From b058dd52590462f564238275527e7f061ff9e08a Mon Sep 17 00:00:00 2001 From: Wentao Zhang <35722712+whentojump@users.noreply.github.com> Date: Thu, 22 Feb 2024 16:04:25 -0600 Subject: [PATCH] [clang][CodeGen] Keep processing the rest of AST after encountering unsupported MC/DC expressions (#82464) Currently, upon seeing unsupported decisions (more than 6 conditions, or split nesting), the post-visitor hook dataTraverseStmtPost() returns a false. As a result, in the rest of tree even supported decisions will be skipped as well. Like in the below code: { // CompoundStmt a && b; // 1: BinaryOperator (supported) a && foo(b && c); // 2: BinaryOperator (not yet supported due to split // nesting) a && b; // 3: BinaryOperator (supported) } Decision 3 will not be processed at all. And only one "Decision" region will be emitted. Compiler explorer example: https://godbolt.org/z/Px61sesoo We hope to process such cases and emit two "Decision" regions (1 and 3) in the above example. (cherry picked from commit d4bfca3b2e673789f7c278d46a199ae8910ddd37) --- clang/lib/CodeGen/CodeGenPGO.cpp | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/clang/lib/CodeGen/CodeGenPGO.cpp b/clang/lib/CodeGen/CodeGenPGO.cpp index 5d7c3847745762..fb4e86e8bd8053 100644 --- a/clang/lib/CodeGen/CodeGenPGO.cpp +++ b/clang/lib/CodeGen/CodeGenPGO.cpp @@ -240,9 +240,12 @@ struct MapRegionCounters : public RecursiveASTVisitor { if (MCDCMaxCond == 0) return true; - /// At the top of the logical operator nest, reset the number of conditions. - if (LogOpStack.empty()) + /// At the top of the logical operator nest, reset the number of conditions, + /// also forget previously seen split nesting cases. + if (LogOpStack.empty()) { NumCond = 0; + SplitNestedLogicalOp = false; + } if (const Expr *E = dyn_cast(S)) { const BinaryOperator *BinOp = dyn_cast(E->IgnoreParens()); @@ -293,7 +296,7 @@ struct MapRegionCounters : public RecursiveASTVisitor { "contains an operation with a nested boolean expression. " "Expression will not be covered"); Diag.Report(S->getBeginLoc(), DiagID); - return false; + return true; } /// Was the maximum number of conditions encountered? @@ -304,7 +307,7 @@ struct MapRegionCounters : public RecursiveASTVisitor { "number of conditions (%0) exceeds max (%1). " "Expression will not be covered"); Diag.Report(S->getBeginLoc(), DiagID) << NumCond << MCDCMaxCond; - return false; + return true; } // Otherwise, allocate the number of bytes required for the bitmap