1217 Commits

Author SHA1 Message Date
Vasileios Porpodas
cb5f239363 Revert "[NFC][IR] Make Module::getGlobalList() private"
This reverts commit ed3e3ee9e30dfbffd2170a770a49b36a7f444916.
2023-02-14 14:29:42 -08:00
Vasileios Porpodas
ed3e3ee9e3 [NFC][IR] Make Module::getGlobalList() private
This patch adds several missing GlobalList modifier functions, like
removeGlobalVariable(), eraseGlobalVariable() and insertGlobalVariable().
There is no longer need to access the list directly so it also makes
getGlobalList() private.

Differential Revision: https://reviews.llvm.org/D144027
2023-02-14 14:25:10 -08:00
Archibald Elliott
62c7f035b4 [NFC][TargetParser] Remove llvm/ADT/Triple.h
I also ran `git clang-format` to get the headers in the right order for
the new location, which has changed the order of other headers in two
files.
2023-02-07 12:39:46 +00:00
Guillaume Chatelet
9e845fe44f [NFC] Use GlobalObject::setAlignment that takes an Align in BitcodeReader 2023-02-01 09:35:11 +00:00
Matt Arsenault
778cf5431c IR: Add atomicrmw uinc_wrap and udec_wrap
These are essentially add/sub 1 with a clamping value.

AMDGPU has instructions for these. CUDA/HIP expose these as
atomicInc/atomicDec. Currently we use target intrinsics for these,
but those do no carry the ordering and syncscope. Add these to
atomicrmw so we can carry these and benefit from the regular
legalization processes.
2023-01-24 17:55:11 -04:00
Sebastian Neubauer
c33b9395b1 [BitcodeReader] Allow reading pointer types from old IR
When opaque pointers are enabled and old IR with typed pointers is read,
the BitcodeReader automatically upgrades all typed pointers to opaque
pointers. This is a lossy conversion, i.e. when a function argument is a
pointer and unused, it’s impossible to reconstruct the original type
behind the pointer.

There are cases where the type information of pointers is needed. One is
reading DXIL, which is bitcode of old LLVM IR and makes a lot of use of
pointers in function signatures.
We’d like to keep using up-to-date llvm to read in and process DXIL, so
in the face of opaque pointers, we need some way to access the type
information of pointers from the read bitcode.

This patch allows extracting type information by supplying functions to
parseBitcodeFile that get called for each function signature or metadata
value. The function can access the type information via the reader’s
type IDs and the getTypeByID and getContainedTypeID functions.
The tests exemplarily shows how type info from pointers can be stored in
metadata for use after the BitcodeReader finished.

Differential Revision: https://reviews.llvm.org/D127728
2023-01-18 13:20:15 +01:00
Nikita Popov
610abe8039 Revert "[BitcodeReader] Allow reading pointer types from old IR"
This reverts commit b56df190b01335506ce30a4559d880da76d1a181.

The unit tests are implemented in a way that requires support for
writing typed pointer bitcode, which is going away soon. Please
rewrite it in a way that not have requirement, e.g. by shipping
pre-compiled bitcode, as we do for integration tests.
2023-01-18 09:53:21 +01:00
Sebastian Neubauer
b56df190b0 [BitcodeReader] Allow reading pointer types from old IR
When opaque pointers are enabled and old IR with typed pointers is read,
the BitcodeReader automatically upgrades all typed pointers to opaque
pointers. This is a lossy conversion, i.e. when a function argument is a
pointer and unused, it’s impossible to reconstruct the original type
behind the pointer.

There are cases where the type information of pointers is needed. One is
reading DXIL, which is bitcode of old LLVM IR and makes a lot of use of
pointers in function signatures.
We’d like to keep using up-to-date llvm to read in and process DXIL, so
in the face of opaque pointers, we need some way to access the type
information of pointers from the read bitcode.

This patch allows extracting type information by supplying functions to
parseBitcodeFile that get called for each function signature or metadata
value. The function can access the type information via the reader’s
type IDs and the getTypeByID and getContainedTypeID functions.
The tests exemplarily shows how type info from pointers can be stored in
metadata for use after the BitcodeReader finished.

