Moving these files from Code/PreSelection to here.

Original logs for PreSelection.cpp:

  revision 1.2
  date: 2002/09/17 23:50:32;  author: lattner;  state: Exp;  lines: +1 -3
  Don't put default parameter values into .cpp files, it breaks 3.x compilers

  revision 1.1
  date: 2002/09/16 15:31:13;  author: vadve;  state: Exp;
  New preselection pass that specializes LLVM code for a target machine,
  while remaining in legal portable LLVM form and preserving type
  information and type safety.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@3838 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Vikram S. Adve 2002-09-20 00:29:28 +00:00
parent 3aaff7eebd
commit abf055c698
2 changed files with 294 additions and 0 deletions

View File

@ -0,0 +1,8 @@
LEVEL = ../../..
DIRS =
LIBRARYNAME = preopts
include $(LEVEL)/Makefile.common

View File

@ -0,0 +1,286 @@
//===- PreSelection.cpp - Specialize LLVM code for target machine ---------===//
//
// This file defines the PreSelection pass which specializes LLVM code for a
// target machine, while remaining in legal portable LLVM form and
// preserving type information and type safety. This is meant to enable
// dataflow optimizations on target-specific operations such as accesses to
// constants, globals, and array indexing.
//
//===----------------------------------------------------------------------===//
#include "llvm/CodeGen/PreSelection.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/MachineInstrInfo.h"
#include "llvm/Transforms/Scalar.h"
#include "llvm/Support/InstVisitor.h"
#include "llvm/Module.h"
#include "llvm/Constants.h"
#include "llvm/iMemory.h"
#include "llvm/iPHINode.h"
#include "llvm/iOther.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Pass.h"
#include "llvm/Annotation.h"
#include "Support/CommandLine.h"
#include "Support/NonCopyable.h"
using std::map;
using std::cerr;
namespace {
//===--------------------------------------------------------------------===//
// SelectDebugLevel - Allow command line control over debugging.
//
enum PreSelectDebugLevel_t {
PreSelect_NoDebugInfo,
PreSelect_PrintOutput,
};
// Enable Debug Options to be specified on the command line
cl::opt<PreSelectDebugLevel_t>
PreSelectDebugLevel("dpreselect", cl::Hidden,
cl::desc("debug information for target-dependent pre-selection"),
cl::values(
clEnumValN(PreSelect_NoDebugInfo, "n", "disable debug output (default)"),
clEnumValN(PreSelect_PrintOutput, "y", "print generated machine code"),
/* default level = */ PreSelect_NoDebugInfo));
//===--------------------------------------------------------------------===//
// class ConstantPoolForModule:
//
// The pool of constants that must be emitted for a module.
// This is a single pool for the entire module and is shared by
// all invocations of the PreSelection pass for this module by putting
// this as as annotation on the Module object.
// A single GlobalVariable is created for each constant in the pool
// representing the memory for that constant.
//
static AnnotationID CPFM_AID(
AnnotationManager::getID("CodeGen::ConstantPoolForModule"));
class ConstantPoolForModule: private Annotation, public NonCopyable {
Module* myModule;
std::map<const Constant*, GlobalVariable*> gvars;
std::map<const Constant*, GlobalVariable*> origGVars;
ConstantPoolForModule(Module* M); // called only by annotation builder
ConstantPoolForModule(); // do not implement
public:
static ConstantPoolForModule& get(Module* M) {
ConstantPoolForModule* cpool =
(ConstantPoolForModule*) M->getAnnotation(CPFM_AID);
if (cpool == NULL) // create a new annotation and add it to the Module
M->addAnnotation(cpool = new ConstantPoolForModule(M));
return *cpool;
}
GlobalVariable* getGlobalForConstant(Constant* CV) {
std::map<const Constant*, GlobalVariable*>::iterator I = gvars.find(CV);
if (I != gvars.end())
return I->second; // global exists so return it
return addToConstantPool(CV); // create a new global and return it
}
GlobalVariable* addToConstantPool(Constant* CV) {
GlobalVariable*& GV = gvars[CV]; // handle to global var entry in map
if (GV == NULL)
{ // check if a global constant already existed; otherwise create one
std::map<const Constant*, GlobalVariable*>::iterator PI =
origGVars.find(CV);
if (PI != origGVars.end())
GV = PI->second; // put in map
else
{
GV = new GlobalVariable(CV->getType(), true,true,CV); //put in map
myModule->getGlobalList().push_back(GV); // GV owned by module now
}
}
return GV;
}
};
/* ctor */
ConstantPoolForModule::ConstantPoolForModule(Module* M)
: Annotation(CPFM_AID), myModule(M)
{
// Build reverse map for pre-existing global constants so we can find them
for (Module::giterator GI = M->gbegin(), GE = M->gend(); GI != GE; ++GI)
if (GI->hasInitializer() && GI->isConstant())
origGVars[GI->getInitializer()] = GI;
}
//===--------------------------------------------------------------------===//
// PreSelection Pass - Specialize LLVM code for the current target machine.
// This was and will be a basicblock pass, but make it a FunctionPass until
// BasicBlockPass ::doFinalization(Function&) is available.
//
class PreSelection : public BasicBlockPass, public InstVisitor<PreSelection>
{
const TargetMachine &target;
Function* function;
GetElementPtrInst* getGlobalAddr(Value* ptr, Instruction* insertBefore = 0);
GlobalVariable* getGlobalForConstant(Constant* CV) {
Module* M = function->getParent();
