[FIRRTL] InferWidths: fix invalid frame reference

The frame.indent reference can be invalidated when we push to the worklist. This change caches the indentation level locally to fix the issue.
llvm · Oct 13, 2024 · 3e3345e · 3e3345e
1 parent 9dea002
commit 3e3345e
Showing 1 changed file with 16 additions and 18 deletions.
diff --git a/lib/Dialect/FIRRTL/Transforms/InferWidths.cpp b/lib/Dialect/FIRRTL/Transforms/InferWidths.cpp
@@ -887,6 +887,7 @@ static ExprSolution solveExpr(Expr *expr, SmallPtrSetImpl<Expr *> &seenVars,
 
   while (!worklist.empty()) {
     auto &frame = worklist.back();
+    auto indent = frame.indent;
     auto setSolution = [&](ExprSolution solution) {
       // Memoize the result.
       if (solution.first && !solution.second)
@@ -897,11 +898,10 @@ static ExprSolution solveExpr(Expr *expr, SmallPtrSetImpl<Expr *> &seenVars,
       LLVM_DEBUG({
         if (!isa<KnownExpr>(frame.expr)) {
           if (solution.first)
-            llvm::dbgs().indent(frame.indent * 2)
+            llvm::dbgs().indent(indent * 2)
                 << "= Solved " << *frame.expr << " = " << *solution.first;
           else
-            llvm::dbgs().indent(frame.indent * 2)
-                << "= Skipped " << *frame.expr;
+            llvm::dbgs().indent(indent * 2) << "= Skipped " << *frame.expr;
           llvm::dbgs() << " (" << (solution.second ? "cycle broken" : "unique")
                        << ")\n";
         }
@@ -914,9 +914,8 @@ static ExprSolution solveExpr(Expr *expr, SmallPtrSetImpl<Expr *> &seenVars,
     if (frame.expr->getSolution()) {
       LLVM_DEBUG({
         if (!isa<KnownExpr>(frame.expr))
-          llvm::dbgs().indent(frame.indent * 2)
-              << "- Cached " << *frame.expr << " = "
-              << *frame.expr->getSolution() << "\n";
+          llvm::dbgs().indent(indent * 2) << "- Cached " << *frame.expr << " = "
+                                          << *frame.expr->getSolution() << "\n";
       });
       setSolution(ExprSolution{*frame.expr->getSolution(), false});
       continue;
@@ -925,8 +924,7 @@ static ExprSolution solveExpr(Expr *expr, SmallPtrSetImpl<Expr *> &seenVars,
     // Otherwise compute the value of the expression.
     LLVM_DEBUG({
       if (!isa<KnownExpr>(frame.expr))
-        llvm::dbgs().indent(frame.indent * 2)
-            << "- Solving " << *frame.expr << "\n";
+        llvm::dbgs().indent(indent * 2) << "- Solving " << *frame.expr << "\n";
     });
 
     TypeSwitch<Expr *>(frame.expr)
@@ -960,21 +958,21 @@ static ExprSolution solveExpr(Expr *expr, SmallPtrSetImpl<Expr *> &seenVars,
           if (!seenVars.insert(expr).second)
             return setSolution(ExprSolution{std::nullopt, true});
 
-          worklist.emplace_back(expr->constraint, frame.indent + 1);
+          worklist.emplace_back(expr->constraint, indent + 1);
           if (expr->upperBound)
-            worklist.emplace_back(expr->upperBound, frame.indent + 1);
+            worklist.emplace_back(expr->upperBound, indent + 1);
         })
         .Case<IdExpr>([&](auto *expr) {
           if (solvedExprs.contains(expr->arg))
             return setSolution(solvedExprs[expr->arg]);
-          worklist.emplace_back(expr->arg, frame.indent + 1);
+          worklist.emplace_back(expr->arg, indent + 1);
         })
         .Case<PowExpr>([&](auto *expr) {
           if (solvedExprs.contains(expr->arg))
             return setSolution(computeUnary(
                 solvedExprs[expr->arg], [](int32_t arg) { return 1 << arg; }));
 
-          worklist.emplace_back(expr->arg, frame.indent + 1);
+          worklist.emplace_back(expr->arg, indent + 1);
         })
         .Case<AddExpr>([&](auto *expr) {
           if (solvedExprs.contains(expr->lhs()) &&
@@ -983,8 +981,8 @@ static ExprSolution solveExpr(Expr *expr, SmallPtrSetImpl<Expr *> &seenVars,
                 solvedExprs[expr->lhs()], solvedExprs[expr->rhs()],
                 [](int32_t lhs, int32_t rhs) { return lhs + rhs; }));
 
-          worklist.emplace_back(expr->lhs(), frame.indent + 1);
-          worklist.emplace_back(expr->rhs(), frame.indent + 1);
+          worklist.emplace_back(expr->lhs(), indent + 1);
+          worklist.emplace_back(expr->rhs(), indent + 1);
         })
         .Case<MaxExpr>([&](auto *expr) {
           if (solvedExprs.contains(expr->lhs()) &&
@@ -993,8 +991,8 @@ static ExprSolution solveExpr(Expr *expr, SmallPtrSetImpl<Expr *> &seenVars,
                 solvedExprs[expr->lhs()], solvedExprs[expr->rhs()],
                 [](int32_t lhs, int32_t rhs) { return std::max(lhs, rhs); }));
 
-          worklist.emplace_back(expr->lhs(), frame.indent + 1);
-          worklist.emplace_back(expr->rhs(), frame.indent + 1);
+          worklist.emplace_back(expr->lhs(), indent + 1);
+          worklist.emplace_back(expr->rhs(), indent + 1);
         })
         .Case<MinExpr>([&](auto *expr) {
           if (solvedExprs.contains(expr->lhs()) &&
@@ -1003,8 +1001,8 @@ static ExprSolution solveExpr(Expr *expr, SmallPtrSetImpl<Expr *> &seenVars,
                 solvedExprs[expr->lhs()], solvedExprs[expr->rhs()],
                 [](int32_t lhs, int32_t rhs) { return std::min(lhs, rhs); }));
 
-          worklist.emplace_back(expr->lhs(), frame.indent + 1);
-          worklist.emplace_back(expr->rhs(), frame.indent + 1);
+          worklist.emplace_back(expr->lhs(), indent + 1);
+          worklist.emplace_back(expr->rhs(), indent + 1);
         })
         .Default([&](auto) {
           setSolution(ExprSolution{std::nullopt, false});