Differential Revision: https://reviews.llvm.org/D127728
2023-01-17 13:19:40 +01:00
Jannik Silvanus
df1a74ac3c [IR] Support importing modules with invalid data layouts.
Use the existing mechanism to change the data layout using callbacks.

Before this patch, we had a callback type DataLayoutCallbackTy that receives
a single StringRef specifying the target triple, and optionally returns
the data layout string to be used. Module loaders (both IR and BC) then
apply the callback to potentially override the module's data layout,
after first having imported and parsed the data layout from the file.

We can't do the same to fix invalid data layouts, because the import will already
fail, before the callback has a chance to fix it.
Instead, module loaders now tentatively parse the data layout into a string,
wait until the target triple has been parsed, apply the override callback
to the imported string and only then parse the tentative string as a data layout.

Moreover, add the old data layout string S as second argument to the callback,
in addition to the already existing target triple argument.
S is either the default data layout string in case none is specified, or the data
layout string specified in the module, possibly after auto-upgrades (for the BitcodeReader).
This allows callbacks to inspect the old data layout string,
and fix it instead of setting a fixed data layout.

Also allow to pass data layout override callbacks to lazy bitcode module
loader functions.

Differential Revision: https://reviews.llvm.org/D140985
2023-01-12 10:10:45 +01:00
Teresa Johnson
b1b9f1789e [MemProf] Fix combined index handling for locals
Since the linker does not resolve local symbols, we cannot look up
whether they are prevailing. The prior check was blocking all locals
from getting memprof summaries in the combined index.

Modified the existing test case to contain a local. This necessitated
some other fixes as the order of summary entries changed.

Differential Revision: https://reviews.llvm.org/D140786
2023-01-09 14:11:43 -08:00
serge-sans-paille
38818b60c5
Move from llvm::makeArrayRef to ArrayRef deduction guides - llvm/ part
Use deduction guides instead of helper functions.

The only non-automatic changes have been:

1. ArrayRef(some_uint8_pointer, 0) needs to be changed into ArrayRef(some_uint8_pointer, (size_t)0) to avoid an ambiguous call with ArrayRef((uint8_t*), (uint8_t*))
2. CVSymbol sym(makeArrayRef(symStorage)); needed to be rewritten as CVSymbol sym{ArrayRef(symStorage)}; otherwise the compiler is confused and thinks we have a (bad) function prototype. There was a few similar situation across the codebase.
3. ADL doesn't seem to work the same for deduction-guides and functions, so at some point the llvm namespace must be explicitly stated.
4. The "reference mode" of makeArrayRef(ArrayRef<T> &) that acts as no-op is not supported (a constructor cannot achieve that).

Per reviewers' comment, some useless makeArrayRef have been removed in the process.

This is a follow-up to https://reviews.llvm.org/D140896 that introduced
the deduction guides.

Differential Revision: https://reviews.llvm.org/D140955
2023-01-05 14:11:08 +01:00
Joshua Cranmer
e6b02214c6 [IR] Add a target extension type to LLVM.
Target-extension types represent types that need to be preserved through
optimization, but otherwise are not introspectable by target-independent
optimizations. This patch doesn't add any uses of these types by an existing
backend, it only provides basic infrastructure such that these types would work
correctly.

Reviewed By: nikic, barannikov88

Differential Revision: https://reviews.llvm.org/D135202
2022-12-20 11:02:11 -05:00
Vasileios Porpodas
32b38d248f [NFC] Rename Instruction::insertAt() to Instruction::insertInto(), to be consistent with BasicBlock::insertInto()
Differential Revision: https://reviews.llvm.org/D140085
2022-12-15 12:27:45 -08:00
Nikita Popov
e45cf47923 [Bitcode] Remove auto-detection for typed pointers
Always read bitcode according to the -opaque-pointers mode. Do not
perform auto-detection to implicitly switch to typed pointers.

