Merge "Update prebuilt Clang to r353983." into p9.0HEADp9.0-backupp9.0

1 files changed, 513 insertions, 0 deletions

diff --git a/clang-r353983/include/llvm/Transforms/Utils/Local.h b/clang-r353983/include/llvm/Transforms/Utils/Local.h
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+//===- Local.h - Functions to perform local transformations -----*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// This family of functions perform various local transformations to the
+// program.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_TRANSFORMS_UTILS_LOCAL_H
+#define LLVM_TRANSFORMS_UTILS_LOCAL_H
+
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/TinyPtrVector.h"
+#include "llvm/Analysis/AliasAnalysis.h"
+#include "llvm/Analysis/DomTreeUpdater.h"
+#include "llvm/Analysis/Utils/Local.h"
+#include "llvm/IR/Constant.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/Dominators.h"
+#include "llvm/IR/GetElementPtrTypeIterator.h"
+#include "llvm/IR/Operator.h"
+#include "llvm/IR/Type.h"
+#include "llvm/IR/User.h"
+#include "llvm/IR/Value.h"
+#include "llvm/Support/Casting.h"
+#include <cstdint>
+#include <limits>
+
+namespace llvm {
+
+class AllocaInst;
+class AssumptionCache;
+class BasicBlock;
+class BranchInst;
+class CallInst;
+class DbgVariableIntrinsic;
+class DbgValueInst;
+class DIBuilder;
+class Function;
+class Instruction;
+class LazyValueInfo;
+class LoadInst;
+class MDNode;
+class MemorySSAUpdater;
+class PHINode;
+class StoreInst;
+class TargetLibraryInfo;
+class TargetTransformInfo;
+
+/// A set of parameters used to control the transforms in the SimplifyCFG pass.
+/// Options may change depending on the position in the optimization pipeline.
+/// For example, canonical form that includes switches and branches may later be
+/// replaced by lookup tables and selects.
+struct SimplifyCFGOptions {
+  int BonusInstThreshold;
+  bool ForwardSwitchCondToPhi;
+  bool ConvertSwitchToLookupTable;
+  bool NeedCanonicalLoop;
+  bool SinkCommonInsts;
+  AssumptionCache *AC;
+
+  SimplifyCFGOptions(unsigned BonusThreshold = 1,
+                     bool ForwardSwitchCond = false,
+                     bool SwitchToLookup = false, bool CanonicalLoops = true,
+                     bool SinkCommon = false,
+                     AssumptionCache *AssumpCache = nullptr)
+      : BonusInstThreshold(BonusThreshold),
+        ForwardSwitchCondToPhi(ForwardSwitchCond),
+        ConvertSwitchToLookupTable(SwitchToLookup),
+        NeedCanonicalLoop(CanonicalLoops),
+        SinkCommonInsts(SinkCommon),
+        AC(AssumpCache) {}
+
+  // Support 'builder' pattern to set members by name at construction time.
+  SimplifyCFGOptions &bonusInstThreshold(int I) {
+    BonusInstThreshold = I;
+    return *this;
+  }
+  SimplifyCFGOptions &forwardSwitchCondToPhi(bool B) {
+    ForwardSwitchCondToPhi = B;
+    return *this;
+  }
+  SimplifyCFGOptions &convertSwitchToLookupTable(bool B) {
+    ConvertSwitchToLookupTable = B;
+    return *this;
+  }
+  SimplifyCFGOptions &needCanonicalLoops(bool B) {
+    NeedCanonicalLoop = B;
+    return *this;
+  }
+  SimplifyCFGOptions &sinkCommonInsts(bool B) {
+    SinkCommonInsts = B;
+    return *this;
+  }
+  SimplifyCFGOptions &setAssumptionCache(AssumptionCache *Cache) {
+    AC = Cache;
+    return *this;
+  }
+};
+
+//===----------------------------------------------------------------------===//
+//  Local constant propagation.
+//
+
+/// If a terminator instruction is predicated on a constant value, convert it
+/// into an unconditional branch to the constant destination.
+/// This is a nontrivial operation because the successors of this basic block
+/// must have their PHI nodes updated.
