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f3ff561c6f
This is phase-1 of switching from llvm::Optional to std::optional in the
next rebranch. llvm::Optional was removed from upstream LLVM, so we need
to migrate off rather soon. On Darwin, std::optional, and llvm::Optional
have the same layout, so we don't need to be as concerned about ABI
beyond the name mangling. `llvm::Optional` is only returned from one
function in
```
getStandardTypeSubst(StringRef TypeName,
bool allowConcurrencyManglings);
```
It's the return value, so it should not impact the mangling of the
function, and the layout is the same as `std::optional`, so it should be
mostly okay. This function doesn't appear to have users, and the ABI was
already broken 2 years ago for concurrency and no one seemed to notice
so this should be "okay".
I'm doing the migration incrementally so that folks working on main can
cherry-pick back to the release/5.9 branch. Once 5.9 is done and locked
away, then we can go through and finish the replacement. Since `None`
and `Optional` show up in contexts where they are not `llvm::None` and
`llvm::Optional`, I'm preparing the work now by going through and
removing the namespace unwrapping and making the `llvm` namespace
explicit. This should make it fairly mechanical to go through and
replace llvm::Optional with std::optional, and llvm::None with
std::nullopt. It's also a change that can be brought onto the
release/5.9 with minimal impact. This should be an NFC change.
102 lines
3.6 KiB
C++
102 lines
3.6 KiB
C++
//===--- ValueTracking.h - SIL Value Tracking Analysis ----------*- C++ -*-===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See https://swift.org/LICENSE.txt for license information
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// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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//
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// This file contains routines which analyze chains of computations.
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//
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//===----------------------------------------------------------------------===//
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#ifndef SWIFT_SILOPTIMIZER_ANALYSIS_VALUETRACKING_H
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#define SWIFT_SILOPTIMIZER_ANALYSIS_VALUETRACKING_H
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#include "swift/SIL/MemAccessUtils.h"
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#include "swift/SIL/SILArgument.h"
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#include "swift/SIL/SILInstruction.h"
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namespace swift {
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/// Returns true if \p V is a function argument which may not alias to
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/// any other pointer in the function.
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///
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/// This does not look through any projections. The caller must do that.
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bool isExclusiveArgument(SILValue V);
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/// Returns true if \p V is a locally allocated object.
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///
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/// Note: this may look through a single level of indirection (via
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/// ref_element_addr) when \p V is the address of a class property. However, it
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/// does not look through init/open_existential_addr.
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bool pointsToLocalObject(SILValue V);
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/// Returns true if \p V is a uniquely identified address or reference. Two
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/// uniquely identified pointers with distinct roots cannot alias. However, a
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/// uniquely identified pointer may alias with unidentified pointers. For
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/// example, the uniquely identified pointer may escape to a call that returns
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/// an alias of that pointer.
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///
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/// It may be any of:
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///
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/// - an address projection based on a locally allocated address with no
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/// indirection
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///
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/// - a locally allocated reference, or an address projection based on that
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/// reference with one level of indirection (an address into the locally
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/// allocated object).
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///
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/// - an address projection based on an exclusive argument with no levels of
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/// indirection (e.g. ref_element_addr, project_box, etc.).
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///
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/// TODO: Fold this into the AccessStorage API. pointsToLocalObject should be
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/// performed by AccessStorage::isUniquelyIdentified.
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inline bool isUniquelyIdentified(SILValue V) {
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SILValue objectRef = V;
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if (V->getType().isAddress()) {
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auto storage = AccessStorage::compute(V);
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if (!storage)
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return false;
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if (storage.isUniquelyIdentified())
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return true;
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if (!storage.isObjectAccess())
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return false;
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objectRef = storage.getObject();
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}
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return pointsToLocalObject(objectRef);
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}
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enum class IsZeroKind {
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Zero,
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NotZero,
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Unknown
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};
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/// Check if the value \p Value is known to be zero, non-zero or unknown.
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IsZeroKind isZeroValue(SILValue Value);
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/// Checks if a sign bit of a value is known to be set, not set or unknown.
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/// Essentially, it is a simple form of a range analysis.
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/// This approach is inspired by the corresponding implementation of
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/// ComputeSignBit in LLVM's value tracking implementation.
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/// It is planned to extend this approach to track all bits of a value.
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/// Therefore it can be considered to be the beginning of a range analysis
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/// infrastructure for the Swift compiler.
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llvm::Optional<bool> computeSignBit(SILValue Value);
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/// Check if execution of a given builtin instruction can result in overflows.
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/// Returns true of an overflow can happen. Otherwise returns false.
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bool canOverflow(BuiltinInst *BI);
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} // end namespace swift
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#endif // SWIFT_SILOPTIMIZER_ANALYSIS_VALUETRACKING_H
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