I checked that all of these out-of-line methods previously compiled to
simple loads and bittests, so they are pretty good candidates for
inlining. In particular, arg_size() and arg_empty() are popular and are
just two loads, so they seem worth inlining.
llvm-svn: 297963
Summary:
In rL291613, the section name was interned in LLVMContext. However,
this broke the ability to remove the section from a GlobalObject,
because it tried to intern empty strings, which is not allowed.
Fix that and add an appropriate regression test.
Reviewed By: rnk
Differential Revision: https://reviews.llvm.org/D29795
llvm-svn: 295238
Summary:
Convention wisdom says that bytes in Function are precious, and the
vast, vast majority of globals do not live in special sections. Even
when they do, they tend to live in the same section. Store the section
name on the LLVMContext in a StringSet, and maintain a map from
GlobalObject* to section name like we do for metadata, prefix data, etc.
The fact that we've survived this long wasting at least three pointers
of space in Function suggests that Function bytes are perhaps not as
precious as we once thought. Given that most functions have metadata
attachments when debug info is enabled, we might consider adding a
pointer here to make that access more efficient.
Reviewers: jlebar, dexonsmith, mehdi_amini
Subscribers: mehdi_amini, aprantl, llvm-commits
Differential Revision: https://reviews.llvm.org/D28150
llvm-svn: 291613
I added one for Value back in r262045, and I'm starting to think we
should have these for any class with bitfields whose memory efficiency
really matters.
llvm-svn: 290698
Summary:
Attaching !absolute_symbol to a global variable does two things:
1) Marks it as an absolute symbol reference.
2) Specifies the value range of that symbol's address.
Teach the X86 backend to allow absolute symbols to appear in place of
immediates by extending the relocImm and mov64imm32 matchers. Start using
relocImm in more places where it is legal.
As previously proposed on llvm-dev:
http://lists.llvm.org/pipermail/llvm-dev/2016-October/105800.html
Differential Revision: https://reviews.llvm.org/D25878
llvm-svn: 289087
These functions are about classifying a global which will actually be
emitted, so it does not make sense for them to take a GlobalValue which may
for example be an alias.
Change the Mach-O object writer and the Hexagon, Lanai and MIPS backends to
look through aliases before using TargetLoweringObjectFile interfaces. These
are functional changes but all appear to be bug fixes.
Differential Revision: https://reviews.llvm.org/D25917
llvm-svn: 285006
Summary: This reverts the changes to Globals.cpp and IRMover.cpp in
"[IR] Copy comdats in GlobalObject::copyAttributesFrom" (D20631,
rL270743).
The DeadArgElim test is left unchanged, and we change DAE to explicitly
copy comdats.
The reverted change breaks copyAttributesFrom when the destination lives
in a different module from the source. The decision in D21255 was to
revert this patch and handle comdat copying separately from
copyAttributesFrom.
Reviewers: majnemer, rnk
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D21403
llvm-svn: 272855
If a local_unnamed_addr attribute is attached to a global, the address
is known to be insignificant within the module. It is distinct from the
existing unnamed_addr attribute in that it only describes a local property
of the module rather than a global property of the symbol.
This attribute is intended to be used by the code generator and LTO to allow
the linker to decide whether the global needs to be in the symbol table. It is
possible to exclude a global from the symbol table if three things are true:
- This attribute is present on every instance of the global (which means that
the normal rule that the global must have a unique address can be broken without
being observable by the program by performing comparisons against the global's
address)
- The global has linkonce_odr linkage (which means that each linkage unit must have
its own copy of the global if it requires one, and the copy in each linkage unit
must be the same)
- It is a constant or a function (which means that the program cannot observe that
the unique-address rule has been broken by writing to the global)
Although this attribute could in principle be computed from the module
contents, LTO clients (i.e. linkers) will normally need to be able to compute
this property as part of symbol resolution, and it would be inefficient to
materialize every module just to compute it.
See:
http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20160509/356401.htmlhttp://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20160516/356738.html
for earlier discussion.
Part of the fix for PR27553.
Differential Revision: http://reviews.llvm.org/D20348
llvm-svn: 272709
This patch adds an IR, assembly and bitcode representation for metadata
attachments for globals. Future patches will port existing features to use
these new attachments.