+/// Also calls RecursivelyDeleteTriviallyDeadInstructions() on any branch/switch
+/// conditions and indirectbr addresses this might make dead if
+/// DeleteDeadConditions is true.
+bool ConstantFoldTerminator(BasicBlock *BB, bool DeleteDeadConditions = false,
+                            const TargetLibraryInfo *TLI = nullptr,
+                            DomTreeUpdater *DTU = nullptr);
+
+//===----------------------------------------------------------------------===//
+//  Local dead code elimination.
+//
+
+/// Return true if the result produced by the instruction is not used, and the
+/// instruction has no side effects.
+bool isInstructionTriviallyDead(Instruction *I,
+                                const TargetLibraryInfo *TLI = nullptr);
+
+/// Return true if the result produced by the instruction would have no side
+/// effects if it was not used. This is equivalent to checking whether
+/// isInstructionTriviallyDead would be true if the use count was 0.
+bool wouldInstructionBeTriviallyDead(Instruction *I,
+                                     const TargetLibraryInfo *TLI = nullptr);
+
+/// If the specified value is a trivially dead instruction, delete it.
+/// If that makes any of its operands trivially dead, delete them too,
+/// recursively. Return true if any instructions were deleted.
+bool RecursivelyDeleteTriviallyDeadInstructions(
+    Value *V, const TargetLibraryInfo *TLI = nullptr,
+    MemorySSAUpdater *MSSAU = nullptr);
+
+/// Delete all of the instructions in `DeadInsts`, and all other instructions
+/// that deleting these in turn causes to be trivially dead.
+///
+/// The initial instructions in the provided vector must all have empty use
+/// lists and satisfy `isInstructionTriviallyDead`.
+///
+/// `DeadInsts` will be used as scratch storage for this routine and will be
+/// empty afterward.
+void RecursivelyDeleteTriviallyDeadInstructions(
+    SmallVectorImpl<Instruction *> &DeadInsts,
+    const TargetLibraryInfo *TLI = nullptr, MemorySSAUpdater *MSSAU = nullptr);
+
+/// If the specified value is an effectively dead PHI node, due to being a
+/// def-use chain of single-use nodes that either forms a cycle or is terminated
+/// by a trivially dead instruction, delete it. If that makes any of its
+/// operands trivially dead, delete them too, recursively. Return true if a
+/// change was made.
+bool RecursivelyDeleteDeadPHINode(PHINode *PN,
+                                  const TargetLibraryInfo *TLI = nullptr);
+
+/// Scan the specified basic block and try to simplify any instructions in it
+/// and recursively delete dead instructions.
+///
+/// This returns true if it changed the code, note that it can delete
+/// instructions in other blocks as well in this block.
+bool SimplifyInstructionsInBlock(BasicBlock *BB,
+                                 const TargetLibraryInfo *TLI = nullptr);
+
+/// Replace all the uses of an SSA value in @llvm.dbg intrinsics with
+/// undef. This is useful for signaling that a variable, e.g. has been
+/// found dead and hence it's unavailable at a given program point.
+/// Returns true if the dbg values have been changed.
+bool replaceDbgUsesWithUndef(Instruction *I);
+
+//===----------------------------------------------------------------------===//
+//  Control Flow Graph Restructuring.
+//
+
+/// Like BasicBlock::removePredecessor, this method is called when we're about
+/// to delete Pred as a predecessor of BB. If BB contains any PHI nodes, this
+/// drops the entries in the PHI nodes for Pred.
+///
+/// Unlike the removePredecessor method, this attempts to simplify uses of PHI
+/// nodes that collapse into identity values.  For example, if we have:
+///   x = phi(1, 0, 0, 0)
+///   y = and x, z
+///
+/// .. and delete the predecessor corresponding to the '1', this will attempt to
+/// recursively fold the 'and' to 0.
+void RemovePredecessorAndSimplify(BasicBlock *BB, BasicBlock *Pred,
+                                  DomTreeUpdater *DTU = nullptr);
+
+/// BB is a block with one predecessor and its predecessor is known to have one
+/// successor (BB!). Eliminate the edge between them, moving the instructions in
+/// the predecessor into BB. This deletes the predecessor block.
