llvm-6502/lib/Target/PIC16/PIC16Passes/PIC16Cloner.cpp
2010-04-15 01:51:59 +00:00

300 lines
9.9 KiB
C++

//===-- PIC16Cloner.cpp - PIC16 LLVM Cloner for shared functions -*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains code to clone all functions that are shared between
// the main line code (ML) and interrupt line code (IL). It clones all such
// shared functions and their automatic global vars by adding the .IL suffix.
//
// This pass is supposed to be run on the linked .bc module.
// It traveses the module call graph twice. Once starting from the main function
// and marking each reached function as "ML". Again, starting from the ISR
// and cloning any reachable function that was marked as "ML". After cloning
// the function, it remaps all the call sites in IL functions to call the
// cloned functions.
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/CallGraph.h"
#include "llvm/Pass.h"
#include "llvm/Module.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/Utils/Cloning.h"
#include "PIC16Cloner.h"
#include "../PIC16ABINames.h"
#include <vector>
using namespace llvm;
using std::vector;
using std::string;
using std::map;
namespace llvm {
char PIC16Cloner::ID = 0;
ModulePass *createPIC16ClonerPass() { return new PIC16Cloner(); }
}
// We currently intend to run these passes in opt, which does not have any
// diagnostic support. So use these functions for now. In future
// we will probably write our own driver tool.
//
void PIC16Cloner::reportError(string ErrorString) {
errs() << "ERROR : " << ErrorString << "\n";
exit(1);
}
void PIC16Cloner::
reportError (string ErrorString, vector<string> &Values) {
unsigned ValCount = Values.size();
string TargetString;
for (unsigned i=0; i<ValCount; ++i) {
TargetString = "%";
TargetString += ((char)i + '0');
ErrorString.replace(ErrorString.find(TargetString), TargetString.length(),
Values[i]);
}
errs() << "ERROR : " << ErrorString << "\n";
exit(1);
}
// Entry point
//
bool PIC16Cloner::runOnModule(Module &M) {
CallGraph &CG = getAnalysis<CallGraph>();
// Search for the "main" and "ISR" functions.
CallGraphNode *mainCGN = NULL, *isrCGN = NULL;
for (CallGraph::iterator it = CG.begin() ; it != CG.end(); it++)
{
// External calling node doesn't have any function associated with it.
if (! it->first)
continue;
if (it->first->getName().str() == "main") {
mainCGN = it->second;
}
if (PAN::isISR(it->first->getSection())) {
isrCGN = it->second;
}
// Don't search further if we've found both.
if (mainCGN && isrCGN)
break;
}
// We have nothing to do if any of the main or ISR is missing.
if (! mainCGN || ! isrCGN) return false;
// Time for some diagnostics.
// See if the main itself is interrupt function then report an error.
if (PAN::isISR(mainCGN->getFunction()->getSection())) {
reportError("Function 'main' can't be interrupt function");
}
// Mark all reachable functions from main as ML.
markCallGraph(mainCGN, "ML");
// And then all the functions reachable from ISR will be cloned.
cloneSharedFunctions(isrCGN);
return true;
}
// Mark all reachable functions from the given node, with the given mark.
//
void PIC16Cloner::markCallGraph(CallGraphNode *CGN, string StringMark) {
// Mark the top node first.
Function *thisF = CGN->getFunction();
thisF->setSection(StringMark);
// Mark all the called functions
for(CallGraphNode::iterator cgn_it = CGN->begin();
cgn_it != CGN->end(); ++cgn_it) {
Function *CalledF = cgn_it->second->getFunction();
// If calling an external function then CallGraphNode
// will not be associated with any function.
if (! CalledF)
continue;
// Issue diagnostic if interrupt function is being called.
if (PAN::isISR(CalledF->getSection())) {
vector<string> Values;
Values.push_back(CalledF->getName().str());
reportError("Interrupt function (%0) can't be called", Values);
}
// Has already been mark
if (CalledF->getSection().find(StringMark) != string::npos) {
// Should we do anything here?
} else {
// Mark now
CalledF->setSection(StringMark);
}
// Before going any further mark all the called function by current
// function.
markCallGraph(cgn_it->second ,StringMark);
} // end of loop of all called functions.
}
// For PIC16, automatic variables of a function are emitted as globals.
// Clone the auto variables of a function and put them in ValueMap,
// this ValueMap will be used while
// Cloning the code of function itself.
//
void PIC16Cloner::CloneAutos(Function *F) {
// We'll need to update module's globals list as well. So keep a reference
// handy.
Module *M = F->getParent();
Module::GlobalListType &Globals = M->getGlobalList();
// Clear the leftovers in ValueMap by any previous cloning.
