For a default visibility external linkage definition, dso_local is set for ELF
-fno-pic/-fpie and COFF and Mach-O. Since default clang -cc1 for ELF is similar
to -fpic ("PIC Level" is not set), this nuance causes unneeded binary format differences.
To make emitted IR similar, ELF -cc1 -fpic will default to -fno-semantic-interposition,
which sets dso_local for default visibility external linkage definitions.
To make this flip smooth and enable future (dso_local as definition default),
this patch replaces (function) `define ` with `define{{.*}} `,
(variable/constant/alias) `= ` with `={{.*}} `, or inserts appropriate `{{.*}} `.
We have option -mabi=ieeelongdouble to set current long double to
IEEEquad semantics. Like what GCC does, we need to define
__LONG_DOUBLE_IEEE128__ macro in this case, and __LONG_DOUBLE_IBM128__
if using PPCDoubleDouble.
Reviewed By: steven.zhang
Differential Revision: https://reviews.llvm.org/D90208
Summary:
Clang -fpic defaults to -fno-semantic-interposition (GCC -fpic defaults
to -fsemantic-interposition).
Users need to specify -fsemantic-interposition to get semantic
interposition behavior.
Semantic interposition is currently a best-effort feature. There may
still be some cases where it is not handled well.
Reviewers: peter.smith, rnk, serge-sans-paille, sfertile, jfb, jdoerfert
Subscribers: dschuff, jyknight, dylanmckay, nemanjai, jvesely, kbarton, fedor.sergeev, asb, rbar, johnrusso, simoncook, sabuasal, niosHD, jrtc27, zzheng, edward-jones, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, arphaman, PkmX, jocewei, jsji, Jim, lenary, s.egerton, pzheng, sameer.abuasal, apazos, luismarques, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D73865
gcc PowerPC supports 3 representations of long double:
* -mlong-double-64
long double has the same representation of double but is mangled as `e`.
In clang, this is the default on AIX, FreeBSD and Linux musl.
* -mlong-double-128
2 possible 128-bit floating point representations:
+ -mabi=ibmlongdouble
IBM extended double format. Mangled as `g`
In clang, this is the default on Linux glibc.
+ -mabi=ieeelongdouble
IEEE 754 quadruple-precision format. Mangled as `u9__ieee128` (`U10__float128` before gcc 8.2)
This is currently unavailable.
This patch adds -mabi=ibmlongdouble and -mabi=ieeelongdouble, and thus
makes the IEEE 754 quadruple-precision long double available for
languages supported by clang.
Reviewed By: hfinkel
Differential Revision: https://reviews.llvm.org/D64283
llvm-svn: 366044
This patch makes the driver option -mlong-double-128 available for X86
and PowerPC. The CC1 option -mlong-double-128 is available on all targets
for users to test on unsupported targets.
On PowerPC, -mlong-double-128 uses the IBM extended double format
because we don't support -mabi=ieeelongdouble yet (D64283).
Reviewed By: rnk
Differential Revision: https://reviews.llvm.org/D64277
llvm-svn: 365866
-mlong-double-64 is supported on some ports of gcc (i386, x86_64, and ppc{32,64}).
On many other targets, there will be an error:
error: unrecognized command line option '-mlong-double-64'
This patch makes the driver option -mlong-double-64 available for x86
and ppc. The CC1 option -mlong-double-64 is available on all targets for
users to test on unsupported targets.
LongDoubleSize is added as a VALUE_LANGOPT so that the option can be
shared with -mlong-double-128 when we support it in clang.
Also, make powerpc*-linux-musl default to use 64-bit long double. It is
currently the only supported ABI on musl and is also how people
configure powerpc*-linux-musl-gcc.
Reviewed By: rnk
Differential Revision: https://reviews.llvm.org/D64067
llvm-svn: 365412
Fangrui Song