+void MergeBasicBlockIntoOnlyPred(BasicBlock *BB, DomTreeUpdater *DTU = nullptr);
+
+/// BB is known to contain an unconditional branch, and contains no instructions
+/// other than PHI nodes, potential debug intrinsics and the branch. If
+/// possible, eliminate BB by rewriting all the predecessors to branch to the
+/// successor block and return true. If we can't transform, return false.
+bool TryToSimplifyUncondBranchFromEmptyBlock(BasicBlock *BB,
+                                             DomTreeUpdater *DTU = nullptr);
+
+/// Check for and eliminate duplicate PHI nodes in this block. This doesn't try
+/// to be clever about PHI nodes which differ only in the order of the incoming
+/// values, but instcombine orders them so it usually won't matter.
+bool EliminateDuplicatePHINodes(BasicBlock *BB);
+
+/// This function is used to do simplification of a CFG.  For example, it
+/// adjusts branches to branches to eliminate the extra hop, it eliminates
+/// unreachable basic blocks, and does other peephole optimization of the CFG.
+/// It returns true if a modification was made, possibly deleting the basic
+/// block that was pointed to. LoopHeaders is an optional input parameter
+/// providing the set of loop headers that SimplifyCFG should not eliminate.
+bool simplifyCFG(BasicBlock *BB, const TargetTransformInfo &TTI,
+                 const SimplifyCFGOptions &Options = {},
+                 SmallPtrSetImpl<BasicBlock *> *LoopHeaders = nullptr);
+
+/// This function is used to flatten a CFG. For example, it uses parallel-and
+/// and parallel-or mode to collapse if-conditions and merge if-regions with
+/// identical statements.
+bool FlattenCFG(BasicBlock *BB, AliasAnalysis *AA = nullptr);
+
+/// If this basic block is ONLY a setcc and a branch, and if a predecessor
+/// branches to us and one of our successors, fold the setcc into the
+/// predecessor and use logical operations to pick the right destination.
+bool FoldBranchToCommonDest(BranchInst *BI, unsigned BonusInstThreshold = 1);
+
+/// This function takes a virtual register computed by an Instruction and
+/// replaces it with a slot in the stack frame, allocated via alloca.
+/// This allows the CFG to be changed around without fear of invalidating the
+/// SSA information for the value. It returns the pointer to the alloca inserted
+/// to create a stack slot for X.
+AllocaInst *DemoteRegToStack(Instruction &X,
+                             bool VolatileLoads = false,
+                             Instruction *AllocaPoint = nullptr);
+
+/// This function takes a virtual register computed by a phi node and replaces
+/// it with a slot in the stack frame, allocated via alloca. The phi node is
+/// deleted and it returns the pointer to the alloca inserted.
+AllocaInst *DemotePHIToStack(PHINode *P, Instruction *AllocaPoint = nullptr);
+
+/// Try to ensure that the alignment of \p V is at least \p PrefAlign bytes. If
+/// the owning object can be modified and has an alignment less than \p
+/// PrefAlign, it will be increased and \p PrefAlign returned. If the alignment
+/// cannot be increased, the known alignment of the value is returned.
+///
+/// It is not always possible to modify the alignment of the underlying object,
+/// so if alignment is important, a more reliable approach is to simply align
+/// all global variables and allocation instructions to their preferred
+/// alignment from the beginning.
+unsigned getOrEnforceKnownAlignment(Value *V, unsigned PrefAlign,
+                                    const DataLayout &DL,
+                                    const Instruction *CxtI = nullptr,
+                                    AssumptionCache *AC = nullptr,
+                                    const DominatorTree *DT = nullptr);
+
+/// Try to infer an alignment for the specified pointer.
