Commit Graph

16 Commits

Author SHA1 Message Date
Roman Lebedev 3dd5a298bf
[clang] Annotating C++'s `operator new` with more attributes
Summary:
Right now we annotate C++'s `operator new` with `noalias` attribute,
which very much is healthy for optimizations.

However as per [[ http://eel.is/c++draft/basic.stc.dynamic.allocation | `[basic.stc.dynamic.allocation]` ]],
there are more promises on global `operator new`, namely:
* non-`std::nothrow_t` `operator new` *never* returns `nullptr`
* If `std::align_val_t align` parameter is taken, the pointer will also be `align`-aligned
* ~~global `operator new`-returned pointer is `__STDCPP_DEFAULT_NEW_ALIGNMENT__`-aligned ~~ It's more caveated than that.

Supplying this information may not cause immediate landslide effects
on any specific benchmarks, but it for sure will be healthy for optimizer
in the sense that the IR will better reflect the guarantees provided in the source code.

The caveat is `-fno-assume-sane-operator-new`, which currently prevents emitting `noalias`
attribute, and is automatically passed by Sanitizers ([[ https://bugs.llvm.org/show_bug.cgi?id=16386 | PR16386 ]]) - should it also cover these attributes?
The problem is that the flag is back-end-specific, as seen in `test/Modules/explicit-build-flags.cpp`.
But while it is okay to add `noalias` metadata in backend, we really should be adding at least
the alignment metadata to the AST, since that allows us to perform sema checks on it.

Reviewers: erichkeane, rjmccall, jdoerfert, eugenis, rsmith

Reviewed By: rsmith

Subscribers: xbolva00, jrtc27, atanasyan, nlopes, cfe-commits

Tags: #llvm, #clang

Differential Revision: https://reviews.llvm.org/D73380
2020-02-26 01:37:17 +03:00
Gabor Buella d8f4991284 [NFC] - Partially revert 9c48c2f9c4 2019-12-12 12:46:17 +01:00
Gabor Buella 9c48c2f9c4 [NFC] - Typo fix in test/CodeGenCXX/runtime-dllstorage.cpp
Reviewed By: Jim

Differential Revision: https://reviews.llvm.org/D48921
2019-12-12 11:26:54 +01:00
Tim Northover a009a60a91 IR: print value numbers for unnamed function arguments
For consistency with normal instructions and clarity when reading IR,
it's best to print the %0, %1, ... names of function arguments in
definitions.

Also modifies the parser to accept IR in that form for obvious reasons.

llvm-svn: 367755
2019-08-03 14:28:34 +00:00
Reid Kleckner 1808c02c15 Re-land r359250, [COFF] Statically link certain runtime library functions
Reverts the revert of r359251, this time with fixed tests.

Differential Revision: https://reviews.llvm.org/D55229

llvm-svn: 359513
2019-04-29 23:05:47 +00:00
Reid Kleckner 1be5369a0c Revert [COFF] Statically link certain runtime library functions
This reverts r359250 (git commit 4730604bd3)

The newly added test should use -cc1 and -emit-llvm and there are other
test failures that need fixing.

llvm-svn: 359251
2019-04-25 23:30:41 +00:00
Reid Kleckner 4730604bd3 [COFF] Statically link certain runtime library functions
Statically link certain runtime library functions for MSVC/GNU Windows
environments. This is consistent with MSVC behavior.

Fixes LNK4286 and LNK4217 warnings from link.exe when linking the static
CRT:
  LINK : warning LNK4286: symbol '__std_terminate' defined in 'libvcruntime.lib(ehhelpers.obj)' is imported by 'ASAN_NOINST_TEST_OBJECTS.asan_noinst_test.cc.x86_64-calls.o'
  LINK : warning LNK4286: symbol '__std_terminate' defined in 'libvcruntime.lib(ehhelpers.obj)' is imported by 'ASAN_NOINST_TEST_OBJECTS.asan_test_main.cc.x86_64-calls.o'
  LINK : warning LNK4217: symbol '_CxxThrowException' defined in 'libvcruntime.lib(throw.obj)' is imported by 'ASAN_NOINST_TEST_OBJECTS.gtest-all.cc.x86_64-calls.o' in function '"int `public: static class UnitTest::GetInstance * __cdecl testing::UnitTest::GetInstance(void)'::`1'::dtor$5" (?dtor$5@?0??GetInstance@UnitTest@testing@@SAPEAV12@XZ@4HA)'