This is a step towards removing typed pointer support, and also
eliminates the class of problems where linking may fail if a typed
pointer module is loaded before an opaque pointer module. (The
latest place where this was encountered is D139924, but this has
previously been fixed in other places doing bitcode linking as well.)

Differential Revision: https://reviews.llvm.org/D139940
2022-12-14 13:38:20 +01:00
Vasileios Porpodas
06911ba6ea [NFC] Cleanup: Replaces BB->getInstList().insert() with I->insertAt().
This is part of a series of cleanup patches towards making BasicBlock::getInstList() private.

Differential Revision: https://reviews.llvm.org/D138877
2022-12-12 13:33:05 -08:00
Krzysztof Parzyszek
49e75ebd85 [Bitcode(Reader|Writer)] Convert Optional to std::optional 2022-12-07 15:27:38 -08:00
Fangrui Song
89fae41ef1 [IR] llvm::Optional => std::optional
Many llvm/IR/* files have been migrated by other contributors.
This migrates most remaining files.
2022-12-05 04:13:11 +00:00
Kazu Hirata
e9e64f7c9e [Bitcode] Use std::nullopt instead of None (NFC)
This patch mechanically replaces None with std::nullopt where the
compiler would warn if None were deprecated.  The intent is to reduce
the amount of manual work required in migrating from Optional to
std::optional.

This is part of an effort to migrate from llvm::Optional to
std::optional:

https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716
2022-12-02 20:36:05 -08:00
Kazu Hirata
f960b935cc [Reader] Use std::optional in BitcodeReader.cpp (NFC)
This is part of an effort to migrate from llvm::Optional to
std::optional:

https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716
2022-11-25 11:33:20 -08:00
Matt Arsenault
0d527e56a5 GlobalIFunc: Make ifunc respect function address spaces 2022-11-22 21:42:44 -05:00
Teresa Johnson
9eacbba290 Restore "[MemProf] ThinLTO summary support" with more fixes
This restores commit 98ed423361de2f9dc0113a31be2aa04524489ca9 and
follow on fix 00c22351ba697dbddb4b5bf0ad94e4bcea4b316b, which were
reverted in 5d938eb6f79b16f55266dd23d5df831f552ea082 due to an
MSVC bot failure. I've included a fix for that failure.

Differential Revision: https://reviews.llvm.org/D135714
2022-11-16 09:42:41 -08:00
Jeremy Morse
5d938eb6f7 Revert "Restore "[MemProf] ThinLTO summary support" with fixes"
This reverts commit 00c22351ba697dbddb4b5bf0ad94e4bcea4b316b.
This reverts commit 98ed423361de2f9dc0113a31be2aa04524489ca9.

Seemingly MSVC has some kind of issue with this patch, in terms of linking:

  https://lab.llvm.org/buildbot/#/builders/123/builds/14137

I'll post more detail on D135714 momentarily.
2022-11-16 11:21:02 +00:00
Teresa Johnson
98ed423361 Restore "[MemProf] ThinLTO summary support" with fixes
This restores 47459455009db4790ffc3765a2ec0f8b4934c2a4, which was
reverted in commit 452a14efc84edf808d1e2953dad2c694972b312f, along with
fixes for a couple of bot failures.
2022-11-15 08:55:17 -08:00
Teresa Johnson
452a14efc8 Revert "[MemProf] ThinLTO summary support"
This reverts commit 47459455009db4790ffc3765a2ec0f8b4934c2a4.

Revert while I try to fix a couple of non-Linux build failures.
2022-11-15 07:39:40 -08:00
Teresa Johnson
4745945500 [MemProf] ThinLTO summary support
Implements the ThinLTO summary support for memprof related metadata.

This includes support for the assembly format, and for building the
summary from IR during ModuleSummaryAnalysis.

To reduce space in both the bitcode format and the in memory index,
we do 2 things:
1. We keep a single vector of all uniq stack id hashes, and record the
   index into this vector in the callsite and allocation memprof
   summaries.
2. When building the combined index during the LTO link, the callsite
   and allocation memprof summaries are only kept on the FunctionSummary
   of the prevailing copy.