+inline unsigned getKnownAlignment(Value *V, const DataLayout &DL,
+                                  const Instruction *CxtI = nullptr,
+                                  AssumptionCache *AC = nullptr,
+                                  const DominatorTree *DT = nullptr) {
+  return getOrEnforceKnownAlignment(V, 0, DL, CxtI, AC, DT);
+}
+
+///===---------------------------------------------------------------------===//
+///  Dbg Intrinsic utilities
+///
+
+/// Inserts a llvm.dbg.value intrinsic before a store to an alloca'd value
+/// that has an associated llvm.dbg.declare or llvm.dbg.addr intrinsic.
+void ConvertDebugDeclareToDebugValue(DbgVariableIntrinsic *DII,
+                                     StoreInst *SI, DIBuilder &Builder);
+
+/// Inserts a llvm.dbg.value intrinsic before a load of an alloca'd value
+/// that has an associated llvm.dbg.declare or llvm.dbg.addr intrinsic.
+void ConvertDebugDeclareToDebugValue(DbgVariableIntrinsic *DII,
+                                     LoadInst *LI, DIBuilder &Builder);
+
+/// Inserts a llvm.dbg.value intrinsic after a phi that has an associated
+/// llvm.dbg.declare or llvm.dbg.addr intrinsic.
+void ConvertDebugDeclareToDebugValue(DbgVariableIntrinsic *DII,
+                                     PHINode *LI, DIBuilder &Builder);
+
+/// Lowers llvm.dbg.declare intrinsics into appropriate set of
+/// llvm.dbg.value intrinsics.
+bool LowerDbgDeclare(Function &F);
+
+/// Propagate dbg.value intrinsics through the newly inserted PHIs.
+void insertDebugValuesForPHIs(BasicBlock *BB,
+                              SmallVectorImpl<PHINode *> &InsertedPHIs);
+
+/// Finds all intrinsics declaring local variables as living in the memory that
+/// 'V' points to. This may include a mix of dbg.declare and
+/// dbg.addr intrinsics.
+TinyPtrVector<DbgVariableIntrinsic *> FindDbgAddrUses(Value *V);
+
+/// Finds the llvm.dbg.value intrinsics describing a value.
+void findDbgValues(SmallVectorImpl<DbgValueInst *> &DbgValues, Value *V);
+
+/// Finds the debug info intrinsics describing a value.
+void findDbgUsers(SmallVectorImpl<DbgVariableIntrinsic *> &DbgInsts, Value *V);
+
+/// Replaces llvm.dbg.declare instruction when the address it
+/// describes is replaced with a new value. If Deref is true, an
+/// additional DW_OP_deref is prepended to the expression. If Offset
+/// is non-zero, a constant displacement is added to the expression
+/// (between the optional Deref operations). Offset can be negative.
+bool replaceDbgDeclare(Value *Address, Value *NewAddress,
+                       Instruction *InsertBefore, DIBuilder &Builder,
+                       bool DerefBefore, int Offset, bool DerefAfter);
+
+/// Replaces llvm.dbg.declare instruction when the alloca it describes
+/// is replaced with a new value. If Deref is true, an additional
+/// DW_OP_deref is prepended to the expression. If Offset is non-zero,
+/// a constant displacement is added to the expression (between the
+/// optional Deref operations). Offset can be negative. The new
+/// llvm.dbg.declare is inserted immediately after AI.
+bool replaceDbgDeclareForAlloca(AllocaInst *AI, Value *NewAllocaAddress,
+                                DIBuilder &Builder, bool DerefBefore,
+                                int Offset, bool DerefAfter);
+
+/// Replaces multiple llvm.dbg.value instructions when the alloca it describes
+/// is replaced with a new value. If Offset is non-zero, a constant displacement
+/// is added to the expression (after the mandatory Deref). Offset can be
+/// negative. New llvm.dbg.value instructions are inserted at the locations of
+/// the instructions they replace.
+void replaceDbgValueForAlloca(AllocaInst *AI, Value *NewAllocaAddress,
+                              DIBuilder &Builder, int Offset = 0);
+
+/// Assuming the instruction \p I is going to be deleted, attempt to salvage
+/// debug users of \p I by writing the effect of \p I in a DIExpression.
+/// Returns true if any debug users were updated.
+bool salvageDebugInfo(Instruction &I);
+
+/// Implementation of salvageDebugInfo, applying only to instructions in
+/// \p Insns, rather than all debug users of \p I.
