/// <summary>
/// Extracts structured program constructs out of snarled goto nests, if possible.
/// Since procedures are now independent of each other, this analysis
/// is done one procedure at a time.
/// </summary>
public void StructureProgram()
{
foreach (var program in project.Programs)
{
int i = 0;
foreach (Procedure proc in program.Procedures.Values)
{
try
{
eventListener.ShowProgress("Rewriting procedures to high-level language.", i, program.Procedures.Values.Count);
++i;
Console.WriteLine("rewriting: {0}", proc);
IStructureAnalysis sa = new StructureAnalysis(proc);
sa.Structure();
}
catch (Exception e)
{
eventListener.Error(
eventListener.CreateProcedureNavigator(program, proc),
e,
"An error occurred while rewriting procedure to high-level language.");
}
}
WriteDecompilerProducts();
}
eventListener.ShowStatus("Rewriting complete.");
}
/// <summary>
/// Extracts structured program constructs out of snarled goto nests, if possible.
/// Since procedures are now independent of each other, this analysis
/// is done one procedure at a time.
/// </summary>
public void StructureProgram()
{
if (project is null)
{
return;
}
foreach (var program in project.Programs)
{
int i = 0;
foreach (Procedure proc in program.Procedures.Values)
{
if (eventListener.IsCanceled())
{
return;
}
try
{
eventListener.ShowProgress("Rewriting procedures to high-level language.", i, program.Procedures.Values.Count);
++i;
IStructureAnalysis sa = new StructureAnalysis(eventListener, program, proc);
sa.Structure();
}
catch (Exception e)
{
eventListener.Error(
eventListener.CreateProcedureNavigator(program, proc),
e,
"An error occurred while rewriting procedure to high-level language.");
}
}
}
project.FireScriptEvent(ScriptEvent.OnProgramDecompiled);
WriteDecompilerProducts();
eventListener.ShowStatus("Rewriting complete.");
}
/// <summary>
/// Processes procedures individually, building complex expression
/// trees out of the simple, close-to-the-machine code generated by
/// the disassembly.
/// </summary>
/// <param name="rl"></param>
public void BuildExpressionTrees()
{
eventListener.ShowProgress("Building expressions.", 0, program.Procedures.Count);
foreach (var sst in this.ssts)
{
var ssa = sst.SsaState;
try
{
DumpWatchedProcedure("Before expression coalescing", ssa.Procedure);
// Procedures should be untangled from each other. Now process
// each one separately.
DeadCode.Eliminate(ssa);
// Build expressions. A definition with a single use can be subsumed
// into the using expression.
var coa = new Coalescer(ssa);
coa.Transform();
DeadCode.Eliminate(ssa);
var vp = new ValuePropagator(program.SegmentMap, ssa, program.CallGraph, dynamicLinker, eventListener);
vp.Transform();
DumpWatchedProcedure("After expression coalescing", ssa.Procedure);
var liv = new LinearInductionVariableFinder(
ssa,
new BlockDominatorGraph(
ssa.Procedure.ControlGraph,
ssa.Procedure.EntryBlock));
liv.Find();
foreach (var de in liv.Contexts)
{
var str = new StrengthReduction(ssa, de.Key, de.Value);
str.ClassifyUses();
str.ModifyUses();
}
DeadCode.Eliminate(ssa);
DumpWatchedProcedure("After strength reduction", ssa.Procedure);
// Definitions with multiple uses and variables joined by PHI functions become webs.
var web = new WebBuilder(program, ssa, program.InductionVariables, eventListener);
web.Transform();
ssa.ConvertBack(false);
DumpWatchedProcedure("After data flow analysis", ssa.Procedure);
}
catch (Exception ex)
{
eventListener.Error(
eventListener.CreateProcedureNavigator(program, ssa.Procedure),
ex,
"An internal error occurred while building the expressions of {0}",
ssa.Procedure.Name);
}
eventListener.Advance(1);
}
}
/// <summary>
/// Executes the core of the analysis
/// </summary>
/// <remarks>
/// The algorithm visits nodes in post-order in each iteration. This
/// means that all descendants of a node will be visited (and
/// hence had the chance to be reduced) before the node itself.
/// The algorithm’s behavior when visiting node _n_
/// depends on hether the region at _n_
/// is acyclic (has no loop) or not. For an acyclic region, the
/// algorithm tries to match the subgraph
/// at _n_to an acyclic schemas (3.2). If there is no match,
/// and the region is a switch candidate, then it attempts to
/// refine the region at _n_ into a switch region.
