This class allows to keep track on instructions with implicit control flow. More...
#include "llvm/Analysis/InstructionPrecedenceTracking.h"
Public Member Functions | |
| const Instruction * | getFirstICFI (const BasicBlock *BB) |
| Returns the topmost instruction with implicit control flow from the given basic block. | |
| bool | hasICF (const BasicBlock *BB) |
| Returns true if at least one instruction from the given basic block has implicit control flow. | |
| bool | isDominatedByICFIFromSameBlock (const Instruction *Insn) |
| Returns true if the first ICFI of Insn's block exists and dominates Insn. | |
| bool | isSpecialInstruction (const Instruction *Insn) const override |
A predicate that defines whether or not the instruction Insn is considered special and needs to be tracked. | |
 Public Member Functions inherited from llvm::InstructionPrecedenceTracking | |
| void | insertInstructionTo (const Instruction *Inst, const BasicBlock *BB) |
Notifies this tracking that we are going to insert a new instruction Inst to the basic block BB. | |
| void | removeInstruction (const Instruction *Inst) |
Notifies this tracking that we are going to remove the instruction Inst It makes all necessary updates to internal caches to keep them consistent. | |
| void | removeUsersOf (const Instruction *Inst) |
Notifies this tracking that we are going to replace all uses of Inst. | |
| void | clear () |
| Invalidates all information from this tracking. | |
Additional Inherited Members | |
| Protected Member Functions inherited from llvm::InstructionPrecedenceTracking | |
| const Instruction * | getFirstSpecialInstruction (const BasicBlock *BB) |
Returns the topmost special instruction from the block BB. | |
| bool | hasSpecialInstructions (const BasicBlock *BB) |
Returns true iff at least one instruction from the basic block BB is special. | |
| bool | isPreceededBySpecialInstruction (const Instruction *Insn) |
Returns true iff the first special instruction of Insn's block exists and dominates Insn. | |
| virtual bool | isSpecialInstruction (const Instruction *Insn) const =0 |
A predicate that defines whether or not the instruction Insn is considered special and needs to be tracked. | |
| virtual | ~InstructionPrecedenceTracking ()=default |
Detailed Description
This class allows to keep track on instructions with implicit control flow.
These are instructions that may not pass execution to their successors. For example, throwing calls and guards do not always do this. If we need to know for sure that some instruction is guaranteed to execute if the given block is reached, then we need to make sure that there is no implicit control flow instruction (ICFI) preceding it. For example, this check is required if we perform PRE moving non-speculable instruction to other place.
Definition at line 99 of file InstructionPrecedenceTracking.h.
Member Function Documentation
◆ getFirstICFI()
|
inline |
Returns the topmost instruction with implicit control flow from the given basic block.
Returns nullptr if there is no such instructions in the block.
Definition at line 103 of file InstructionPrecedenceTracking.h.
References llvm::InstructionPrecedenceTracking::getFirstSpecialInstruction().
◆ hasICF()
|
inline |
Returns true if at least one instruction from the given basic block has implicit control flow.
Definition at line 109 of file InstructionPrecedenceTracking.h.
References llvm::InstructionPrecedenceTracking::hasSpecialInstructions().
Referenced by llvm::ICFLoopSafetyInfo::blockMayThrow(), and llvm::ICFLoopSafetyInfo::computeLoopSafetyInfo().
◆ isDominatedByICFIFromSameBlock()
|
inline |
Returns true if the first ICFI of Insn's block exists and dominates Insn.
Definition at line 114 of file InstructionPrecedenceTracking.h.
References Insn, and llvm::InstructionPrecedenceTracking::isPreceededBySpecialInstruction().
Referenced by llvm::ICFLoopSafetyInfo::isGuaranteedToExecute().
◆ isSpecialInstruction()
|
overridevirtual |
A predicate that defines whether or not the instruction Insn is considered special and needs to be tracked.
Implementing this method in children classes allows to implement tracking of implicit control flow, memory writing instructions or any other kinds of instructions we might be interested in.
Implements llvm::InstructionPrecedenceTracking.
Definition at line 137 of file InstructionPrecedenceTracking.cpp.
References Insn, and llvm::isGuaranteedToTransferExecutionToSuccessor().
The documentation for this class was generated from the following files:
- include/llvm/Analysis/InstructionPrecedenceTracking.h
- lib/Analysis/InstructionPrecedenceTracking.cpp
