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[clang][dataflow] In the CFG visualization, mark converged blocks. (#…
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…79999)

Here's an example of the output:


![image](https://github.com/llvm/llvm-project/assets/29098113/63cd509e-c2a7-4794-b758-ea73812ff09f)
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@martinboehme
martinboehme committed Jan 31, 2024
1 parent ee01a2c commit 82324bc
Showing 1 changed file with 60 additions and 42 deletions.
102 changes: 60 additions & 42 deletions clang/lib/Analysis/FlowSensitive/HTMLLogger.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -158,13 +158,17 @@ class HTMLLogger : public Logger {

StreamFactory Streams;
std::unique_ptr<llvm::raw_ostream> OS;
std::optional<llvm::json::OStream> JOS;
std::string JSON;
llvm::raw_string_ostream JStringStream{JSON};
llvm::json::OStream JOS{JStringStream, /*Indent=*/2};

const ControlFlowContext *CFG;
// Timeline of iterations of CFG block visitation.
std::vector<Iteration> Iters;
// Indexes in `Iters` of the iterations for each block.
llvm::DenseMap<const CFGBlock *, llvm::SmallVector<size_t>> BlockIters;
// For a given block ID, did the block converge (on the last iteration)?
llvm::BitVector BlockConverged;
// The messages logged in the current context but not yet written.
std::string ContextLogs;
// The number of elements we have visited within the current CFG block.
Expand All @@ -178,6 +182,8 @@ class HTMLLogger : public Logger {
this->CFG = &CFG;
*OS << llvm::StringRef(HTMLLogger_html).split("<?INJECT?>").first;

BlockConverged.resize(CFG.getCFG().getNumBlockIDs());

const auto &D = CFG.getDecl();
const auto &SM = A.getASTContext().getSourceManager();
*OS << "<title>";
Expand All @@ -191,37 +197,37 @@ class HTMLLogger : public Logger {
*OS << "<script>" << HTMLLogger_js << "</script>\n";

writeCode();
writeCFG();

*OS << "<script>var HTMLLoggerData = \n";
JOS.emplace(*OS, /*Indent=*/2);
JOS->objectBegin();
JOS->attributeBegin("states");
JOS->objectBegin();
JOS.objectBegin();
JOS.attributeBegin("states");
JOS.objectBegin();
}
// Between beginAnalysis() and endAnalysis() we write all the states for
// particular analysis points into the `timeline` array.
void endAnalysis() override {
JOS->objectEnd();
JOS->attributeEnd();
JOS.objectEnd();
JOS.attributeEnd();

JOS->attributeArray("timeline", [&] {
JOS.attributeArray("timeline", [&] {
for (const auto &E : Iters) {
JOS->object([&] {
JOS->attribute("block", blockID(E.Block->getBlockID()));
JOS->attribute("iter", E.Iter);
JOS->attribute("post_visit", E.PostVisit);
JOS->attribute("converged", E.Converged);
JOS.object([&] {
JOS.attribute("block", blockID(E.Block->getBlockID()));
JOS.attribute("iter", E.Iter);
JOS.attribute("post_visit", E.PostVisit);
JOS.attribute("converged", E.Converged);
});
}
});
JOS->attributeObject("cfg", [&] {
JOS.attributeObject("cfg", [&] {
for (const auto &E : BlockIters)
writeBlock(*E.first, E.second);
});

JOS->objectEnd();
JOS.reset();
JOS.objectEnd();

writeCFG();

*OS << "<script>var HTMLLoggerData = \n";
*OS << JSON;
*OS << ";\n</script>\n";
*OS << llvm::StringRef(HTMLLogger_html).split("<?INJECT?>").second;
}
Expand All @@ -231,6 +237,8 @@ class HTMLLogger : public Logger {
unsigned IterNum = BIter.size() + 1;
BIter.push_back(Iters.size());
Iters.push_back({&B, IterNum, PostVisit, /*Converged=*/false});
if (!PostVisit)
BlockConverged[B.getBlockID()] = false;
ElementIndex = 0;
}
void enterElement(const CFGElement &E) override {
Expand Down Expand Up @@ -261,11 +269,11 @@ class HTMLLogger : public Logger {
unsigned Block = Iters.back().Block->getBlockID();
unsigned Iter = Iters.back().Iter;
bool PostVisit = Iters.back().PostVisit;
JOS->attributeObject(elementIterID(Block, Iter, ElementIndex), [&] {
JOS->attribute("block", blockID(Block));
JOS->attribute("iter", Iter);
JOS->attribute("post_visit", PostVisit);
JOS->attribute("element", ElementIndex);
JOS.attributeObject(elementIterID(Block, Iter, ElementIndex), [&] {
JOS.attribute("block", blockID(Block));
JOS.attribute("iter", Iter);
JOS.attribute("post_visit", PostVisit);
JOS.attribute("element", ElementIndex);

