llvm/lib/Target/ARM/ARMComputeBlockSize.cpp
David Blaikie e3a9b4ce3a Fix a bunch more layering of CodeGen headers that are in Target
All these headers already depend on CodeGen headers so moving them into
CodeGen fixes the layering (since CodeGen depends on Target, not the
other way around).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@318490 91177308-0d34-0410-b5e6-96231b3b80d8
2017-11-17 01:07:10 +00:00

81 lines
2.4 KiB
C++

//===--- ARMComputeBlockSize.cpp - Compute machine block sizes ------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "ARM.h"
#include "ARMBaseInstrInfo.h"
#include "ARMBasicBlockInfo.h"
#include "ARMMachineFunctionInfo.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/TargetSubtargetInfo.h"
#include <vector>
using namespace llvm;
namespace llvm {
// mayOptimizeThumb2Instruction - Returns true if optimizeThumb2Instructions
// below may shrink MI.
static bool
mayOptimizeThumb2Instruction(const MachineInstr *MI) {
switch(MI->getOpcode()) {
// optimizeThumb2Instructions.
case ARM::t2LEApcrel:
case ARM::t2LDRpci:
// optimizeThumb2Branches.
case ARM::t2B:
case ARM::t2Bcc:
case ARM::tBcc:
// optimizeThumb2JumpTables.
case ARM::t2BR_JT:
return true;
}
return false;
}
void computeBlockSize(MachineFunction *MF, MachineBasicBlock *MBB,
BasicBlockInfo &BBI) {
const ARMBaseInstrInfo *TII =
static_cast<const ARMBaseInstrInfo *>(MF->getSubtarget().getInstrInfo());
bool isThumb = MF->getInfo<ARMFunctionInfo>()->isThumbFunction();
BBI.Size = 0;
BBI.Unalign = 0;
BBI.PostAlign = 0;
for (MachineInstr &I : *MBB) {
BBI.Size += TII->getInstSizeInBytes(I);
// For inline asm, getInstSizeInBytes returns a conservative estimate.
// The actual size may be smaller, but still a multiple of the instr size.
if (I.isInlineAsm())
BBI.Unalign = isThumb ? 1 : 2;
// Also consider instructions that may be shrunk later.
else if (isThumb && mayOptimizeThumb2Instruction(&I))
BBI.Unalign = 1;
}
// tBR_JTr contains a .align 2 directive.
if (!MBB->empty() && MBB->back().getOpcode() == ARM::tBR_JTr) {
BBI.PostAlign = 2;
MBB->getParent()->ensureAlignment(2);
}
}
std::vector<BasicBlockInfo> computeAllBlockSizes(MachineFunction *MF) {
std::vector<BasicBlockInfo> BBInfo;
BBInfo.resize(MF->getNumBlockIDs());
for (MachineBasicBlock &MBB : *MF)
computeBlockSize(MF, &MBB, BBInfo[MBB.getNumber()]);
return BBInfo;
}
} // end namespace llvm