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llvm-mirror/lib/CodeGen/RegUsageInfoPropagate.cpp
Mehdi Amini 4cc3acc6c7 Interprocedural Register Allocation (IPRA): add a Transformation Pass
Adds a MachineFunctionPass that scans the body to find calls, and
update the register mask with the one saved by the
RegUsageInfoCollector analysis in PhysicalRegisterUsageInfo.

Patch by Vivek Pandya <vivekvpandya@gmail.com>

Differential Revision: http://reviews.llvm.org/D21180

llvm-svn: 272414
2016-06-10 18:37:21 +00:00

132 lines
4.3 KiB
C++

//=--- RegUsageInfoPropagate.cpp - Register Usage Informartion Propagation --=//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
///
/// This pass is required to take advantage of the interprocedural register
/// allocation infrastructure.
///
/// This pass iterates through MachineInstrs in a given MachineFunction and at
/// each callsite queries RegisterUsageInfo for RegMask (calculated based on
/// actual register allocation) of the callee function, if the RegMask detail
/// is available then this pass will update the RegMask of the call instruction.
/// This updated RegMask will be used by the register allocator while allocating
/// the current MachineFunction.
///
//===----------------------------------------------------------------------===//
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/CodeGen/RegisterUsageInfo.h"
#include "llvm/IR/Module.h"
#include "llvm/PassAnalysisSupport.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetMachine.h"
#include <map>
#include <string>
namespace llvm {
void initializeRegUsageInfoPropagationPassPass(PassRegistry &);
}
using namespace llvm;
#define DEBUG_TYPE "ip-regalloc"
#define RUIP_NAME "Register Usage Information Propagation"
namespace {
class RegUsageInfoPropagationPass : public MachineFunctionPass {
public:
RegUsageInfoPropagationPass() : MachineFunctionPass(ID) {
PassRegistry &Registry = *PassRegistry::getPassRegistry();
initializeRegUsageInfoPropagationPassPass(Registry);
}
const char *getPassName() const override { return RUIP_NAME; }
bool runOnMachineFunction(MachineFunction &MF) override;
void getAnalysisUsage(AnalysisUsage &AU) const override;
static char ID;
private:
static void setRegMask(MachineInstr &MI, const uint32_t *RegMask) {
for (MachineOperand &MO : MI.operands()) {
if (MO.isRegMask())
MO.setRegMask(RegMask);
}
}
};
} // end of anonymous namespace
char RegUsageInfoPropagationPass::ID = 0;
INITIALIZE_PASS_BEGIN(RegUsageInfoPropagationPass, "reg-usage-propagation",
RUIP_NAME, false, false)
INITIALIZE_PASS_DEPENDENCY(PhysicalRegisterUsageInfo)
INITIALIZE_PASS_END(RegUsageInfoPropagationPass, "reg-usage-propagation",
RUIP_NAME, false, false)
FunctionPass *llvm::createRegUsageInfoPropPass() {
return new RegUsageInfoPropagationPass();
}
void RegUsageInfoPropagationPass::getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<PhysicalRegisterUsageInfo>();
AU.setPreservesAll();
MachineFunctionPass::getAnalysisUsage(AU);
}
bool RegUsageInfoPropagationPass::runOnMachineFunction(MachineFunction &MF) {
const Module *M = MF.getFunction()->getParent();
PhysicalRegisterUsageInfo *PRUI = &getAnalysis<PhysicalRegisterUsageInfo>();
DEBUG(dbgs() << " ++++++++++++++++++++ " << getPassName()
<< " ++++++++++++++++++++ \n");
DEBUG(dbgs() << "MachineFunction : " << MF.getName() << "\n");
bool Changed = false;
for (MachineBasicBlock &MBB : MF) {
for (MachineInstr &MI : MBB) {
if (!MI.isCall())
continue;
DEBUG(dbgs()
<< "Call Instruction Before Register Usage Info Propagation : \n");
DEBUG(dbgs() << MI << "\n");
auto UpdateRegMask = [&](const Function *F) {
const auto *RegMask = PRUI->getRegUsageInfo(F);
if (!RegMask)
return;
setRegMask(MI, &(*RegMask)[0]);
Changed = true;
};
MachineOperand &Operand = MI.getOperand(0);
if (Operand.isGlobal())
UpdateRegMask(cast<Function>(Operand.getGlobal()));
else if (Operand.isSymbol())
UpdateRegMask(M->getFunction(Operand.getSymbolName()));
DEBUG(dbgs()
<< "Call Instruction After Register Usage Info Propagation : \n");
DEBUG(dbgs() << MI << "\n");
}
}
DEBUG(dbgs() << " +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++"
"++++++ \n");
return Changed;
}