In addition to enabling ELFv2 homogeneous aggregate handling,
LLVM support to pass array types directly also enables a performance
enhancement. We can now pass (non-homogeneous) aggregates that fit
fully in registers as direct integer arrays, using an element type
to encode the alignment requirement (that would otherwise go to the
"byval align" field).
This is preferable since "byval" forces the back-end to write the
aggregate out to the stack, even if it could be passed fully in
registers. This is particularly annoying on ELFv2, if there is
no parameter save area available, since we then need to allocate
space on the callee's stack just to hold those aggregates.
Note that to implement this optimization, this patch does not attempt
to fully anticipate register allocation rules as (defined in the
ABI and) implemented in the back-end. Instead, the patch is simply
passing *any* aggregate passed by value using the array mechanism
if its size is up to 64 bytes. This means that some of those will
end up being passed in stack slots anyway, but the generated code
shouldn't be any worse either. (*Large* aggregates remain passed
using "byval" to enable optimized copying via memcpy etc.)
llvm-svn: 213495
This patch implements clang support for the PowerPC ELFv2 ABI.
Together with a series of companion patches in LLVM, this makes
clang/LLVM fully usable on powerpc64le-linux.
Most of the ELFv2 ABI changes are fully implemented on the LLVM side.
On the clang side, we only need to implement some changes in how
aggregate types are passed by value. Specifically, we need to:
- pass (and return) "homogeneous" floating-point or vector aggregates in
FPRs and VRs (this is similar to the ARM homogeneous aggregate ABI)
- return aggregates of up to 16 bytes in one or two GPRs
The second piece is trivial to implement in any case. To implement
the first piece, this patch makes use of infrastructure recently
enabled in the LLVM PowerPC back-end to support passing array types
directly, where the array element type encodes properties needed to
handle homogeneous aggregates correctly.
Specifically, the array element type encodes:
- whether the parameter should be passed in FPRs, VRs, or just
GPRs/stack slots (for float / vector / integer element types,
respectively)
- what the alignment requirements of the parameter are when passed in
GPRs/stack slots (8 for float / 16 for vector / the element type
size for integer element types) -- this corresponds to the
"byval align" field
With this support in place, the clang part simply needs to *detect*
whether an aggregate type implements a float / vector homogeneous
aggregate as defined by the ELFv2 ABI, and if so, pass/return it
as array type using the appropriate float / vector element type.
llvm-svn: 213494
In C99, an array parameter declarator might have the form:
direct-declarator '[' 'static' type-qual-list[opt] assign-expr ']'
where the static keyword indicates that the caller will always provide a
pointer to the beginning of an array with at least the number of elements
specified by the assignment expression. For constant sizes, we can use the
new dereferenceable attribute to pass this information to the optimizer. For
VLAs, we don't know the size, but (for addrspace(0)) do know that the pointer
must be nonnull (and so we can use the nonnull attribute).
llvm-svn: 213444
Thoroughly check for a pointer dereference which yields a glvalue. Look
through casts, comma operators, conditional operators, paren
expressions, etc.
This was originally D4416.
Differential Revision: http://reviews.llvm.org/D4592
llvm-svn: 213434
This reverts commit r213401, r213402, r213403, and r213404.
I accidently committed these changes instead of updating the
differential.
llvm-svn: 213405
Summary:
Thoroughly check for a pointer dereference which yields a glvalue. Look
through casts, comma operators, conditional operators, paren
expressions, etc.
Reviewers: rsmith
Subscribers: cfe-commits
Differential Revision: http://reviews.llvm.org/D4416
llvm-svn: 213401
Clang uses a diagnostic handler to grab diagnostic messages so it can print them
with the line of source code they refer to. This patch extends this to handle
optimization failures that were added to llvm to produce a warning when
loop vectorization is explicitly specified (using a pragma clang loop directive)
but fails.
Update renames warning flag name to avoid indicating the flag's severity and
adds a test.
Reviewed by Alp Toker
llvm-svn: 213400
Otherwise -fsanitize=vptr causes the program to crash when it downcasts
a null pointer.
Reviewed in http://reviews.llvm.org/D4412.
Patch by Byoungyoung Lee!
llvm-svn: 213393
Summary:
This change adds description of globals created by UBSan
instrumentation (UBSan handlers, type descriptors, filenames) to
llvm.asan.globals metadata, effectively "blacklisting" them. This can
dramatically decrease the data section in binaries built with UBSan+ASan,
as UBSan tends to create a lot of handlers, and ASan instrumentation
increases the global size to at least 64 bytes.