Differential Revision: https://reviews.llvm.org/D135714
2022-11-15 06:45:12 -08:00
Nikita Popov
feda983ff8 [TableGen] Use MemoryEffects to represent intrinsic memory effects (NFCI)
The TableGen implementation was using a homegrown implementation of
FunctionModRefInfo. This switches it to use MemoryEffects instead.
This makes the code simpler, and will allow exposing the full
representational power of MemoryEffects in the future. Among other
things, this will allow us to map IntrHasSideEffects to an
inaccessiblemem readwrite, rather than just ignoring it entirely
in most cases.

To avoid layering issues, this moves the ModRef.h header from IR
to Support, so that it can be included in the TableGen layer.

Differential Revision: https://reviews.llvm.org/D137641
2022-11-14 10:52:04 +01:00
Nikita Popov
304f1d59ca [IR] Switch everything to use memory attribute
This switches everything to use the memory attribute proposed in
https://discourse.llvm.org/t/rfc-unify-memory-effect-attributes/65579.
The old argmemonly, inaccessiblememonly and inaccessiblemem_or_argmemonly
attributes are dropped. The readnone, readonly and writeonly attributes
are restricted to parameters only.

The old attributes are auto-upgraded both in bitcode and IR.
The bitcode upgrade is a policy requirement that has to be retained
indefinitely. The IR upgrade is mainly there so it's not necessary
to update all tests using memory attributes in this patch, which
is already large enough. We could drop that part after migrating
tests, or retain it longer term, to make it easier to import IR
from older LLVM versions.

High-level Function/CallBase APIs like doesNotAccessMemory() or
setDoesNotAccessMemory() are mapped transparently to the memory
attribute. Code that directly manipulates attributes (e.g. via
AttributeList) on the other hand needs to switch to working with
the memory attribute instead.

Differential Revision: https://reviews.llvm.org/D135780
2022-11-04 10:21:38 +01:00
Nikita Popov
e9754f0211 [IR] Add support for memory attribute
This implements IR and bitcode support for the memory attribute,
as specified in https://reviews.llvm.org/D135597.

The new attribute is not used for anything yet (and as such, the
old memory attributes are unaffected).

Differential Revision: https://reviews.llvm.org/D135592
2022-10-21 12:11:25 +02:00
Nikita Popov
c028329787 [Bitcode] Remove redundant intrinsic remangling (NFCI)
UpgradeIntrinsicFunction() is supposed to handle this already.
2022-10-21 11:50:09 +02:00
Teresa Johnson
646e25d051 [BitcodeReader] Convert pair to triple in preparation for MemProf (NFC)
Extracted from D135714 which adds summary support for MemProf. We will
need a 3rd tuple member in the ValueIdToValueInfoMap, this patch makes a
number of NFC changes to the existing clients of that map to reflect the
conversion of pair to tuple.
2022-10-19 13:34:30 -07:00
Ben Dunbobbin
7eee2a2d44 [IR] Don't allow DLL storage-class and local linkage
Disallow this meaningless combination. Doing so simplifies analysis
of LLVM code w.r.t t DLL storage-class, and prevents mistakes with
DLL storage class.

- Change the assembler to reject DLL storage class on symbols with
  local linkage.
- Change the bitcode reader to clear the DLL Storage class when the
  linkage is local for auto-upgrading
- Update LangRef.

There is an existing restriction on non-default visibility and local
linkage which this is modelled on.

Differential Review: https://reviews.llvm.org/D134784
2022-09-30 00:26:01 +01:00
Nikita Popov
96cb7c2273 [ConstantExpr] Remove fneg expression
As part of https://discourse.llvm.org/t/rfc-remove-most-constant-expressions/63179,
this removes the fneg constant expression (which is, incidentally,
the only unary operator expression).