Differential Revision: http://reviews.llvm.org/D20074
llvm-svn: 271348
This is probably correct for all uses except cross-module IR linking,
where we need to move the comdat from the source module to the
destination module.
Fixes PR27870.
Reviewers: majnemer
Differential Revision: http://reviews.llvm.org/D20631
llvm-svn: 270743
This patch add support for GCC attribute((ifunc("resolver"))) for
targets that use ELF as object file format. In general ifunc is a
special kind of function alias with type @gnu_indirect_function. Patch
for Clang http://reviews.llvm.org/D15524
Differential Revision: http://reviews.llvm.org/D15525
llvm-svn: 265667
This patch is a part of http://reviews.llvm.org/D15525
GlobalIndirectSymbol class contains common implementation for both
aliases and ifuncs. This patch should be NFC change that just prepare
common code for ifunc support.
Differential Revision: http://reviews.llvm.org/D18433
llvm-svn: 265016
Summary:
These are just helpers calling their static counter part to
simplify client code.
Reviewers: tejohnson
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D18339
From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 264382
Since the static getGlobalIdentifier and getGUID methods are now called
for global values other than functions, reflect that by moving these
methods to the GlobalValue class.
llvm-svn: 263524
The Use argument was used to compute the operand number for a fast
path when replacing only one operand. However we always have to go
through all the operands. So the argument number can be recomputed
locally anyway.
From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 260454
platforms.
With ELF, the alignment of a global variable in a shared library will
get copied into an executables linked against it, if the executable even
accesss the variable. So, it's not possible to implicitly increase
alignment based on access patterns, or you'll break existing binaries.
This happened to affect libc++'s std::cout symbol, for example. See
thread: http://thread.gmane.org/gmane.comp.compilers.clang.devel/45311
(This is a re-commit of r257719, without the bug reported in
PR26144. I've tweaked the code to not assert-fail in
enforceKnownAlignment when computeKnownBits doesn't recurse far enough
to find the underlying Alloca/GlobalObject value.)
Differential Revision: http://reviews.llvm.org/D16145
llvm-svn: 257902
platforms.
With ELF, the alignment of a global variable in a shared library will
get copied into an executables linked against it, if the executable even
accesss the variable. So, it's not possible to implicitly increase
alignment based on access patterns, or you'll break existing binaries.
This happened to affect libc++'s std::cout symbol, for example. See
thread: http://thread.gmane.org/gmane.comp.compilers.clang.devel/45311
llvm-svn: 257719
Stop converting implicitly between iterators and pointers/references in
lib/IR. For convenience, I've added a `getIterator()` accessor to
`ilist_node` so that callers don't need to know how to spell the
iterator class (i.e., they can use `X.getIterator()` instead of
`Function::iterator(X)`).
I'll eventually disallow these implicit conversions entirely, but
there's a lot of code, so it doesn't make sense to do it all in one
patch. One library or so at a time.
Why? To root out cases of `getNextNode()` and `getPrevNode()` being
used in iterator logic. The design of `ilist` makes that invalid when
the current node could be at the back of the list, but it happens to
"work" right now because of a bug where those functions never return
`nullptr` if you're using a half-node sentinel. Before I can fix the
function, I have to remove uses of it that rely on it misbehaving.
(Maybe the function should just be deleted anyway? But I don't want
deleting it -- potentially a huge project -- to block fixing
ilist/iplist.)
llvm-svn: 249782
This is needed by all GlobalObjects (GlobalAlias, Function,
GlobalVariable), see the GlobalObject::getValueType which is used in
many places. If at some point that can be removed, then we can remove
this member.
llvm-svn: 247621
This was a flawed change - it just caused the getElementType call to be
deferred until later, when we really need to remove it. Now that the IR
for GlobalAliases has been updated, the root cause is addressed that way
instead and this change is no longer needed (and in fact gets in the way
- because we want to pass the pointee type directly down further).
Follow up patches to push this through GlobalValue, bitcode format, etc,
will come along soon.
This reverts commit 236160.
llvm-svn: 247585
This is part of the work to devirtualize Value.
