Commit Graph

45 Commits

Author SHA1 Message Date
Eli Friedman 62f3ef2b53 [CGCall] Annotate references with "align" attribute.
If we're going to assume references are dereferenceable, we should also
assume they're aligned: otherwise, we can't actually dereference them.

See also D80072.

Differential Revision: https://reviews.llvm.org/D80166
2020-05-19 20:21:30 -07:00
Erik Pilkington de98cf92e3 [CodeGen] Add an alignment attribute to all sret parameters
This fixes a miscompile when the parameter is actually underaligned.
rdar://58316406

Differential revision: https://reviews.llvm.org/D74183
2020-03-24 15:31:57 -04:00
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
Fangrui Song dbc96b518b Revert "[CodeGenModule] Assume dso_local for -fpic -fno-semantic-interposition"
This reverts commit 789a46f2d7.

Accidentally committed.
2020-02-03 10:09:39 -08:00
Fangrui Song 789a46f2d7 [CodeGenModule] Assume dso_local for -fpic -fno-semantic-interposition
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
2020-02-03 09:52:48 -08:00
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
Sean Fertile d900dd0c23 Revert "[CodeGenCXX] Treat 'this' as noalias in constructors"
This reverts commit https://reviews.llvm.org/rL344150 which causes
MachineOutliner related failures on the ppc64le multistage buildbot.

llvm-svn: 344526
2018-10-15 15:43:00 +00:00
Anton Bikineev cc7e74753a [CodeGenCXX] Treat 'this' as noalias in constructors
This is currently a clang extension and a resolution
of the defect report in the C++ Standard.

Differential Revision: https://reviews.llvm.org/D46441

llvm-svn: 344150
2018-10-10 16:14:51 +00:00
Charles Li fad02411e0 [Lit Test] Make tests C++11 compatible - nothrow destructors
In C++11, a destructor's implicit exception-spec is nothrow.
The IR for the destructor's invocation changed from invoke to call.

Differential Revision: https://reviews.llvm.org/D28425

llvm-svn: 291458
2017-01-09 18:24:16 +00:00
Richard Smith 351241c83e Replace Sema-level implementation of -fassume-sane-operator-new with a
CodeGen-level implementation. Instead of adding an attribute to clang's
FunctionDecl, add the IR attribute directly. This means a module built with
this flag is now compatible with code built without it and vice versa.

This change also results in the 'noalias' attribute no longer being added to
calls to operator new in the IR; it's now only added to the declaration. It
also fixes a bug where we failed to add the attribute to the 'nothrow' versions
(because we didn't implicitly declare them, there was no good time to inject a
fake attribute).

llvm-svn: 265728
2016-04-07 21:46:12 +00:00
John McCall 53dcf94d05 Don't crash when a reserved global placement operator new is paired
with a non-reserved operator delete in a new-expression.

llvm-svn: 248862
2015-09-29 23:55:17 +00:00
David Majnemer e40fe37c43 Use the reserved keyword spelling of 'typeof'
No functional change intended, just a drive-by cleanup.

llvm-svn: 243826
2015-08-01 05:31:56 +00:00
David Blaikie a953f2825b Update Clang tests to handle explicitly typed load changes in LLVM.
llvm-svn: 230795
2015-02-27 21:19:58 +00:00
David Blaikie 218b783192 Update Clang tests to handle explicitly typed gep changes in LLVM.
llvm-svn: 230783
2015-02-27 19:18:17 +00:00
Reid Kleckner 4c209c7e1f Add a comdat to __clang_call_terminate
llvm-svn: 228863
2015-02-11 18:50:13 +00:00
Hal Finkel a2347baaec Mark C++ reference parameters as dereferenceable
Because references must be initialized using some evaluated expression, they
must point to something, and a callee can assume the reference parameter is
dereferenceable. Taking advantage of a new attribute just added to LLVM, mark
them as such.