ValueMap.clear();
// Find the auto globls for this function and clone them, and put them
// in ValueMap.
std::string FnName = F->getName().str();
std::string VarName, ClonedVarName;
for (Module::global_iterator I = M->global_begin(), E = M->global_end();
I != E; ++I) {
VarName = I->getName().str();
if (PAN::isLocalToFunc(FnName, VarName)) {
// Auto variable for current function found. Clone it.
const GlobalVariable *GV = I;
const Type *InitTy = GV->getInitializer()->getType();
GlobalVariable *ClonedGV =
new GlobalVariable(InitTy, false, GV->getLinkage(),
GV->getInitializer());
ClonedGV->setName(PAN::getCloneVarName(FnName, VarName));
// Add these new globals to module's globals list.
Globals.push_back(ClonedGV);
// Update ValueMap.
ValueMap[GV] = ClonedGV;
}
}
}
// Clone all functions that are reachable from ISR and are already
// marked as ML.
//
void PIC16Cloner::cloneSharedFunctions(CallGraphNode *CGN) {
// Check all the called functions from ISR.
for(CallGraphNode::iterator cgn_it = CGN->begin();
cgn_it != CGN->end(); ++cgn_it) {
Function *CalledF = cgn_it->second->getFunction();
// If calling an external function then CallGraphNode
// will not be associated with any function.
if (!CalledF)
continue;
// Issue diagnostic if interrupt function is being called.
if (PAN::isISR(CalledF->getSection())) {
vector<string> Values;
Values.push_back(CalledF->getName().str());
reportError("Interrupt function (%0) can't be called", Values);
}
if (CalledF->getSection().find("ML") != string::npos) {
// Function is alternatively marked. It should be a shared one.
// Create IL copy. Passing called function as first argument
// and the caller as the second argument.
// Before making IL copy, first ensure that this function has a
// body. If the function does have a body. It can't be cloned.
// Such a case may occur when the function has been declarated
// in the C source code but its body exists in assembly file.
if (!CalledF->isDeclaration()) {
Function *cf = cloneFunction(CalledF);
remapAllSites(CGN->getFunction(), CalledF, cf);
} else {
// It is called only from ISR. Still mark it as we need this info
// in code gen while calling intrinsics.Function is not marked.
CalledF->setSection("IL");
}
}
// Before going any further clone all the shared function reachaable
// by current function.
cloneSharedFunctions(cgn_it->second);
} // end of loop of all called functions.
}
// Clone the given function and return it.
// Note: it uses the ValueMap member of the class, which is already populated
// by cloneAutos by the time we reach here.
// FIXME: Should we just pass ValueMap's ref as a parameter here? rather
// than keeping the ValueMap as a member.
Function *
PIC16Cloner::cloneFunction(Function *OrgF) {
Function *ClonedF;
// See if we already cloned it. Return that.
cloned_map_iterator cm_it = ClonedFunctionMap.find(OrgF);
if(cm_it != ClonedFunctionMap.end()) {
ClonedF = cm_it->second;
return ClonedF;
}
// Clone does not exist.
// First clone the autos, and populate ValueMap.
CloneAutos(OrgF);
// Now create the clone.
ClonedF = CloneFunction(OrgF, ValueMap);
// The new function should be for interrupt line. Therefore should have
// the name suffixed with IL and section attribute marked with IL.
ClonedF->setName(PAN::getCloneFnName(OrgF->getName()));
ClonedF->setSection("IL");
// Add the newly created function to the module.
OrgF->getParent()->getFunctionList().push_back(ClonedF);
// Update the ClonedFunctionMap to record this cloning activity.
ClonedFunctionMap[OrgF] = ClonedF;
return ClonedF;
}
// Remap the call sites of shared functions, that are in IL.
// Change the IL call site of a shared function to its clone.
//
void PIC16Cloner::
remapAllSites(Function *Caller, Function *OrgF, Function *Clone) {
// First find the caller to update. If the caller itself is cloned
// then use the cloned caller. Otherwise use it.
cloned_map_iterator cm_it = ClonedFunctionMap.find(Caller);
if (cm_it != ClonedFunctionMap.end())
Caller = cm_it->second;
// For the lack of a better call site finding mechanism, iterate over
// all insns to find the uses of original fn.
for (Function::iterator BI = Caller->begin(); BI != Caller->end(); ++BI) {
BasicBlock &BB = *BI;
for (BasicBlock::iterator II = BB.begin(); II != BB.end(); ++II) {
if (II->getNumOperands() > 0 && II->getOperand(0) == OrgF)
II->setOperand(0, Clone);
}
}
}