Sometimes a collection of multilibs has a gap in it, where a set of
driver command-line options can't work with any of the available
libraries.
For example, the Arm MVE extension requires special startup code (you
need to initialize FPSCR.LTPSIZE), and also benefits greatly from
-mfloat-abi=hard. So a multilib provider might build a library for
systems without MVE, and another for MVE with -mfloat-abi=hard,
anticipating that that's what most MVE users would want. But then if a
user compiles for MVE _without_ -mfloat-abi=hard, thhey can't use either
of those libraries – one has an ABI mismatch, and the other will fail to
set up LTPSIZE.
In that situation, it's useful to include a multilib.yaml entry for the
unworkable intermediate situation, and have it map to a fatal error
message rather than a set of actual libraries. Then the user gets a
build failure with a sensible explanation, instead of selecting an
unworkable library and silently generating bad output. The new
regression test demonstrates this case.
This patch introduces extra syntax into multilib.yaml, so that a record
in the `Variants` list can omit the `Dir` key, and in its place, provide
a `FatalError` key. Then, if that variant is selected, the error message
is emitted as a clang diagnostic, and multilib selection fails.
In order to emit the error message in `MultilibSet::select`, I had to
pass a `Driver &` to that function, which involved plumbing one through
to every call site, and in the unit tests, constructing one specially.
This will enable layering multilibs on top of each other.
For example a multilib containing only a no-exceptions libc++ could be
layered on top of a multilib containing C libs. This avoids the need
to duplicate the C library for every libc++ variant.
This change doesn't expose the functionality externally, it only opens
the functionality up to be potentially used by ToolChain classes.
Differential Revision: https://reviews.llvm.org/D143059
This new representation means that a valid command line option may
potentially be used directly as a multilib flag without any translation.
To indicate that a flag is required not to be present, its first
character is replaced with '!', which is intended for consistency with
the logical not operator in many programming languages.
Reviewed By: simon_tatham
Differential Revision: https://reviews.llvm.org/D151438
Decouple the interface of the MultilibBuilder flag method from how flags
are stored internally. Likewise change the addMultilibFlag function.
Currently a multilib flag like "-fexceptions" means a multilib is
*incompatible* with the -fexceptions command line option, which is
counter-intuitive. This change is a step towards changing this scheme.
Differential Revision: https://reviews.llvm.org/D151437
The compiler-rt library path can be either {resource_dir}/lib/{triple}
or {resource_dir}/lib/{OS}/{arch} depending on whether
LLVM_ENABLE_PER_TARGET_RUNTIME_DIR_default is ON or OFF.
Currently, the rpath added by -rtlib-add-rpath only adds
the latter. This patch checks both and adds the one that exists.
Reviewed by: Fangrui Song
Differential Revision: https://reviews.llvm.org/D146686
The new algorithm is:
1. Find all multilibs with flags that are a subset of the requested
flags.
2. If more than one multilib matches, choose the last.
In addition a new selection mechanism is permitted via an overload of
MultilibSet::select() for which multiple multilibs are returned.
This allows layering multilibs on top of each other.
Since multilibs are now ordered within a list, they no longer need a
Priority field.
The new algorithm is different to the old algorithm, but in practise
the old algorithm was always used in such a way that the effect is the
same.
The old algorithm was to find the set intersection of the requested
flags (with the first character of each removed) with each multilib's
flags (ditto), and for that intersection check whether the first
character matched. However, ignoring the first characters, the
requested flags were always a superset of all the multilibs flags.
Therefore the new algorithm can be used as a drop-in replacement.
The exception is Fuchsia, which needs adjusting slightly to set both
fexceptions and fno-exceptions flags.
Differential Revision: https://reviews.llvm.org/D142905
Add a clang part of OpenHarmony target
Related LLVM part: D138202
~~~
Huawei RRI, OS Lab
Reviewed By: DavidSpickett
Differential Revision: https://reviews.llvm.org/D145227
This change had tests that break whenever LLVM_ENABLE_LINKER_BUILD_ID is
set, as is the case in the Fuchsia target.
This reverts commits:
f81317a54586dbcef0c14cf512a0770e8ecaab3d
72474afa27570a0a1307f3260f0187b703aa6d84
Add a clang part of OpenHarmony target
Related LLVM part: D138202
~~~
Huawei RRI, OS Lab
Reviewed By: DavidSpickett
Differential Revision: https://reviews.llvm.org/D145227
