Similar to memset, memset_pattern{4,8,16} all will return and do not
unwind. Use fallthrough to include all attributes also set for memset.
Reviewed By: nikic
Differential Revision: https://reviews.llvm.org/D114904
reallocf() is the same as realloc() but frees the input pointer
on failure as well. We can infer the same attributes.
Also combine some cases that infer the same attributes and are
logically related.
This reverts commit 29b6e967f3e99ac45340ea37a70262c70e4e7528. The bug it
found in PartiallyInlineLibCalls was fixed in
c8ffc73350dbb6044ca947bbead127b9b914cdf3.
This reverts commit ea75be3d9df448b6abafaf752a8141764d93ca33 and
1eb5b6e85045d22720f177a02aaf7097930e4b4f.
That commit caused crashes with compilation e.g. like this
(not fixed by the follow-up commit):
$ cat sqrt.c
float a;
b() { sqrt(a); }
$ clang -target x86_64-linux-gnu -c -O2 sqrt.c
Attributes 'readnone and writeonly' are incompatible!
%sqrtf = tail call float @sqrtf(float %0) #1
in function b
fatal error: error in backend: Broken function found, compilation aborted!
All of these functions would be `readnone`, but can't be on platforms
where they can set `errno`. A `writeonly` function with no pointer
arguments can only write (but never read) global state.
Writeonly theoretically allows these calls to be CSE'd (a writeonly call
with the same arguments will always result in the same global stores) or
hoisted out of loops, but that's not implemented currently.
There are a few functions in this list that could be `readnone` instead
of `writeonly`, if someone is interested.
Differential Revision: https://reviews.llvm.org/D116426
Add --match-full-lines or `{{$}}` to ensure that no unexpected
attributes appear at the ends of lines. Account for the cases
where attributes were in fact appearing.
Differential Revision: https://reviews.llvm.org/D110720
Add support for memset_pattern{4,8} similar to the existing
memset_pattern16 handling.
Reviewed By: ab
Differential Revision: https://reviews.llvm.org/D114883
`memcpy_chk` can be treated like `memcpy`, with the exception that it
may not return (if it aborts the program).
See D114793 for a similar patch for `memset_chk`.
Reviewed By: xbolva00
Differential Revision: https://reviews.llvm.org/D114863
The memset_chk library function should match memset's attributes with
respect of memory effects (argmemonly, writeonly). It also does not
raise exceptions. It may not return, in case it aborts the program.
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D114793
The intent of the negative #{{.*}} checks is to verify that the line
declaring/defining a function has no attribute, but they could restrict
later function declarations instead.
The 2008-09-02-FunctionNotes.ll check had allowed @fn3 to have an
attribute, because there is only a single "define void @fn3()" in the
output.
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D107614
Before D45736, getc_unlocked was available by default, but turned off
for non-Cygwin/non-MinGW Windows. D45736 then added 9 more unlocked
functions, which were unavailable by default, but it also:
* left getc_unlocked enabled by default,
* removed the disabling line for Windows, and
* added code to enable getc_unlocked for GNU, Android, and OSX.
For consistency, make getc_unlocked unavailable by default. Maybe this
was the intent of D45736 anyway.
Reviewed By: MaskRay, efriedma
Differential Revision: https://reviews.llvm.org/D107527
Reapply with fixes for clang tests.
-----
This is a simple enum attribute. Test changes are because enum
attributes are sorted before type attributes, so mustprogress is
now in a different position.
This reverts commit 84ed3a794b4ffe7bd673f1e5a17d507aa3113d12.
A number of clang tests are also affected by this change. Revert
until I can update them.
str(n)cat appends a copy of the second argument to the end of the first
argument. To find the end of the first argument, str(n)cat has to read
from it until it finds the terminating 0. So it should not be marked as
writeonly. I think this means the argument should not be marked as
writeonly.
(This is causing a mis-compile with legacy DSE, before it got removed)
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D100601
This reverts commit ab98f2c7129a52e216fd7e088b964cf4af27b0f2 and 98eea392cdbcdb7360e58b46e9329573f092cd96.
It includes a fix for the clang test which triggered the revert. I failed to notice this one because there was another AMDGPU llvm test with a similiar name and the exact same text in the error message. Odd. Since only one build bot reported the clang test, I didn't notice that one.
Breaks check-clang, see comments on D100400
Also revert follow-up "[NFC] Move a recently added utility into a location to enable reuse"
This reverts commit 3ce61fb6d697d49db471c7077b88b3b9ec9dec66.
This reverts commit 61a85da88235983da565bda0160367461fa0f382.
We have some cases today where attributes can be inferred from another on access, but the result is not explicitly materialized in IR. This change is a step towards changing that.
Why? Two main reasons:
* Human clarity. It's really confusing trying to figure out why a transform is triggering when the IR doesn't appear to have the required attributes.
* This avoids the need to special case declarations in e.g. functionattrs. Since we can assume the attribute is present, we can work directly from attributes (and only attributes) without also needing to query accessors on Function to avoid missing cases due to unannotated (but infered on use) declarations. (This piece will appear must easier to follow once D100226 also lands.)