///
/// If _n_ is cyclic, the algorithm
/// compares the region at _n_ to the cyclic schemata.
/// If this fails, it refines _n_ into a loop (3.6).
///
/// If both matching and refinement do not make progress, the
/// current node _n_ is then skipped for the current iteration of
/// the algorithm. If there is an iteration in which all
/// nodes are skipped, i.e., the algorithm makes no progress, then
/// the algorithm employs a last resort refinement (3.7) to
/// ensure that progress can be made in the next iteration.
/// </remarks>
public Region Execute()
{
var result = BuildRegionGraph(proc);
this.regionGraph = result.Item1;
this.entry = result.Item2;
int iterations = 0;
int oldCount;
int newCount;
do
{
if (eventListener.IsCanceled())
break;
++iterations;
if (iterations > 1000)
{
eventListener.Warn(
eventListener.CreateProcedureNavigator(program, proc),
"Structure analysis stopped making progress, quitting. Please report this issue at https://github.com/uxmal/reko");
DumpGraph();
break;
}
oldCount = regionGraph.Nodes.Count;
this.doms = new DominatorGraph<Region>(this.regionGraph, result.Item2);
this.unresolvedCycles = new Queue<Tuple<Region, ISet<Region>>>();
this.unresolvedNoncycles = new Queue<Tuple<Region, ISet<Region>>>();
var postOrder = new DfsIterator<Region>(regionGraph).PostOrder(entry).ToList();
bool didReduce = false;
foreach (var n in postOrder)
{
Probe();
didReduce = false;
do
{
if (eventListener.IsCanceled())
break;
didReduce = ReduceAcyclic(n);
if (!didReduce && IsCyclic(n))
{
didReduce = ReduceCyclic(n);
}
} while (didReduce);
}
newCount = regionGraph.Nodes.Count;
if (newCount == oldCount && newCount > 1)
{
// Didn't make any progress this round,
// try refining unstructured regions
ProcessUnresolvedRegions();
}
} while (regionGraph.Nodes.Count > 1);
return entry;
}
/// <summary>
/// Processes procedures individually, building complex expression
/// trees out of the simple, close-to-the-machine code generated by
/// the disassembly.
/// </summary>
/// <param name="rl"></param>
public void BuildExpressionTrees()
{
eventListener.ShowProgress("Building expressions.", 0, program.Procedures.Count);
foreach (var sst in this.ssts !)
{
var ssa = sst.SsaState;
try
{
if (program.User.AggressiveBranchRemoval)
{
// This ends up being very aggressive and doesn't replicate the original
// binary code. See discussion on https://github.com/uxmal/reko/issues/932
DumpWatchedProcedure("urb", "Before unreachable block removal", ssa.Procedure);
var urb = new UnreachableBlockRemover(ssa, eventListener);
urb.Transform();
}
DumpWatchedProcedure("precoa", "Before expression coalescing", ssa.Procedure);
// Procedures should be untangled from each other. Now process
// each one separately.
DeadCode.Eliminate(ssa);
// Build expressions. A definition with a single use can be subsumed
// into the using expression.
var coa = new Coalescer(ssa);
coa.Transform();
DeadCode.Eliminate(ssa);
var vp = new ValuePropagator(program.SegmentMap, ssa, program.CallGraph, dynamicLinker, eventListener);
vp.Transform();
DumpWatchedProcedure("postcoa", "After expression coalescing", ssa.Procedure);
var liv = new LinearInductionVariableFinder(
ssa,
new BlockDominatorGraph(
ssa.Procedure.ControlGraph,
ssa.Procedure.EntryBlock));
liv.Find();
foreach (var de in liv.Contexts)
{
var str = new StrengthReduction(ssa, de.Key, de.Value);
str.ClassifyUses();
str.ModifyUses();
}
DeadCode.Eliminate(ssa);
DumpWatchedProcedure("sr", "After strength reduction", ssa.Procedure);
// Definitions with multiple uses and variables joined by PHI functions become webs.
var web = new WebBuilder(program, ssa, program.InductionVariables, eventListener);
web.Transform();
ssa.ConvertBack(false);
DumpWatchedProcedure("dfa", "After data flow analysis", ssa.Procedure);
}
catch (Exception ex)
{
eventListener.Error(
eventListener.CreateProcedureNavigator(program, ssa.Procedure),
ex,
"An internal error occurred while building the expressions of {0}",
ssa.Procedure.Name);
}
eventListener.Advance(1);
}
}