7faf1a0868
This patch adds a pass that provides workarounds for the errata described in GRLIB-TN-0009, GRLIB-TN-0010, GRLIB-TN-0011, GRLIB-TN-0012, and GRLIB-TN-0013, that are applicable to the GR712RC and UT700. The documents are available for download from here: https://www.gaisler.com/index.php/information/app-tech-notes The pass will detect certain sensitive instruction sequences and prevent them from occurring by inserting NOP instruction. Below is an overview of each of the workarounds. A similar implementation is available in GCC. GRLIB-TN-0009: * Insert NOPs to prevent the sequence (stb/sth/st/stf) -> (single non-store/load instruction) -> (any store) * Insert NOPs to prevent the sequence (std/stdf) -> (any store) GRLIB-TN-0010: * Insert a NOP between load instruction and atomic instruction (swap and casa). * Insert a NOP at branch target if load in delay slot and atomic instruction at branch target. * Do not allow functions to begin with atomic instruction. GRLIB-TN-0011: * Insert .p2align 4 before atomic instructions (swap and casa). GRLIB-TN-0012: * Place a NOP at the branch target of an integer branch if it is a floating-point operation or a floating-point branch. GRLIB-TN-0013: * Prevent (div/sqrt) instructions in the delay slot. * Insert NOPs to prevent the sequence (div/sqrt) -> (two or three floating point operations or loads) -> (div/sqrt). * Do not insert NOPs if any of the floating point operations have a dependency on the destination register of the first (div/sqrt). * Do not insert NOPs if one of the floating point operations is a (div/sqrt). * Insert NOPs to prevent (div/sqrt) followed by a branch.
110 lines
3.3 KiB
C++
110 lines
3.3 KiB
C++
//===------- LeonPasses.h - Define passes specific to LEON ----------------===//
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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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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_LIB_TARGET_SPARC_LEON_PASSES_H
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#define LLVM_LIB_TARGET_SPARC_LEON_PASSES_H
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#include "llvm/CodeGen/MachineFunctionPass.h"
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namespace llvm {
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class SparcSubtarget;
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class LLVM_LIBRARY_VISIBILITY LEONMachineFunctionPass
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: public MachineFunctionPass {
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protected:
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const SparcSubtarget *Subtarget = nullptr;
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const int LAST_OPERAND = -1;
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// this vector holds free registers that we allocate in groups for some of the
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// LEON passes
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std::vector<int> UsedRegisters;
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protected:
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LEONMachineFunctionPass(char &ID);
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void clearUsedRegisterList() { UsedRegisters.clear(); }
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void markRegisterUsed(int registerIndex) {
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UsedRegisters.push_back(registerIndex);
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}
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};
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class LLVM_LIBRARY_VISIBILITY ErrataWorkaround : public MachineFunctionPass {
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protected:
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const SparcSubtarget *ST;
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const TargetInstrInfo *TII;
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const TargetRegisterInfo *TRI;
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bool checkSeqTN0009A(MachineBasicBlock::iterator I);
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bool checkSeqTN0009B(MachineBasicBlock::iterator I);
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bool checkSeqTN0010First(MachineBasicBlock &MBB);
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bool checkSeqTN0010(MachineBasicBlock::iterator I);
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bool checkSeqTN0012(MachineBasicBlock::iterator I);
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bool checkSeqTN0013(MachineBasicBlock::iterator I);
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bool moveNext(MachineBasicBlock::iterator &I);
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bool isFloat(MachineBasicBlock::iterator I);
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bool isDivSqrt(MachineBasicBlock::iterator I);
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void insertNop(MachineBasicBlock::iterator I);
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public:
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static char ID;
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ErrataWorkaround();
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bool runOnMachineFunction(MachineFunction &MF) override;
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StringRef getPassName() const override { return "Errata workaround pass"; };
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};
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class LLVM_LIBRARY_VISIBILITY InsertNOPLoad : public LEONMachineFunctionPass {
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public:
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static char ID;
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InsertNOPLoad();
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bool runOnMachineFunction(MachineFunction &MF) override;
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StringRef getPassName() const override {
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return "InsertNOPLoad: Erratum Fix LBR35: insert a NOP instruction after "
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"every single-cycle load instruction when the next instruction is "
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"another load/store instruction";
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}
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};
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class LLVM_LIBRARY_VISIBILITY DetectRoundChange
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: public LEONMachineFunctionPass {
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public:
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static char ID;
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DetectRoundChange();
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bool runOnMachineFunction(MachineFunction &MF) override;
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StringRef getPassName() const override {
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return "DetectRoundChange: Leon erratum detection: detect any rounding "
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"mode change request: use only the round-to-nearest rounding mode";
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}
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};
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class LLVM_LIBRARY_VISIBILITY FixAllFDIVSQRT : public LEONMachineFunctionPass {
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public:
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static char ID;
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FixAllFDIVSQRT();
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bool runOnMachineFunction(MachineFunction &MF) override;
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StringRef getPassName() const override {
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return "FixAllFDIVSQRT: Erratum Fix LBR34: fix FDIVS/FDIVD/FSQRTS/FSQRTD "
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"instructions with NOPs and floating-point store";
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}
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};
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} // namespace llvm
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#endif // LLVM_LIB_TARGET_SPARC_LEON_PASSES_H
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