The old pattern was to call replaceUsesOfWithOnConstant which was overridden by
subclasses. Those could then call replaceUsesOfWithOnConstantImpl on Constant
to handle deleting the current value.
To be consistent with other parts of the code, this has been changed so that we
call the method on Constant, and that dispatches to an Impl on subclasses.
As part of this, it made sense to rename the methods to be more descriptive. The
new name is Constant::handleOperandChange, and it requires that all subclasses of
Constant implement handleOperandChangeImpl, even if they just throw an error if
they shouldn't be called.
Reviewed by Duncan Exon Smith.
llvm-svn: 240567
The only caller of this method is Value::replaceAllUsesWith which
explicitly checks that we are not a GlobalValue. So replace the
body with an unreachable to ensure that we never call it.
The unreachable itself is moved to GlobalValue not GlobalVariable
as that is the base class of all the globals we don't want to call
this method on.
Note, this patch is short lived as i'll soon refactor all callers
of this method.
llvm-svn: 240486
This reorganizes destroyConstant and destroyConstantImpl.
Now there is only destroyConstant in Constant itself, while
subclasses are required to implement destroyConstantImpl.
destroyConstantImpl no longer calls delete but is instead only
responsible for removing the constant from any maps in which it
is contained.
Reviewed by Duncan Exon Smith.
llvm-svn: 240471
This is to try make it very clear that subclasses shouldn't be changing
the value directly. Now that OperandList for normal instructions is computed
using the NumOperands, its critical that the NumOperands is accurate or we
could compute the wrong offset to the first operand.
I looked over all places which update NumOperands and they are all safe.
Hung off use User's don't use NumOperands to compute the OperandList so they
are safe to continue to manipulate it. The only other User which changed it
was GlobalVariable which has an optional init list but always allocated space
for a single Use. It was correctly setting NumOperands to 1 before setting an
initializer, and setting it to 0 after clearing the init list, so the order was safe.
Added some comments to that code to make sure that this isn't changed in future
without being aware of this constraint.
Reviewed by Duncan Exon Smith.
llvm-svn: 239621
Many of the callers already have the pointer type anyway, and for the
couple of callers that don't it's pretty easy to call PointerType::get
on the pointee type and address space.
This avoids LLParser from using PointerType::getElementType when parsing
GlobalAliases from IR.
llvm-svn: 236160
Summary:
This does not conceptually belongs here. Instead provide a shortcut
getModule() that provides access to the DataLayout.
Reviewers: chandlerc, echristo
Reviewed By: echristo
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D8027
From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 231147
To do this, change the representation of lazy loaded functions.
The previous representation cannot differentiate between a function whose body
has been removed and one whose body hasn't been read from the .bc file. That
means that in order to drop a function, the entire body had to be read.
llvm-svn: 220580
This new IR facility allows us to represent the object-file semantic of
a COMDAT group.
COMDATs allow us to tie together sections and make the inclusion of one
dependent on another. This is required to implement features like MS
ABI VFTables and optimizing away certain kinds of initialization in C++.
This functionality is only representable in COFF and ELF, Mach-O has no
similar mechanism.
Differential Revision: http://reviews.llvm.org/D4178
llvm-svn: 211920
This patch changes GlobalAlias to point to an arbitrary ConstantExpr and it is
up to MC (or the system assembler) to decide if that expression is valid or not.
This reduces our ability to diagnose invalid uses and how early we can spot
them, but it also lets us do things like
@test5 = alias inttoptr(i32 sub (i32 ptrtoint (i32* @test2 to i32),
i32 ptrtoint (i32* @bar to i32)) to i32*)
An important implication of this patch is that the notion of aliased global
doesn't exist any more. The alias has to encode the information needed to
access it in its metadata (linkage, visibility, type, etc).
Another consequence to notice is that getSection has to return a "const char *".
It could return a NullTerminatedStringRef if there was such a thing, but when
that was proposed the decision was to just uses "const char*" for that.
llvm-svn: 210062
This matches gcc's behavior. It also seems natural given that aliases
contain other properties that govern how it is accessed (linkage,
visibility, dll storage).
Clang still has to be updated to expose this feature to C.
llvm-svn: 209759
Craig Topper