Differential Revision: https://reviews.llvm.org/D133418
2022-09-08 10:24:55 +02:00
Nikita Popov
d452d5e2de [Bitcode] Fix constexpr autoupgrade for arrays and structs
While vectors use insertelement, structs and arrays should use
insertvalue.
2022-09-07 12:47:21 +02:00
Fangrui Song
de9d80c1c5 [llvm] LLVM_FALLTHROUGH => [[fallthrough]]. NFC
With C++17 there is no Clang pedantic warning or MSVC C5051.
2022-08-08 11:24:15 -07:00
Kazu Hirata
a2d4501718 [llvm] Fix comment typos (NFC) 2022-08-07 00:16:14 -07:00
Ellis Hoag
12e78ff881 [InstrProf] Add the skipprofile attribute
As discussed in [0], this diff adds the `skipprofile` attribute to
prevent the function from being profiled while allowing profiled
functions to be inlined into it. The `noprofile` attribute remains
unchanged.

The `noprofile` attribute is used for functions where it is
dangerous to add instrumentation to while the `skipprofile` attribute is
used to reduce code size or performance overhead.

[0] https://discourse.llvm.org/t/why-does-the-noprofile-attribute-restrict-inlining/64108

Reviewed By: phosek

Differential Revision: https://reviews.llvm.org/D130807
2022-08-04 08:45:27 -07:00
Nuno Lopes
fffabd5348 [NFC] Switch a few uses of undef to poison as placeholders for unreachable code 2022-07-30 13:55:56 +01:00
Arthur Eubanks
2eade1dba4 [WPD] Use new llvm.public.type.test intrinsic for potentially publicly visible classes
Turning on opaque pointers has uncovered an issue with WPD where we currently pattern match away `assume(type.test)` in WPD so that a later LTT doesn't resolve the type test to undef and introduce an `assume(false)`. The pattern matching can fail in cases where we transform two `assume(type.test)`s into `assume(phi(type.test.1, type.test.2))`.

Currently we create `assume(type.test)` for all virtual calls that might be devirtualized. This is to support `-Wl,--lto-whole-program-visibility`.

To prevent this, all virtual calls that may not be in the same LTO module instead use a new `llvm.public.type.test` intrinsic in place of the `llvm.type.test`. Then when we know if `-Wl,--lto-whole-program-visibility` is passed or not, we can either replace all `llvm.public.type.test` with `llvm.type.test`, or replace all `llvm.public.type.test` with `true`. This prevents WPD from trying to pattern match away `assume(type.test)` for public virtual calls when failing the pattern matching will result in miscompiles.

Reviewed By: tejohnson

Differential Revision: https://reviews.llvm.org/D128955
2022-07-26 08:01:08 -07:00
Nikita Popov
2a721374ae [IR] Don't use blockaddresses as callbr arguments
Following some recent discussions, this changes the representation
of callbrs in IR. The current blockaddress arguments are replaced
with `!` label constraints that refer directly to callbr indirect
destinations:

    ; Before:
    %res = callbr i8* asm "", "=r,r,i"(i8* %x, i8* blockaddress(@test8, %foo))
    to label %asm.fallthrough [label %foo]
    ; After:
    %res = callbr i8* asm "", "=r,r,!i"(i8* %x)
    to label %asm.fallthrough [label %foo]

The benefit of this is that we can easily update the successors of
a callbr, without having to worry about also updating blockaddress
references. This should allow us to remove some limitations:

* Allow unrolling/peeling/rotation of callbr, or any other
  clone-based optimizations
  (https://github.com/llvm/llvm-project/issues/41834)
* Allow duplicate successors
  (https://github.com/llvm/llvm-project/issues/45248)

This is just the IR representation change though, I will follow up
with patches to remove limtations in various transformation passes
that are no longer needed.

Differential Revision: https://reviews.llvm.org/D129288
2022-07-15 10:18:17 +02:00
Mitch Phillips
90e5a8ac47 Remove 'no_sanitize_memtag'. Add 'sanitize_memtag'.
For MTE globals, we should have clang emit the attribute for all GV's
that it creates, and then use that in the upcoming AArch64 global
tagging IR pass. We need a positive attribute for this sanitizer (rather
than implicit sanitization of all globals) because it needs to interact
with other parts of LLVM, including:

  1. Suppressing certain global optimisations (like merging),
  2. Emitting extra directives by the ASM writer, and
  3. Putting extra information in the symbol table entries.

