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//===-- PIC16Overlay.cpp - Implementation for PIC16 Frame Overlay===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains the PIC16 Frame Overlay implementation.
//
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/CallGraph.h"
#include "llvm/Pass.h"
#include "llvm/Module.h"
#include "llvm/Instructions.h"
#include "llvm/Value.h"
#include "PIC16Overlay.h"
#include "llvm/Function.h"
#include <cstdlib>
#include <sstream>
using namespace llvm;
namespace llvm {
char PIC16FrameOverlay::ID = 0;
ModulePass *createPIC16OverlayPass() { return new PIC16FrameOverlay(); }
}
void PIC16FrameOverlay::getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
AU.addRequired<CallGraph>();
}
void PIC16FrameOverlay::DFSTraverse(CallGraphNode *CGN, unsigned Depth) {
// Do not set any color for external calling node.
if (Depth != 0 && CGN->getFunction()) {
unsigned Color = getColor(CGN->getFunction());
// Handle indirectly called functions
if (Color >= PIC16Overlay::StartIndirectCallColor ||
Depth >= PIC16Overlay::StartIndirectCallColor) {
// All functions called from an indirectly called function are given
// an unique color.
if (Color < PIC16Overlay::StartIndirectCallColor &&
Depth >= PIC16Overlay::StartIndirectCallColor)
setColor(CGN->getFunction(), Depth);
for (unsigned int i = 0; i < CGN->size(); i++)
DFSTraverse((*CGN)[i], ++IndirectCallColor);
return;
}
// Just return if the node already has a color greater than the current
// depth. A node must be colored with the maximum depth that it has.
if (Color >= Depth)
return;
Depth = ModifyDepthForInterrupt(CGN, Depth);
setColor(CGN->getFunction(), Depth);
}
// Color all children of this node with color depth+1.
for (unsigned int i = 0; i < CGN->size(); i++)
DFSTraverse((*CGN)[i], Depth+1);
}
unsigned PIC16FrameOverlay::ModifyDepthForInterrupt(CallGraphNode *CGN,
unsigned Depth) {
Function *Fn = CGN->getFunction();
// Return original Depth if function or section for function do not exist.
if (!Fn || !Fn->hasSection())
return Depth;
// Return original Depth if this function is not marked as interrupt.
if (Fn->getSection().find("interrupt") == string::npos)
return Depth;
Depth = Depth + InterruptDepth;
return Depth;
}
void PIC16FrameOverlay::setColor(Function *Fn, unsigned Color) {
std::string Section = "";
if (Fn->hasSection())
Section = Fn->getSection();
size_t Pos = Section.find(OverlayStr);
// Convert Color to string.
std::stringstream ss;
ss << Color;
std::string ColorString = ss.str();
// If color is already set then reset it with the new value. Else append
// the Color string to section.
if (Pos != std::string::npos) {
Pos += OverlayStr.length();
char c = Section.at(Pos);
unsigned OldColorLength = 0;
while (c >= '0' && c<= '9') {
OldColorLength++;
if (Pos < Section.length() - 1)
Pos++;
else
break;
c = Section.at(Pos);
}
// Replace old color with new one.
Section.replace(Pos-OldColorLength +1, OldColorLength, ColorString);
}
else {
// Append Color information to section string.
if (Fn->hasSection())
Section.append(" ");
Section.append(OverlayStr + ColorString);
}
Fn->setSection(Section);
}
unsigned PIC16FrameOverlay::getColor(Function *Fn) {
int Color = 0;
if (!Fn->hasSection())
return 0;
std::string Section = Fn->getSection();
size_t Pos = Section.find(OverlayStr);
// Return 0 if Color is not set.
if (Pos == std::string::npos)
return 0;
// Set Pos to after "Overlay=".
Pos += OverlayStr.length();
char c = Section.at(Pos);
std::string ColorString = "";
// Find the string representing Color. A Color can only consist of digits.
while (c >= '0' && c<= '9') {
ColorString.append(1,c);
if (Pos < Section.length() - 1)
Pos++;
else
break;
c = Section.at(Pos);
}
Color = atoi(ColorString.c_str());
return Color;
}
bool PIC16FrameOverlay::runOnModule(Module &M) {
CallGraph &CG = getAnalysis<CallGraph>();
CallGraphNode *ECN = CG.getExternalCallingNode();
MarkIndirectlyCalledFunctions(M);
// Since External Calling Node is the base function, do a depth first
// traversal of CallGraph with ECN as root. Each node with be marked with
// a color that is max(color(callers)) + 1.
if(ECN) {
DFSTraverse(ECN, 0);
}
return false;
}
void PIC16FrameOverlay::MarkIndirectlyCalledFunctions(Module &M) {
// If the use of a function is not a call instruction then this
// function might be called indirectly. In that case give it
// an unique color.
for (Module::iterator MI = M.begin(), E = M.end(); MI != E; ++MI) {
for (Value::use_iterator I = MI->use_begin(), E = MI->use_end(); I != E;
++I) {
if ((!isa<CallInst>(I) && !isa<InvokeInst>(I))
|| !CallSite(cast<Instruction>(I)).isCallee(I)) {
setColor(MI, ++IndirectCallColor);
break;
}
}
}
}
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