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using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Diagnostics;
using Microsoft.Boogie;
namespace GPUVerify
{
class LiveVariableAnalyser
{
private GPUVerifier verifier;
// Maps procedure -> loop -> set of variables live at the loop head
private Dictionary<string, Dictionary<string, HashSet<string>>> liveVariableInfo;
public LiveVariableAnalyser(GPUVerifier verifier)
{
this.verifier = verifier;
this.liveVariableInfo = new Dictionary<string, Dictionary<string, HashSet<string>>>();
}
internal void Analyse()
{
foreach (Declaration D in verifier.Program.TopLevelDeclarations)
{
if (D is Implementation)
{
Implementation impl = D as Implementation;
liveVariableInfo[impl.Name] = new Dictionary<string, HashSet<string>>();
LiveVariableAnalysis.ComputeLiveVariables(impl);
Analyse(impl.StructuredStmts, impl);
}
}
}
private void Analyse(StmtList stmtList, Implementation impl)
{
foreach (BigBlock bb in stmtList.BigBlocks)
{
Analyse(bb, impl);
}
}
private void Analyse(BigBlock bb, Implementation impl)
{
if (bb.ec is WhileCmd)
{
WhileCmd wc = bb.ec as WhileCmd;
Debug.Assert(wc.Invariants.Count >= 1);
string wcLabel = wc.Invariants[0].Attributes.Key;
Debug.Assert (wcLabel.Contains("loophead_"));
liveVariableInfo[impl.Name][wcLabel] = new HashSet<string>();
Block wcStartBlock = GetBlockForWhile(wc, impl);
Debug.Assert(wcStartBlock != null);
// Debug.Assert(wcStartBlock.liveVarsBefore != null);
if (wcStartBlock.liveVarsBefore == null)
{
}
else
{
foreach (Variable v in impl.LocVars)
{
if (wcStartBlock.IsLive(v))
{
liveVariableInfo[impl.Name][wcLabel].Add(v.Name);
}
}
}
Analyse(wc.Body, impl);
}
else if (bb.ec is IfCmd)
{
Analyse((bb.ec as IfCmd).thn, impl);
if ((bb.ec as IfCmd).elseBlock != null)
{
Analyse((bb.ec as IfCmd).elseBlock, impl);
}
Debug.Assert((bb.ec as IfCmd).elseIf == null);
}
}
private Block GetBlockForWhile(WhileCmd wc, Implementation impl)
{
string whileLoopIdentifier =
wc.Invariants[0].Attributes.Key;
foreach (Block b in impl.Blocks)
{
if (b.Cmds.Length > 0 && b.Cmds[0] is AssertCmd)
{
AssertCmd ass = b.Cmds[0] as AssertCmd;
if (ass.Attributes != null)
{
if (ass.Attributes.Key.Equals(whileLoopIdentifier))
{
return b;
}
}
}
}
Debug.Assert(false);
return null;
}
}
}
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