While this does technically make the LLVM IR / bitcode format
non-backwards-compatible, nobody should have used this attribute yet,
because it's a no-op.

Reviewed By: eugenis

Differential Revision: https://reviews.llvm.org/D128950
2022-07-13 08:54:41 -07:00
Nick Desaulniers
2240d72f15 [X86] initial -mfunction-return=thunk-extern support
Adds support for:
* `-mfunction-return=<value>` command line flag, and
* `__attribute__((function_return("<value>")))` function attribute

Where the supported <value>s are:
* keep (disable)
* thunk-extern (enable)

thunk-extern enables clang to change ret instructions into jmps to an
external symbol named __x86_return_thunk, implemented as a new
MachineFunctionPass named "x86-return-thunks", keyed off the new IR
attribute fn_ret_thunk_extern.

The symbol __x86_return_thunk is expected to be provided by the runtime
the compiled code is linked against and is not defined by the compiler.
Enabling this option alone doesn't provide mitigations without
corresponding definitions of __x86_return_thunk!

This new MachineFunctionPass is very similar to "x86-lvi-ret".

The <value>s "thunk" and "thunk-inline" are currently unsupported. It's
not clear yet that they are necessary: whether the thunk pattern they
would emit is beneficial or used anywhere.

Should the <value>s "thunk" and "thunk-inline" become necessary,
x86-return-thunks could probably be merged into x86-retpoline-thunks
which has pre-existing machinery for emitting thunks (which could be
used to implement the <value> "thunk").

Has been found to build+boot with corresponding Linux
kernel patches. This helps the Linux kernel mitigate RETBLEED.
* CVE-2022-23816
* CVE-2022-28693
* CVE-2022-29901

See also:
* "RETBLEED: Arbitrary Speculative Code Execution with Return
Instructions."
* AMD SECURITY NOTICE AMD-SN-1037: AMD CPU Branch Type Confusion
* TECHNICAL GUIDANCE FOR MITIGATING BRANCH TYPE CONFUSION REVISION 1.0
  2022-07-12
* Return Stack Buffer Underflow / Return Stack Buffer Underflow /
  CVE-2022-29901, CVE-2022-28693 / INTEL-SA-00702

SystemZ may eventually want to support "thunk-extern" and "thunk"; both
options are used by the Linux kernel's CONFIG_EXPOLINE.

This functionality has been available in GCC since the 8.1 release, and
was backported to the 7.3 release.

Many thanks for folks that provided discrete review off list due to the
embargoed nature of this hardware vulnerability. Many Bothans died to
bring us this information.

Link: https://www.youtube.com/watch?v=IF6HbCKQHK8
Link: https://github.com/llvm/llvm-project/issues/54404
Link: https://gcc.gnu.org/legacy-ml/gcc-patches/2018-01/msg01197.html
Link: https://www.intel.com/content/www/us/en/developer/articles/technical/software-security-guidance/advisory-guidance/return-stack-buffer-underflow.html
Link: https://arstechnica.com/information-technology/2022/07/intel-and-amd-cpus-vulnerable-to-a-new-speculative-execution-attack/?comments=1
Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ce114c866860aa9eae3f50974efc68241186ba60
Link: https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00702.html
Link: https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00707.html

Reviewed By: aaron.ballman, craig.topper

Differential Revision: https://reviews.llvm.org/D129572
2022-07-12 09:17:54 -07:00
Nicolai Hähnle
ede600377c ManagedStatic: remove many straightforward uses in llvm
(Reapply after revert in e9ce1a588030d8d4004f5d7e443afe46245e9a92 due to
Fuchsia test failures. Removed changes in lib/ExecutionEngine/ other
than error categories, to be checked in more detail and reapplied
separately.)

Bulk remove many of the more trivial uses of ManagedStatic in the llvm
directory, either by defining a new getter function or, in many cases,
moving the static variable directly into the only function that uses it.

