llvm/mlir/lib/Dialect/LLVMIR/Transforms/InlinerInterfaceImpl.cpp

//===- InlinerInterfaceImpl.cpp - Inlining for LLVM the dialect -----------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// Logic for inlining LLVM functions and the definition of the
// LLVMInliningInterface.
//
//===----------------------------------------------------------------------===//

#include "mlir/Dialect/LLVMIR/Transforms/InlinerInterfaceImpl.h"
#include "mlir/Analysis/SliceWalk.h"
#include "mlir/Dialect/LLVMIR/LLVMDialect.h"
#include "mlir/IR/Matchers.h"
#include "mlir/Interfaces/DataLayoutInterfaces.h"
#include "mlir/Interfaces/ViewLikeInterface.h"
#include "mlir/Transforms/InliningUtils.h"
#include "llvm/ADT/ScopeExit.h"
#include "llvm/Support/Debug.h"

#define DEBUG_TYPE …

usingnamespacemlir;

/// Check whether the given alloca is an input to a lifetime intrinsic,
/// optionally passing through one or more casts on the way. This is not
/// transitive through block arguments.
static bool hasLifetimeMarkers(LLVM::AllocaOp allocaOp) { … }

/// Handles alloca operations in the inlined blocks:
/// - Moves all alloca operations with a constant size in the former entry block
///   of the callee into the entry block of the caller, so they become part of
///   the function prologue/epilogue during code generation.
/// - Inserts lifetime intrinsics that limit the scope of inlined static allocas
///   to the inlined blocks.
/// - Inserts StackSave and StackRestore operations if dynamic allocas were
///   inlined.
static void
handleInlinedAllocas(Operation *call,
                     iterator_range<Region::iterator> inlinedBlocks) { … }

/// Maps all alias scopes in the inlined operations to deep clones of the scopes
/// and domain. This is required for code such as `foo(a, b); foo(a2, b2);` to
/// not incorrectly return `noalias` for e.g. operations on `a` and `a2`.
static void
deepCloneAliasScopes(iterator_range<Region::iterator> inlinedBlocks) { … }

/// Creates a new ArrayAttr by concatenating `lhs` with `rhs`.
/// Returns null if both parameters are null. If only one attribute is null,
/// return the other.
static ArrayAttr concatArrayAttr(ArrayAttr lhs, ArrayAttr rhs) { … }

/// Attempts to return the set of all underlying pointer values that
/// `pointerValue` is based on. This function traverses through select
/// operations and block arguments.
static FailureOr<SmallVector<Value>>
getUnderlyingObjectSet(Value pointerValue) { … }

/// Creates a new AliasScopeAttr for every noalias parameter and attaches it to
/// the appropriate inlined memory operations in an attempt to preserve the
/// original semantics of the parameter attribute.
static void createNewAliasScopesFromNoAliasParameter(
    Operation *call, iterator_range<Region::iterator> inlinedBlocks) { … }

/// Appends any alias scopes of the call operation to any inlined memory
/// operation.
static void
appendCallOpAliasScopes(Operation *call,
                        iterator_range<Region::iterator> inlinedBlocks) { … }

/// Handles all interactions with alias scopes during inlining.
static void handleAliasScopes(Operation *call,
                              iterator_range<Region::iterator> inlinedBlocks) { … }

/// Appends any access groups of the call operation to any inlined memory
/// operation.
static void handleAccessGroups(Operation *call,
                               iterator_range<Region::iterator> inlinedBlocks) { … }

/// Updates locations inside loop annotations to reflect that they were inlined.
static void
handleLoopAnnotations(Operation *call,
                      iterator_range<Region::iterator> inlinedBlocks) { … }

/// If `requestedAlignment` is higher than the alignment specified on `alloca`,
/// realigns `alloca` if this does not exceed the natural stack alignment.
/// Returns the post-alignment of `alloca`, whether it was realigned or not.
static uint64_t tryToEnforceAllocaAlignment(LLVM::AllocaOp alloca,
                                            uint64_t requestedAlignment,
                                            DataLayout const &dataLayout) { … }

/// Tries to find and return the alignment of the pointer `value` by looking for
/// an alignment attribute on the defining allocation op or function argument.
/// If the found alignment is lower than `requestedAlignment`, tries to realign
/// the pointer, then returns the resulting post-alignment, regardless of
/// whether it was realigned or not. If no existing alignment attribute is
/// found, returns 1 (i.e., assume that no alignment is guaranteed).
static uint64_t tryToEnforceAlignment(Value value, uint64_t requestedAlignment,
                                      DataLayout const &dataLayout) { … }

/// Introduces a new alloca and copies the memory pointed to by `argument` to
/// the address of the new alloca, then returns the value of the new alloca.
static Value handleByValArgumentInit(OpBuilder &builder, Location loc,
                                     Value argument, Type elementType,
                                     uint64_t elementTypeSize,
                                     uint64_t targetAlignment) { … }

/// Handles a function argument marked with the byval attribute by introducing a
/// memcpy or realigning the defining operation, if required either due to the
/// pointee being writeable in the callee, and/or due to an alignment mismatch.
/// `requestedAlignment` specifies the alignment set in the "align" argument
/// attribute (or 1 if no align attribute was set).
static Value handleByValArgument(OpBuilder &builder, Operation *callable,
                                 Value argument, Type elementType,
                                 uint64_t requestedAlignment) { … }

namespace {
struct LLVMInlinerInterface : public DialectInlinerInterface { … };

} // end anonymous namespace

void mlir::LLVM::registerInlinerInterface(DialectRegistry &registry) { … }