Differential Revision: https://reviews.llvm.org/D100400
LLVM test Transforms/InferFunctionAttrs/annotate contains two RUN
invokation (UNKNOWN and NVPTX lines) which involve a CHECK-NOT directive
with a variable not defined by the enabled CHECK prefixes. This commit
fixes that by:
- enabling CHECK prefix for unknown target with specialisation when it
differs from other targets
- checking for absence of bcmp with any attribute for NVPTX
Reviewed By: tra
Differential Revision: https://reviews.llvm.org/D99589
This is a patch to explicitly mark the size parameter of allocator functions like malloc/realloc/... as noundef.
For C/C++: undef can be created from reading an uninitialized variable or padding.
Calling a function with uninitialized variable is already UB.
Calling malloc with padding value is.. something that's not expected. Padding bits may appear in a coerced aggregate, which doesn't apply to malloc's size.
Therefore, malloc's size can be marked as noundef.
For transformations that introduce malloc/realloc/..: I ran LLVM unit tests with an updated Alive2 semantics, and found no regression, so it seems okay.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D97045
These attributes were all incorrect or inappropriate for LLVM to infer:
- inaccessiblememonly is generally wrong; user replacement operator new
can access memory that's visible to the caller, as can a new_handler
function.
- willreturn is generally wrong; a custom new_handler is not guaranteed
to terminate.
- noalias is inappropriate: Clang has a flag to determine whether this
attribute should be present and adds it itself when appropriate.
- noundef and nonnull on the return value should be specified by the
frontend on all 'operator new' functions if we want them, not here.
In any case, inferring attributes on functions declared 'nobuiltin' (as
these are when Clang emits them) seems questionable.
Several of the new attributes here were incorrect, and even the ones
that are generally correct were being added even to nobuiltin calls.
This reverts commit bb3f169b59e1c8bd7fd70097532220bbd11e9967.
This patch marks some library functions as willreturn. On the first pass, I
excluded most functions that interact with streams/the filesystem.
Along with willreturn, it also adds nounwind to a set of math functions.
There probably are a few additional attributes we can add for those, but
that should be done separately.
Reviewed By: nikic
Differential Revision: https://reviews.llvm.org/D94684
This was missing as discovered by the SystemZ multistage bot:
http://lab.llvm.org:8011/#/builders/8, where wrong code resulted when this
extension was not performed.
Thanks for review by Ulrich Weigand and Roman Lebedev.
Differential Revision: https://reviews.llvm.org/D90760
This patch adds noundef to the returned pointers of allocators (malloc, calloc, ...)
and the pointer argument of free.
The returned pointer of allocators cannot be poison or (partially) undef.
Since the pointer that is given to free should precisely have zero offset,
it cannot be poison or (partially) undef too.
For the size arguments of allocators, noundef wasn't attached simply because
I wasn't sure whether attaching it is okay or not.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D87984
This patch follows D85345 and adds more noundef attributes to return values/arguments of library functions
that are mostly about accessing the file system or processes.
A few functions like `chmod` or `times` use typedef `mode_t` and `clock_t`.
They are neither struct nor union, so they cannot contain undef even if they're lowered to iN in IR. So, it is fine to add noundef to them.
- clock_t's actual type is size_t (C17, 7.27.1.3), so it isn't struct or union.
- For mode_t, either int or long is used in practice because programmers use bit manipulation. So, I think it is okay that it's never aggregate in practice.
After this patch, the remaining library functions are those that eagerly participate in optimizations: they can be removed, reordered, or
introduced by a transformation from primitive IR operations.
For them, a few testings is needed, since it may not be valid to add noundef anymore even if C standard says it's okay.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D85894
strspn, strncmp, strcspn, strcasecmp, strncasecmp, memcmp, memchr,
memrchr, memcpy, memmove, memcpy, mempcpy, strchr, strrchr, bcmp
should all only access memory through their arguments.
I broke out strcoll, strcasecmp, strncasecmp because the result
depends on the locale, which might get accessed through memory.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D86724
This patch adds noundef to return value and arguments of standard I/O functions.
With this patch, passing undef or poison to the functions becomes undefined
behavior in LLVM IR. Since undef/poison is lowered from operations having UB in C/C++,
passing undef to them was already UB in source.
With this patch, the functions cannot return undef or poison anymore as well.
According to C17 standard, ungetc/ungetwc/fgetpos/ftell can generate unspecified
value; 3.19.3 says unspecified value is a valid value of the relevant type,
and using unspecified value is unspecified behavior, which is not UB, so it
cannot be undef (using undef is UB when e.g. it is used at branch condition).
— The value of the file position indicator after a successful call to the ungetc function for a text stream, or the ungetwc function for any stream, until all pushed-back characters are read or discarded (7.21.7.10, 7.29.3.10).
— The details of the value stored by the fgetpos function (7.21.9.1).
— The details of the value returned by the ftell function for a text stream (7.21.9.4).
In the long run, most of the functions listed in BuildLibCalls should have noundefs; to remove redundant diffs which will anyway disappear in the future, I added noundef to a few more non-I/O functions as well.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D85345
This patch adds a function attribute, nofree, to indicate that a function does
not, directly or indirectly, call a memory-deallocation function (e.g., free,
C++'s operator delete).
Reviewers: jdoerfert
Differential Revision: https://reviews.llvm.org/D49165
llvm-svn: 365336
As it's causing some bot failures (and per request from kbarton).
This reverts commit r358543/ab70da07286e618016e78247e4a24fcb84077fda.
llvm-svn: 358546