return ConstantPoolForModule::get(M).getGlobalForConstant(CV);
}
public:
PreSelection (const TargetMachine &T): target(T), function(NULL) {}
// runOnBasicBlock - apply this pass to each BB
bool runOnBasicBlock(BasicBlock &BB) {
function = BB.getParent();
this->visit(BB);
return true;
}
bool doFinalization(Function &F) {
if (PreSelectDebugLevel >= PreSelect_PrintOutput)
cerr << "\n\n*** LLVM code after pre-selection for function "
<< F.getName() << ":\n\n" << F;
return false;
}
// These methods do the actual work of specializing code
void visitInstruction(Instruction &I); // common work for every instr.
void visitGetElementPtrInst(GetElementPtrInst &I);
void visitLoadInst(LoadInst &I);
void visitStoreInst(StoreInst &I);
// Helper functions for visiting operands of every instruction
void visitOperands(Instruction &I); // work on all operands of instr.
void visitOneOperand(Instruction &I, Constant* CV, unsigned opNum,
Instruction& insertBefore); // iworks on one operand
};
} // end anonymous namespace
// Register the pass...
static RegisterOpt<PreSelection> X("preselect",
"Specialize LLVM code for a target machine",
createPreSelectionPass);
// PreSelection::getGlobalAddr: Put address of a global into a v. register.
GetElementPtrInst*
PreSelection::getGlobalAddr(Value* ptr, Instruction* insertBefore)
{
return (isa<GlobalValue>(ptr))
? new GetElementPtrInst(ptr,
std::vector<Value*>(1, ConstantSInt::get(Type::LongTy, 0U)),
"addrOfGlobal", insertBefore)
: NULL;
}
//------------------------------------------------------------------------------
// Instruction visitor methods to perform instruction-specific operations
//------------------------------------------------------------------------------
// Common work for *all* instructions. This needs to be called explicitly
// by other visit<InstructionType> functions.
inline void
PreSelection::visitInstruction(Instruction &I)
{
visitOperands(I); // Perform operand transformations
}
// GetElementPtr instructions: check if pointer is a global
void
PreSelection::visitGetElementPtrInst(GetElementPtrInst &I)
{
// Check for a global and put its address into a register before this instr
if (GetElementPtrInst* gep = getGlobalAddr(I.getPointerOperand(), &I))
I.setOperand(I.getPointerOperandIndex(), gep); // replace pointer operand
// Decompose multidimensional array references
DecomposeArrayRef(&I);
// Perform other transformations common to all instructions
visitInstruction(I);
}
// Load instructions: check if pointer is a global
void
PreSelection::visitLoadInst(LoadInst &I)
{
// Check for a global and put its address into a register before this instr
if (GetElementPtrInst* gep = getGlobalAddr(I.getPointerOperand(), &I))
I.setOperand(I.getPointerOperandIndex(), gep); // replace pointer operand
// Perform other transformations common to all instructions
visitInstruction(I);
}
// Store instructions: check if pointer is a global
void
PreSelection::visitStoreInst(StoreInst &I)
{
// Check for a global and put its address into a register before this instr
if (GetElementPtrInst* gep = getGlobalAddr(I.getPointerOperand(), &I))
I.setOperand(I.getPointerOperandIndex(), gep); // replace pointer operand
// Perform other transformations common to all instructions
visitInstruction(I);
}
// visitOperands() transforms individual operands of all instructions:
// -- Load "large" int constants into a virtual register. What is large
// depends on the type of instruction and on the target architecture.
// -- For any constants that cannot be put in an immediate field,
// load address into virtual register first, and then load the constant.
//
void
PreSelection::visitOperands(Instruction &I)
{
// For any instruction other than PHI, copies go just before the instr.
// For a PHI, operand copies must be before the terminator of the
// appropriate predecessor basic block. Remaining logic is simple
// so just handle PHIs and other instructions separately.
//
if (PHINode* phi = dyn_cast<PHINode>(&I))
{
for (unsigned i=0, N=phi->getNumIncomingValues(); i < N; ++i)
if (Constant* CV = dyn_cast<Constant>(phi->getIncomingValue(i)))
this->visitOneOperand(I, CV, phi->getOperandNumForIncomingValue(i),
* phi->getIncomingBlock(i)->getTerminator());
}
else
for (unsigned i=0, N=I.getNumOperands(); i < N; ++i)
if (Constant* CV = dyn_cast<Constant>(I.getOperand(i)))
this->visitOneOperand(I, CV, i, I);
}
void
PreSelection::visitOneOperand(Instruction &I, Constant* CV, unsigned opNum,
Instruction& insertBefore)
{
if (target.getInstrInfo().ConstantTypeMustBeLoaded(CV))
{ // load address of constant into a register, then load the constant
GetElementPtrInst* gep = getGlobalAddr(getGlobalForConstant(CV),
&insertBefore);
LoadInst* ldI = new LoadInst(gep, "loadConst", &insertBefore);
I.setOperand(opNum, ldI); // replace operand with copy in v.reg.
}
else if (target.getInstrInfo().ConstantMayNotFitInImmedField(CV, &I))
{ // put the constant into a virtual register using a cast
CastInst* castI = new CastInst(CV, CV->getType(), "copyConst",
&insertBefore);
I.setOperand(opNum, castI); // replace operand with copy in v.reg.
}
}
//===----------------------------------------------------------------------===//
// createPreSelectionPass - Public entrypoint for pre-selection pass
// and this file as a whole...
//
Pass*
createPreSelectionPass(TargetMachine &T)
{
return new PreSelection(T);
}