Reviewers: mstorsjo, efriedma, TomTan, compnerd, smeenai, mgrang

Subscribers: abdulras, theraven, smeenai, pcc, mehdi_amini, javed.absar, inglorion, kristof.beyls, dexonsmith, cfe-commits

Differential Revision: https://reviews.llvm.org/D55229

llvm-svn: 359250
2019-04-25 23:04:20 +00:00
Joel E. Denny 72c2783012 [FileCheck] Add -allow-deprecated-dag-overlap to failing clang tests
See https://reviews.llvm.org/D47106 for details.

Reviewed By: probinson

Differential Revision: https://reviews.llvm.org/D47172

llvm-svn: 336844
2018-07-11 20:26:20 +00:00
Rafael Espindola 3c9be62d24 Set dso_local for runtime function.
This is another case where there is special logic for adding dllimport
and so we cannot use setGVProperties.

llvm-svn: 328036
2018-03-20 20:27:30 +00:00
Reid Kleckner fb93154bf1 [MS] Don't escape MS C++ names with \01
It is not needed after LLVM r327734. Now it will be easier to copy-paste
IR symbol names from Clang.

llvm-svn: 327738
2018-03-16 20:36:49 +00:00
Rafael Espindola abdb322438 Set dso_local on tls init functions.
We copy the visibility, so copying the dso_local flag seems the
natural thing to do.

llvm-svn: 326961
2018-03-07 23:18:06 +00:00
Rafael Espindola 922f2aa9b2 Bring r325915 back.
The tests that failed on a windows host have been fixed.

Original message:

Start setting dso_local for COFF.

With this there are still some GVs where we don't set dso_local
because setGVProperties is never called. I intend to fix that in
followup commits. This is just the bare minimum to teach
shouldAssumeDSOLocal what it should do for COFF.

llvm-svn: 325940
2018-02-23 19:30:48 +00:00
Rafael Espindola 43ce3a3a4d Revert "Start setting dso_local for COFF."
This reverts commit r325915.

It will take some time to fix the failures on a windows host.

llvm-svn: 325929
2018-02-23 18:09:29 +00:00
Rafael Espindola 004d240b6a Start setting dso_local for COFF.
With this there are still some GVs where we don't set dso_local
because setGVProperties is never called. I intend to fix that in
followup commits. This is just the bare minimum to teach
shouldAssumeDSOLocal what it should do for COFF.

llvm-svn: 325915
2018-02-23 15:32:32 +00:00
Martell Malone b22e600484 CodeGenCXX: no default dllimport storage for mingw
GNU frontends don't have options like /MT, /MD
This fixes a few link error regressions with libc++ and libc++abi

Reviewers: rnk, mstorsjo, compnerd

Differential Revision: https://reviews.llvm.org/D33620

llvm-svn: 317398
2017-11-04 02:15:49 +00:00
Saleem Abdulrasool 6cb0744934 CodeGen: fix runtime function dll storage
Properly attribute DLL storage to runtime functions.  When generating the
runtime function, scan for an existing declaration which may provide an explicit
declaration (local storage) or a DLL import or export storage from the user.
Honour that if available.  Otherwise, if building with a local visibility of the
public or standard namespaces (-flto-visibility-public-std), give the symbols
local storage (it indicates a /MT[d] link, so static runtime).  Otherwise,
assume that the link is dynamic, and give the runtime function dllimport
storage.

This allows for implementations to get the correct storage as long as they are
properly declared, the user to override the import storage, and in case no
explicit storage is given, use of the import storage.

llvm-svn: 289776
2016-12-15 06:59:05 +00:00