Because dereferenceability in addrspace(0) implies nonnull in the backend, we
don't need both attributes. However, we need to know the size of the object to
use the dereferenceable attribute, so for incomplete types we still emit only
nonnull.

llvm-svn: 213386
2014-07-18 15:52:10 +00:00
Nick Lewycky 9b46eb8112 Add 'nonnull' parameter or return attribute when producing an llvm pointer type in a function type where the C++ type is a reference. Update the tests.
llvm-svn: 209723
2014-05-28 09:56:42 +00:00
Stephen Lin 4362261b00 CHECK-LABEL-ify some code gen tests to improve diagnostic experience when tests fail.
llvm-svn: 188447
2013-08-15 06:47:53 +00:00
Bill Wendling 706469b453 Add more of the command line options as attribute flags.
These can be easily queried by the back-end.

llvm-svn: 176304
2013-02-28 22:49:57 +00:00
Bill Wendling 2386bb130c Reapply r176133 with testcase fixes.
llvm-svn: 176145
2013-02-27 00:06:04 +00:00
Anna Zaks 0f424b029b Revert "Add more attributes from the command line to functions."
This reverts commit 176009.

The commit is a likely cause of several buildbot failures.

llvm-svn: 176044
2013-02-25 19:51:03 +00:00
Bill Wendling 87869db5f5 Add more attributes from the command line to functions.
This is an ongoing process. Any command line option which a back-end cares about
should be added here.

llvm-svn: 176009
2013-02-25 07:15:16 +00:00
Bill Wendling e1c4a1babd Update to use references to attribute groups instead of listing the attributes on the call/invoke instructions.
llvm-svn: 175878
2013-02-22 09:10:20 +00:00
Bill Wendling c33fc4c004 Modify the tests to use attribute group references instead of listing the
function attributes.

llvm-svn: 175606
2013-02-20 07:22:19 +00:00
John McCall e142ad50f1 Call __cxa_begin_catch with the current exception before
calling std::terminate().  rdar://11904428

llvm-svn: 174940
2013-02-12 03:51:46 +00:00
John McCall 12cc42aa1b Destroy arrays and ARC fields when throwing out of ctors.
Previously we were only handling non-array fields of class type.

Testcases derived from a patch by WenHan Gu.

llvm-svn: 174146
2013-02-01 05:11:40 +00:00
John McCall b0433eeb2e During jump-scope checking, build an ExprWithCleanups immediately
into the enclosing scope;  this is a more accurate model but is
(I believe) unnecessary in my test case due to other flaws.
However, one of those flaws is now intentional:  blocks which
appear in return statements can be trivially observed to not
extend in lifetime past the return, and so we can allow a jump
past them.  Do the necessary magic in IR-generation to make
this work.

llvm-svn: 164589
2012-09-25 06:56:03 +00:00
John McCall d8d00be632 It turns out that implementing the rethrow-on-fallthrough
semantics of a ctor/dtor function-try-block catch handler
by pushing a normal cleanup is not just overkill but actually
actively wrong when the handler contains an explicit return
(which is only legal in a dtor).  Just emit the rethrow as
ordinary code at the fallthrough point.  Fixes PR13102.

llvm-svn: 158488
2012-06-15 05:27:05 +00:00
Eli Friedman b971d49765 Elide copy construction in new expressions. PR11757.
llvm-svn: 150738
2012-02-16 22:45:48 +00:00
John McCall f4beacd059 Whenever explicitly activating or deactivating a cleanup, we
need to provide a 'dominating IP' which is guaranteed to
dominate the (de)activation point but which cannot be avoided
along any execution path from the (de)activation point to
the push-point of the cleanup.  Using the entry block is
bad mojo.

