b2584e0b17
## Purpose This patch is one in a series of code-mods that annotate LLVM’s public interface for export. This patch annotates the `llvm/Transforms` library. These annotations currently have no meaningful impact on the LLVM build; however, they are a prerequisite to support an LLVM Windows DLL (shared library) build. ## Background This effort is tracked in #109483. Additional context is provided in [this discourse](https://discourse.llvm.org/t/psa-annotating-llvm-public-interface/85307), and documentation for `LLVM_ABI` and related annotations is found in the LLVM repo [here](https://github.com/llvm/llvm-project/blob/main/llvm/docs/InterfaceExportAnnotations.rst). The bulk of these changes were generated automatically using the [Interface Definition Scanner (IDS)](https://github.com/compnerd/ids) tool, followed formatting with `git clang-format`. The following manual adjustments were also applied after running IDS on Linux: - Removed a redundant `operator<<` from Attributor.h. IDS only auto-annotates the 1st declaration, and the 2nd declaration being un-annotated resulted in an "inconsistent linkage" error on Windows when building LLVM as a DLL. - `#include` the `VirtualFileSystem.h` in PGOInstrumentation.h and remove the local declaration of the `vfs::FileSystem` class. This is required because exporting the `PGOInstrumentationUse` constructor requires the class be fully defined because it is used by an argument. - Add #include "llvm/Support/Compiler.h" to files where it was not auto-added by IDS due to no pre-existing block of include statements. - Add `LLVM_TEMPLATE_ABI` and `LLVM_EXPORT_TEMPLATE` to exported instantiated templates. ## Validation Local builds and tests to validate cross-platform compatibility. This included llvm, clang, and lldb on the following configurations: - Windows with MSVC - Windows with Clang - Linux with GCC - Linux with Clang - Darwin with Clang
72 lines
2.9 KiB
C++
72 lines
2.9 KiB
C++
//===- LoopSimplify.h - Loop Canonicalization Pass --------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This pass performs several transformations to transform natural loops into a
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// simpler form, which makes subsequent analyses and transformations simpler and
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// more effective.
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//
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// Loop pre-header insertion guarantees that there is a single, non-critical
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// entry edge from outside of the loop to the loop header. This simplifies a
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// number of analyses and transformations, such as LICM.
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//
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// Loop exit-block insertion guarantees that all exit blocks from the loop
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// (blocks which are outside of the loop that have predecessors inside of the
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// loop) only have predecessors from inside of the loop (and are thus dominated
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// by the loop header). This simplifies transformations such as store-sinking
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// that are built into LICM.
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//
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// This pass also guarantees that loops will have exactly one backedge.
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//
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// Indirectbr instructions introduce several complications. If the loop
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// contains or is entered by an indirectbr instruction, it may not be possible
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// to transform the loop and make these guarantees. Client code should check
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// that these conditions are true before relying on them.
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//
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// Note that the simplifycfg pass will clean up blocks which are split out but
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// end up being unnecessary, so usage of this pass should not pessimize
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// generated code.
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//
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// This pass obviously modifies the CFG, but updates loop information and
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// dominator information.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_TRANSFORMS_UTILS_LOOPSIMPLIFY_H
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#define LLVM_TRANSFORMS_UTILS_LOOPSIMPLIFY_H
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#include "llvm/IR/PassManager.h"
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#include "llvm/Support/Compiler.h"
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namespace llvm {
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class AssumptionCache;
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class DominatorTree;
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class Loop;
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class LoopInfo;
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class MemorySSAUpdater;
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class ScalarEvolution;
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/// This pass is responsible for loop canonicalization.
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class LoopSimplifyPass : public PassInfoMixin<LoopSimplifyPass> {
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public:
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LLVM_ABI PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
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};
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/// Simplify each loop in a loop nest recursively.
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///
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/// This takes a potentially un-simplified loop L (and its children) and turns
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/// it into a simplified loop nest with preheaders and single backedges. It will
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/// update \c DominatorTree, \c LoopInfo, \c ScalarEvolution and \c MemorySSA
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/// analyses if they're non-null, and LCSSA if \c PreserveLCSSA is true.
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LLVM_ABI bool simplifyLoop(Loop *L, DominatorTree *DT, LoopInfo *LI,
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ScalarEvolution *SE, AssumptionCache *AC,
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MemorySSAUpdater *MSSAU, bool PreserveLCSSA);
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} // end namespace llvm
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#endif // LLVM_TRANSFORMS_UTILS_LOOPSIMPLIFY_H
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