LCOV - code coverage report
Current view: top level - lib/Target/ARM - ARMComputeBlockSize.cpp (source / functions) Hit Total Coverage
Test: llvm-toolchain.info Lines: 23 23 100.0 %
Date: 2017-09-14 15:23:50 Functions: 2 2 100.0 %
Legend: Lines: hit not hit

          Line data    Source code
       1             : //===--- ARMComputeBlockSize.cpp - Compute machine block sizes ------------===//
       2             : //
       3             : //                     The LLVM Compiler Infrastructure
       4             : //
       5             : // This file is distributed under the University of Illinois Open Source
       6             : // License. See LICENSE.TXT for details.
       7             : //
       8             : //===----------------------------------------------------------------------===//
       9             : 
      10             : #include "ARM.h"
      11             : #include "ARMBaseInstrInfo.h"
      12             : #include "ARMBasicBlockInfo.h"
      13             : #include "ARMMachineFunctionInfo.h"
      14             : #include "llvm/CodeGen/MachineBasicBlock.h"
      15             : #include "llvm/CodeGen/MachineFunction.h"
      16             : #include "llvm/CodeGen/MachineInstr.h"
      17             : #include "llvm/Target/TargetSubtargetInfo.h"
      18             : #include <vector>
      19             : 
      20             : using namespace llvm;
      21             : 
      22             : namespace llvm {
      23             : 
      24             : // mayOptimizeThumb2Instruction - Returns true if optimizeThumb2Instructions
      25             : // below may shrink MI.
      26             : static bool
      27             : mayOptimizeThumb2Instruction(const MachineInstr *MI) {
      28      116518 :   switch(MI->getOpcode()) {
      29             :     // optimizeThumb2Instructions.
      30             :     case ARM::t2LEApcrel:
      31             :     case ARM::t2LDRpci:
      32             :     // optimizeThumb2Branches.
      33             :     case ARM::t2B:
      34             :     case ARM::t2Bcc:
      35             :     case ARM::tBcc:
      36             :     // optimizeThumb2JumpTables.
      37             :     case ARM::t2BR_JT:
      38             :       return true;
      39             :   }
      40             :   return false;
      41             : }
      42             : 
      43       17680 : void computeBlockSize(MachineFunction *MF, MachineBasicBlock *MBB,
      44             :                       BasicBlockInfo &BBI) {
      45             :   const ARMBaseInstrInfo *TII =
      46       17680 :     static_cast<const ARMBaseInstrInfo *>(MF->getSubtarget().getInstrInfo());
      47       17680 :   bool isThumb = MF->getInfo<ARMFunctionInfo>()->isThumbFunction();
      48       17680 :   BBI.Size = 0;
      49       17680 :   BBI.Unalign = 0;
      50       17680 :   BBI.PostAlign = 0;
      51             : 
      52      501852 :   for (MachineInstr &I : *MBB) {
      53      215566 :     BBI.Size += TII->getInstSizeInBytes(I);
      54             :     // For inline asm, getInstSizeInBytes returns a conservative estimate.
      55             :     // The actual size may be smaller, but still a multiple of the instr size.
      56      215566 :     if (I.isInlineAsm())
      57       19105 :       BBI.Unalign = isThumb ? 1 : 2;
      58             :     // Also consider instructions that may be shrunk later.
      59      199040 :     else if (isThumb && mayOptimizeThumb2Instruction(&I))
      60        2579 :       BBI.Unalign = 1;
      61             :   }
      62             : 
      63             :   // tBR_JTr contains a .align 2 directive.
      64       52744 :   if (!MBB->empty() && MBB->back().getOpcode() == ARM::tBR_JTr) {
      65          18 :     BBI.PostAlign = 2;
      66          18 :     MBB->getParent()->ensureAlignment(2);
      67             :   }
      68       17680 : }
      69             : 
      70       11978 : std::vector<BasicBlockInfo> computeAllBlockSizes(MachineFunction *MF) {
      71       11978 :   std::vector<BasicBlockInfo> BBInfo;
      72       11978 :   BBInfo.resize(MF->getNumBlockIDs());
      73             : 
      74       53565 :   for (MachineBasicBlock &MBB : *MF)
      75       35262 :     computeBlockSize(MF, &MBB, BBInfo[MBB.getNumber()]);
      76             : 
      77       11978 :   return BBInfo;
      78             : }
      79             : 
      80             : } // end namespace llvm

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