Test Plan: clang regression test suite
Reviewers: rsmith
Reviewed By: rsmith
Subscribers: cfe-commits, byoungyoung, kcc
Differential Revision: http://reviews.llvm.org/D4575
llvm-svn: 213392
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
r211898 introduced a regression where a large struct, which would
normally be passed ByVal, was causing padding to be inserted to
prevent the backend from using some GPRs, in order to follow the
AAPCS. However, the type of the argument was not being set correctly,
so the backend cannot align 8-byte aligned struct types on the stack.
The fix is to not insert the padding arguments when the argument is
being passed ByVal.
llvm-svn: 213359
This reverts commit r213307.
Reverting to have some on-list discussion/confirmation about the ongoing
direction of smart pointer usage in the LLVM project.
llvm-svn: 213325
(after fixing a bug in MultiplexConsumer I noticed the ownership of the
nested consumers was implemented with raw pointers - so this fixes
that... and follows the source back to its origin pushing unique_ptr
ownership up through there too)
llvm-svn: 213307
This makes us emit dllexported in-class initialized static data members (which
are treated as definitions in MSVC), even when they're not referenced.
It also makes their special linkage reflected in the GVA linkage instead of
getting massaged in CodeGen.
Differential Revision: http://reviews.llvm.org/D4563
llvm-svn: 213304
This is used to mark the instructions emitted by Clang to implement
variety of UBSan checks. Generally, we don't want to instrument these
instructions with another sanitizers (like ASan).
Reviewed in http://reviews.llvm.org/D4544
llvm-svn: 213291
-- a constructor list initialization that unpacked an initializer list into
constructor arguments and
-- a list initialization that created as std::initializer_list and passed it
as the first argument to a constructor
in the AST. Use this flag while instantiating templates to provide the right
semantics for the resulting initialization.
llvm-svn: 213224
Clang supports __assume, at least at the semantic level, when MS extensions are
enabled. Unfortunately, trying to actually compile code using __assume would
result in this error:
error: cannot compile this builtin function yet
__assume is an optimizer hint, and can be ignored at the IR level. Until LLVM
supports assumptions at the IR level, a noop lowering is valid, and that is
what is done here.
llvm-svn: 213206
to be applied to class or protocols. This will direct IRGen
for Objective-C metadata to use the new name in various places
where class and protocol names are needed.
rdar:// 17631257
llvm-svn: 213167
Clang uses a diagnostic handler to grab diagnostic messages so it can print them
with the line of source code they refer to. This patch extends this to handle
diagnostic warnings that were added to llvm to produce a warning when
loop vectorization is explicitly specified (using a pragma clang loop directive)
but fails.
Reviewed by: Aaron Ballman
llvm-svn: 213112
This patch implements __builtin_arm_nop intrinsic for AArch32 and AArch64,
which generates hint 0x0, the alias of NOP instruction.
This intrinsic is necessary to implement ACLE __nop intrinsic.
Differential Revision: http://reviews.llvm.org/D4495
llvm-svn: 212947
Previously, we would have a private backing variable and an internal
alias pointing at it.
However, -fdata-sections only fires if a global variable has non-private
linkage. This means that an unreferenced vftable wouldn't get
discarded, bloating the object file.
Instead, stick the backing variable in a comdat even if the alias has
internal linkage. This will allow the linker to drop the vftable if it
is unused.
llvm-svn: 212901
Currently ASan instrumentation pass creates a string with global name
for each instrumented global (to include global names in the error report). Global
name is already mangled at this point, and we may not be able to demangle it
at runtime (e.g. there is no __cxa_demangle on Android).
Instead, create a string with fully qualified global name in Clang, and pass it
to ASan instrumentation pass in llvm.asan.globals metadata. If there is no metadata
for some global, ASan will use the original algorithm.
This fixes https://code.google.com/p/address-sanitizer/issues/detail?id=264.
llvm-svn: 212872
OS X TLS has all accesses going through the thread-wrapper function and
gives the backing thread-local variable internal linkage. This means
that thread-wrappers must have WeakAnyLinkage so that references to the
internal thread-local variables do not get propagated to other code.
It also means that translation units which do not provide a definition
for the thread-local variable cannot attempt to emit a thread-wrapper
because the thread wrapper will attempt to reference the backing
variable.
Differential Revision: http://reviews.llvm.org/D4109
llvm-svn: 212841
We now have an LLVM-level nonnull attribute that can be applied to function
parameters, and we emit it for reference types (as of r209723), but did not
emit it when an __attribute__((nonnull)) was provided. Now we will.
llvm-svn: 212835
Teach UBSan vptr checker to ignore technically invalud down-casts on
blacklisted types.
Based on http://reviews.llvm.org/D4407 by Byoungyoung Lee!
llvm-svn: 212770
Alexander Musman