+bool salvageDebugInfoForDbgValues(Instruction &I,
+                                  ArrayRef<DbgVariableIntrinsic *> Insns);
+
+/// Given an instruction \p I and DIExpression \p DIExpr operating on it, write
+/// the effects of \p I into the returned DIExpression, or return nullptr if
+/// it cannot be salvaged. \p StackVal: whether DW_OP_stack_value should be
+/// appended to the expression.
+DIExpression *salvageDebugInfoImpl(Instruction &I, DIExpression *DIExpr,
+                                   bool StackVal);
+
+/// Point debug users of \p From to \p To or salvage them. Use this function
+/// only when replacing all uses of \p From with \p To, with a guarantee that
+/// \p From is going to be deleted.
+///
+/// Follow these rules to prevent use-before-def of \p To:
+///   . If \p To is a linked Instruction, set \p DomPoint to \p To.
+///   . If \p To is an unlinked Instruction, set \p DomPoint to the Instruction
+///     \p To will be inserted after.
+///   . If \p To is not an Instruction (e.g a Constant), the choice of
+///     \p DomPoint is arbitrary. Pick \p From for simplicity.
+///
+/// If a debug user cannot be preserved without reordering variable updates or
+/// introducing a use-before-def, it is either salvaged (\ref salvageDebugInfo)
+/// or deleted. Returns true if any debug users were updated.
+bool replaceAllDbgUsesWith(Instruction &From, Value &To, Instruction &DomPoint,
+                           DominatorTree &DT);
+
+/// Remove all instructions from a basic block other than it's terminator
+/// and any present EH pad instructions.
+unsigned removeAllNonTerminatorAndEHPadInstructions(BasicBlock *BB);
+
+/// Insert an unreachable instruction before the specified
+/// instruction, making it and the rest of the code in the block dead.
+unsigned changeToUnreachable(Instruction *I, bool UseLLVMTrap,
+                             bool PreserveLCSSA = false,
+                             DomTreeUpdater *DTU = nullptr);
+
+/// Convert the CallInst to InvokeInst with the specified unwind edge basic
+/// block.  This also splits the basic block where CI is located, because
+/// InvokeInst is a terminator instruction.  Returns the newly split basic
+/// block.
+BasicBlock *changeToInvokeAndSplitBasicBlock(CallInst *CI,
+                                             BasicBlock *UnwindEdge);
+
+/// Replace 'BB's terminator with one that does not have an unwind successor
+/// block. Rewrites `invoke` to `call`, etc. Updates any PHIs in unwind
+/// successor.
+///
+/// \param BB  Block whose terminator will be replaced.  Its terminator must
+///            have an unwind successor.
+void removeUnwindEdge(BasicBlock *BB, DomTreeUpdater *DTU = nullptr);
+
+/// Remove all blocks that can not be reached from the function's entry.
+///
+/// Returns true if any basic block was removed.
+bool removeUnreachableBlocks(Function &F, LazyValueInfo *LVI = nullptr,
+                             DomTreeUpdater *DTU = nullptr,
+                             MemorySSAUpdater *MSSAU = nullptr);
+
+/// Combine the metadata of two instructions so that K can replace J. Some
+/// metadata kinds can only be kept if K does not move, meaning it dominated
+/// J in the original IR.
+///
+/// Metadata not listed as known via KnownIDs is removed
+void combineMetadata(Instruction *K, const Instruction *J,
+                     ArrayRef<unsigned> KnownIDs, bool DoesKMove);
+
+/// Combine the metadata of two instructions so that K can replace J. This
+/// specifically handles the case of CSE-like transformations. Some
+/// metadata can only be kept if K dominates J. For this to be correct,
+/// K cannot be hoisted.
+///
+/// Unknown metadata is removed.
+void combineMetadataForCSE(Instruction *K, const Instruction *J,
+                           bool DoesKMove);
+
+/// Patch the replacement so that it is not more restrictive than the value
+/// being replaced. It assumes that the replacement does not get moved from
+/// its original position.
