemented architectures.
Other archs will have to implement the method in case this builtin
has to be compiled for it, since the default behaviour is to bail
unimplemented.
A Clang patch is required for the builtin to be lowered into the
llvm intrinsic. This will be done next.
llvm-svn: 204802
With VSX there is a real vector select instruction, and so we should use it.
Note that VSELECT will still scalarize for v2f64 because the corresponding
SetCC result type (v2i64) is not currently a legal type.
llvm-svn: 204801
These are aliases of t4-t7 and are provided for compatibility with both the
original ABI documentation (using t4-t7) and GNU As (using t0-t3)
llvm-svn: 204797
Summary: Added test cases for O32 and N32 on MIPS64.
Reviewers: matheusalmeida
Reviewed By: matheusalmeida
Differential Revision: http://llvm-reviews.chandlerc.com/D3175
llvm-svn: 204796
This reveals a small mistake in mips-register-names.s ($sp is tested twice and
$s8 is not tested) which will be fixed in a follow-up commit.
llvm-svn: 204792
This reverts commit r204781.
I will follow up to with msan folks to see what is what they
were trying to do with aliases to weak aliases.
llvm-svn: 204784
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: 204781
Summary:
This allows them to be used without -cc1 the same way as -I and -isystem.
Renamed the options to --system-header-prefix=/--no-system-header-prefix to avoid interference with -isystem and make the intent of the option cleaner.
Reviewers: rsmith
Reviewed By: rsmith
CC: cfe-commits
Differential Revision: http://llvm-reviews.chandlerc.com/D3185
llvm-svn: 204775
Reid Kleckner