// If this state immediately follows an Expr, show its built-in model.
if (ElementIndex > 0) {
Expand All @@ -274,28 +282,31 @@ class HTMLLogger : public Logger {
if (const Expr *E = S ? llvm::dyn_cast<Expr>(S->getStmt()) : nullptr) {
if (E->isPRValue()) {
if (auto *V = State.Env.getValue(*E))
JOS->attributeObject(
"value", [&] { ModelDumper(*JOS, State.Env).dump(*V); });
JOS.attributeObject(
"value", [&] { ModelDumper(JOS, State.Env).dump(*V); });
} else {
if (auto *Loc = State.Env.getStorageLocation(*E))
JOS->attributeObject(
"value", [&] { ModelDumper(*JOS, State.Env).dump(*Loc); });
JOS.attributeObject(
"value", [&] { ModelDumper(JOS, State.Env).dump(*Loc); });
}
}
}
if (!ContextLogs.empty()) {
JOS->attribute("logs", ContextLogs);
JOS.attribute("logs", ContextLogs);
ContextLogs.clear();
}
{
std::string BuiltinLattice;
llvm::raw_string_ostream BuiltinLatticeS(BuiltinLattice);
State.Env.dump(BuiltinLatticeS);
JOS->attribute("builtinLattice", BuiltinLattice);
JOS.attribute("builtinLattice", BuiltinLattice);
}
});
}
void blockConverged() override { Iters.back().Converged = true; }
void blockConverged() override {
Iters.back().Converged = true;
BlockConverged[Iters.back().Block->getBlockID()] = true;
}

void logText(llvm::StringRef S) override {
ContextLogs.append(S.begin(), S.end());
Expand All @@ -307,23 +318,23 @@ class HTMLLogger : public Logger {
// Currently this is just the list of elements in execution order.
// FIXME: an AST dump would be a useful view, too.
void writeBlock(const CFGBlock &B, llvm::ArrayRef<size_t> ItersForB) {
JOS->attributeObject(blockID(B.getBlockID()), [&] {
JOS->attributeArray("iters", [&] {
JOS.attributeObject(blockID(B.getBlockID()), [&] {
JOS.attributeArray("iters", [&] {
for (size_t IterIdx : ItersForB) {
const Iteration &Iter = Iters[IterIdx];
JOS->object([&] {
JOS->attribute("iter", Iter.Iter);
JOS->attribute("post_visit", Iter.PostVisit);
JOS->attribute("converged", Iter.Converged);
JOS.object([&] {
JOS.attribute("iter", Iter.Iter);
JOS.attribute("post_visit", Iter.PostVisit);
JOS.attribute("converged", Iter.Converged);
});
}
});
JOS->attributeArray("elements", [&] {
JOS.attributeArray("elements", [&] {
for (const auto &Elt : B.Elements) {
std::string Dump;
llvm::raw_string_ostream DumpS(Dump);
Elt.dumpToStream(DumpS);
JOS->value(Dump);
JOS.value(Dump);
}
});
});
Expand Down Expand Up @@ -477,7 +488,7 @@ class HTMLLogger : public Logger {
}

// Produce a graphviz description of a CFG.
static std::string buildCFGDot(const clang::CFG &CFG) {
std::string buildCFGDot(const clang::CFG &CFG) {
std::string Graph;
llvm::raw_string_ostream GraphS(Graph);
// Graphviz likes to add unhelpful tooltips everywhere, " " suppresses.
Expand All @@ -486,8 +497,15 @@ class HTMLLogger : public Logger {
node[class=bb, shape=square, fontname="sans-serif", tooltip=" "]
edge[tooltip = " "]
)";
for (unsigned I = 0; I < CFG.getNumBlockIDs(); ++I)
GraphS << " " << blockID(I) << " [id=" << blockID(I) << "]\n";
for (unsigned I = 0; I < CFG.getNumBlockIDs(); ++I) {
std::string Name = blockID(I);
// Rightwards arrow, vertical line
char ConvergenceMarker[] = u8"\\n\u2192\u007c";
if (BlockConverged[I])
Name += ConvergenceMarker;
GraphS << " " << blockID(I) << " [id=" << blockID(I) << " label=\""
<< Name << "\"]\n";
}
for (const auto *Block : CFG) {
for (const auto &Succ : Block->succs()) {
if (Succ.getReachableBlock())
Expand Down

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