+void patchReplacementInstruction(Instruction *I, Value *Repl);
+
+// Replace each use of 'From' with 'To', if that use does not belong to basic
+// block where 'From' is defined. Returns the number of replacements made.
+unsigned replaceNonLocalUsesWith(Instruction *From, Value *To);
+
+/// Replace each use of 'From' with 'To' if that use is dominated by
+/// the given edge.  Returns the number of replacements made.
+unsigned replaceDominatedUsesWith(Value *From, Value *To, DominatorTree &DT,
+                                  const BasicBlockEdge &Edge);
+/// Replace each use of 'From' with 'To' if that use is dominated by
+/// the end of the given BasicBlock. Returns the number of replacements made.
+unsigned replaceDominatedUsesWith(Value *From, Value *To, DominatorTree &DT,
+                                  const BasicBlock *BB);
+
+/// Return true if this call calls a gc leaf function.
+///
+/// A leaf function is a function that does not safepoint the thread during its
+/// execution.  During a call or invoke to such a function, the callers stack
+/// does not have to be made parseable.
+///
+/// Most passes can and should ignore this information, and it is only used
+/// during lowering by the GC infrastructure.
+bool callsGCLeafFunction(const CallBase *Call, const TargetLibraryInfo &TLI);
+
+/// Copy a nonnull metadata node to a new load instruction.
+///
+/// This handles mapping it to range metadata if the new load is an integer
+/// load instead of a pointer load.
+void copyNonnullMetadata(const LoadInst &OldLI, MDNode *N, LoadInst &NewLI);
+
+/// Copy a range metadata node to a new load instruction.
+///
+/// This handles mapping it to nonnull metadata if the new load is a pointer
+/// load instead of an integer load and the range doesn't cover null.
+void copyRangeMetadata(const DataLayout &DL, const LoadInst &OldLI, MDNode *N,
+                       LoadInst &NewLI);
+
+/// Remove the debug intrinsic instructions for the given instruction.
+void dropDebugUsers(Instruction &I);
+
+/// Hoist all of the instructions in the \p IfBlock to the dominant block
+/// \p DomBlock, by moving its instructions to the insertion point \p InsertPt.
+///
+/// The moved instructions receive the insertion point debug location values
+/// (DILocations) and their debug intrinsic instructions are removed.
+void hoistAllInstructionsInto(BasicBlock *DomBlock, Instruction *InsertPt,
+                              BasicBlock *BB);
+
+//===----------------------------------------------------------------------===//
+//  Intrinsic pattern matching
+//
+
+/// Try to match a bswap or bitreverse idiom.
+///
+/// If an idiom is matched, an intrinsic call is inserted before \c I. Any added
+/// instructions are returned in \c InsertedInsts. They will all have been added
+/// to a basic block.
+///
+/// A bitreverse idiom normally requires around 2*BW nodes to be searched (where
+/// BW is the bitwidth of the integer type). A bswap idiom requires anywhere up
+/// to BW / 4 nodes to be searched, so is significantly faster.
+///
+/// This function returns true on a successful match or false otherwise.
+bool recognizeBSwapOrBitReverseIdiom(
+    Instruction *I, bool MatchBSwaps, bool MatchBitReversals,
+    SmallVectorImpl<Instruction *> &InsertedInsts);
+
+//===----------------------------------------------------------------------===//
+//  Sanitizer utilities
+//
+
+/// Given a CallInst, check if it calls a string function known to CodeGen,
+/// and mark it with NoBuiltin if so.  To be used by sanitizers that intend
+/// to intercept string functions and want to avoid converting them to target
+/// specific instructions.
+void maybeMarkSanitizerLibraryCallNoBuiltin(CallInst *CI,
+                                            const TargetLibraryInfo *TLI);
+
+//===----------------------------------------------------------------------===//
+//  Transform predicates
+//
+
+/// Given an instruction, is it legal to set operand OpIdx to a non-constant
+/// value?
+bool canReplaceOperandWithVariable(const Instruction *I, unsigned OpIdx);
+
+} // end namespace llvm
+
+#endif // LLVM_TRANSFORMS_UTILS_LOCAL_H