llvm-svn: 144276
2011-11-10 10:43:54 +00:00
Eli Friedman cf9b1f6524 Rearrange code so that we pass the right pointer to delete[] when an exception is thrown constructing the array elements in an array new expression. Fixes PR10870.
llvm-svn: 139158
2011-09-06 18:53:03 +00:00
John McCall a8a39bc346 An initialization does not alias.
llvm-svn: 138624
2011-08-26 05:38:08 +00:00
John McCall 35e4f0cd0f The allocated exception slot does not alias anything; should fix self-host.
llvm-svn: 138615
2011-08-26 00:46:38 +00:00
John McCall 8e4c74bb7c Simplify EH control flow by observing that EH scopes form a simple
hierarchy of delegation, and that EH selector values are meaningful
function-wide (good thing, too, or inlining wouldn't work).
2,3d
1a
hierarchy of delegation and that EH selector values have the same
meaning everywhere in the function instead of being meaningful only
in the context of a specific selector.

This removes the need for routing edges through EH cleanups,
since a cleanup simply always branches to its enclosing scope.

llvm-svn: 137293
2011-08-11 02:22:43 +00:00
John McCall 9b382dde92 Convert Clang over to resuming from landing pads with llvm.eh.resume.
It's quite likely that this will explode, but I need to know how. :)

llvm-svn: 132269
2011-05-28 21:13:02 +00:00
John McCall 75f9498a7c The conditional needs to be pushed before the branch. Make the test less
trivial to check this.  Adjust for style.

llvm-svn: 127151
2011-03-07 03:12:35 +00:00
John McCall f7dcf320a7 An operator new with an empty exception specifier returns null on a bad
allocation and therefore requires a null-check.  We were doing that, but
we weren't treating the new-initializer as being conditionally executed,
which means it was possible to get ill-formed IR as in PR9298.

llvm-svn: 127147
2011-03-07 01:52:56 +00:00
Anders Carlsson 6774b1f1c1 Add -fcxx-exceptions to all tests that use C++ exceptions.
llvm-svn: 126599
2011-02-28 00:40:07 +00:00
John McCall 1b93f1ba9f Tame an assert; the scope depth of a jump destination does not
necessarily enclose the innermost normal cleanup depth, because
the top of the jump scope stack might be an EH cleanup or EH scope.
Fixes PR9303.

llvm-svn: 126472
2011-02-25 04:19:13 +00:00
John McCall 1bf5846abf Save a copy expression for non-trivial copy constructions of catch variables.
llvm-svn: 125661
2011-02-16 08:02:54 +00:00
John McCall f256eb54a2 Fix some obvious bugs in the conditional-cleanup code and then make the
dtor cleanup use it.

llvm-svn: 124309
2011-01-26 19:15:39 +00:00
John McCall 7f9c92a9a0 When emitting a new-expression inside a conditional expression,
the cleanup might not be dominated by the allocation code.
In this case, we have to store aside all the delete arguments
in case we need them later.  There's room for optimization here
in cases where we end up not actually needing the cleanup in
different branches (or being able to pop it after the
initialization code).

Also make sure we only call this operator delete along the path
where we actually allocated something.

Fixes rdar://problem/8439196.

llvm-svn: 114145
2010-09-17 00:50:28 +00:00
John McCall 824c2f537c Implement the EH cleanup to call 'operator delete' if a new-expression throws
(but not if destructors associated with the full-expression throw).

llvm-svn: 113836
2010-09-14 07:57:04 +00:00
Daniel Dunbar 8fbe78f6fc Update tests to use %clang_cc1 instead of 'clang-cc' or 'clang -cc1'.
- This is designed to make it obvious that %clang_cc1 is a "test variable"
   which is substituted. It is '%clang_cc1' instead of '%clang -cc1' because it
   can be useful to redefine what gets run as 'clang -cc1' (for example, to set
   a default target).

llvm-svn: 91446
2009-12-15 20:14:24 +00:00
Anders Carlsson afd1edb52e When an exception needs to be freed by calling __cxa_exception_free, make sure to stash away the exception pointer somewhere.
This fixes an "Instruction does not dominate all uses!" verification error when compiling TableGen.

llvm-svn: 91084
2009-12-11 00:32:37 +00:00