According to D53384, the default was switched from -fno-PIC to -fPIC to
work around a -fsanitize=leak bug on big-endian.
This gratuitous difference between little-endian and big-endian is
undesired, and not acceptable on powerpc64-unknown-freebsd. If
-fsanitize=leak still has the problem, we should consider defaulting to
-fPIC/-fPIE only when -fsanitize=leak is specified (see SanitizerArgs::requiresPIE())
powerpc64-ibm-aix is unaffected: it still defaults to -fPIC.
powerpc64-linux-musl is unaffected (-fPIE since D39588): it still defaults to -fPIE.
Reviewed By: #powerpc, jhibbits
Differential Revision: https://reviews.llvm.org/D72363
Summary:
Every powerpc64le platform uses elfv2.
For powerpc64, the environments "elfv1" and "elfv2" were added for
FreeBSD ELFv1->ELFv2 migration in D61950. FreeBSD developers have
decided to use OS versions to select ABI, and no one is relying on the
environments.
Also use elfv2 on powerpc64-linux-musl.
Users can always use -mabi=elfv1 and -mabi=elfv2 to override the default
ABI.
Reviewed By: adalava
Differential Revision: https://reviews.llvm.org/D72352
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
Most of the PowerPC64 code generation already creates PIC access. This
changes to a full PIC default, similar to what GCC is doing.
Overall, a monolithic clang binary shrinks by 600KB (about 1%). This can
be a slight regression for TLS access and will use the TOC more
aggressively instead of synthesizing immediates. It is expected to be
performance neutral.
Differential Revision: https://reviews.llvm.org/D26564
llvm-svn: 289744
All of the ABIs we support are altivec style anyhow and so the option
doesn't make much sense with the modern ABIs. We could make this a more
noisy ignore, but it would break builds for projects that just pass
it along by default because of historical reasons.
llvm-svn: 241925
Support for the QPX vector instruction set, used on the IBM BG/Q supercomputer,
has recently been added to the LLVM PowerPC backend. This vector instruction
set requires some ABI modifications because the ABI on the BG/Q expects
<4 x double> vectors to be provided with 32-byte stack alignment, and to be
handled as native vector types (similar to how Altivec vectors are handled on
mainline PPC systems). I've named this ABI variant elfv1-qpx, have made this
the default ABI when QPX is supported, and have updated the ABI handling code
to provide QPX vectors with the correct stack alignment and associated
register-assignment logic.
llvm-svn: 231960
While Clang now supports both ELFv1 and ELFv2 ABIs, their use is currently
hard-coded via the target triple: powerpc64-linux is always ELFv1, while
powerpc64le-linux is always ELFv2.
These are of course the most common scenarios, but in principle it is
possible to support the ELFv2 ABI on big-endian or the ELFv1 ABI on
little-endian systems (and GCC does support that), and there are some
special use cases for that (e.g. certain Linux kernel versions could
only be built using ELFv1 on LE).
This patch implements the Clang side of supporting this, based on the
LLVM commit 214072. The command line options -mabi=elfv1 or -mabi=elfv2
select the desired ABI if present. (If not, Clang uses the same default
rules as now.)
Specifically, the patch implements the following changes based on the
presence of the -mabi= option:
In the driver:
- Pass the appropiate -target-abi flag to the back-end
- Select the correct dynamic loader version (/lib64/ld64.so.[12])
In the preprocessor:
- Define _CALL_ELF to the appropriate value (1 or 2)
In the compiler back-end:
- Select the correct ABI in TargetInfo.cpp
- Select the desired ABI for LLVM via feature (elfv1/elfv2)
llvm-svn: 214074
Fangrui Song