Differential Revision: https://reviews.llvm.org/D129120
2022-07-10 10:29:15 +02:00
Nicolai Hähnle
e9ce1a5880 Revert "ManagedStatic: remove many straightforward uses in llvm"
This reverts commit e6f1f062457c928c18a88c612f39d9e168f65a85.

Reverting due to a failure on the fuchsia-x86_64-linux buildbot.
2022-07-10 09:54:30 +02:00
Nicolai Hähnle
e6f1f06245 ManagedStatic: remove many straightforward uses in llvm
Bulk remove many of the more trivial uses of ManagedStatic in the llvm
directory, either by defining a new getter function or, in many cases,
moving the static variable directly into the only function that uses it.

Differential Revision: https://reviews.llvm.org/D129120
2022-07-10 09:15:08 +02:00
Shilei Tian
1023ddaf77 [LLVM] Add the support for fmax and fmin in atomicrmw instruction
This patch adds the support for `fmax` and `fmin` operations in `atomicrmw`
instruction. For now (at least in this patch), the instruction will be expanded
to CAS loop. There are already a couple of targets supporting the feature. I'll
create another patch(es) to enable them accordingly.

Reviewed By: arsenm

Differential Revision: https://reviews.llvm.org/D127041
2022-07-06 10:57:53 -04:00
Nikita Popov
11950efe06 [ConstExpr] Remove div/rem constant expressions
D128820 stopped creating div/rem constant expressions by default;
this patch removes support for them entirely.

The getUDiv(), getExactUDiv(), getSDiv(), getExactSDiv(), getURem()
and getSRem() on ConstantExpr are removed, and ConstantExpr::get()
now only accepts binary operators for which
ConstantExpr::isSupportedBinOp() returns true. Uses of these methods
may be replaced either by corresponding IRBuilder methods, or
ConstantFoldBinaryOpOperands (if a constant result is required).

On the C API side, LLVMConstUDiv, LLVMConstExactUDiv, LLVMConstSDiv,
LLVMConstExactSDiv, LLVMConstURem and LLVMConstSRem are removed and
corresponding LLVMBuild methods should be used.

Importantly, this also means that constant expressions can no longer
trap! This patch still keeps the canTrap() method to minimize diff --
I plan to drop it in a separate NFC patch.

Differential Revision: https://reviews.llvm.org/D129148
2022-07-06 10:11:34 +02:00
Fangrui Song
67854f9ed0 Use value_or instead of getValueOr. NFC 2022-06-29 21:55:02 -07:00
Nikita Popov
1271b8f57a [Bitcode] Restore bitcast expression auto-upgrade
Restore the autoupgrade from bitcast to ptrtoint+inttoptr, which
was lost as part of D127729.

This fixes the backwards compatibility issue noted in:
https://reviews.llvm.org/D127729#inline-1236519
2022-06-29 14:35:56 +02:00
Nikita Popov
941c8e0ea5 [Bitcode] Support expanding constant expressions into instructions
This implements an autoupgrade from constant expressions to
instructions, which is needed for
https://discourse.llvm.org/t/rfc-remove-most-constant-expressions/63179.

The basic approach is that constant expressions (CST_CODE_CE_*
records) now initially only create a BitcodeConstant value that
holds opcode, flags and operands IDs. Then, when the value actually
gets used, it can be converted either into a constant expression
(if that expression type is still supported) or into a sequence of
instructions. As currently all expressions are still supported,
-expand-constant-exprs is added for testing purposes, to force
expansion.

PHI nodes require special handling, because the constant expression
needs to be evaluated on the incoming edge. We do this by putting
it into a temporary block and then wiring it up appropriately
afterwards (for non-critical edges, we could also move the
instructions into the predecessor).

This also removes the need for the forward referenced constants
machinery, as the BitcodeConstants only hold value IDs. At the
point where the value is actually materialized, no forward
references are needed anymore.

Differential Revision: https://reviews.llvm.org/D127729
2022-06-28 11:09:46 +02:00
Kazu Hirata
7a47ee51a1 [llvm] Don't use Optional::getValue (NFC) 2022-06-20 22:45:45 -07:00