[PATCH] D133801: Extraction of a matcher for an unused value from an expression from the bugprone-unused-return-value check

[Bartłomiej Cieślar via Phabricator via cfe-commits]

barcisz created this revision.
Herald added a subscriber: carlosgalvezp.
Herald added a project: All.
barcisz requested review of this revision.
Herald added a project: clang-tools-extra.
Herald added a subscriber: cfe-commits.

This diff extracts the matcher for an unused expression result from bugprone-unused-return-value into a utility. This diff is a prerequisite to the diff that introduces 
the cuda-unsafe-api-call-check


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D133801

Files:
  clang-tools-extra/clang-tidy/bugprone/UnusedReturnValueCheck.cpp
  clang-tools-extra/clang-tidy/utils/Matchers.h


Index: clang-tools-extra/clang-tidy/utils/Matchers.h
===================================================================
--- clang-tools-extra/clang-tidy/utils/Matchers.h
+++ clang-tools-extra/clang-tidy/utils/Matchers.h
@@ -49,6 +49,51 @@
   return pointerType(pointee(qualType(isConstQualified())));
 }
 
+// Matches the statements in a GNU statement-expression that are not returned
+// from it.
+AST_MATCHER_P(StmtExpr, hasUnreturning,
+              clang::ast_matchers::internal::Matcher<Stmt>, matcher) {
+  const auto compoundStmt = Node.getSubStmt();
+  assert(compoundStmt);
+
+  clang::ast_matchers::internal::BoundNodesTreeBuilder result;
+  bool matched = false;
+  for (auto stmt = compoundStmt->body_begin();
+       stmt + 1 < compoundStmt->body_end(); ++stmt) {
+    clang::ast_matchers::internal::BoundNodesTreeBuilder builderInner(*Builder);
+    assert(stmt && *stmt);
+    if (matcher.matches(**stmt, Finder, &builderInner)) {
+      result.addMatch(builderInner);
+      matched = true;
+    }
+  }
+  *Builder = result;
+  return matched;
+}
+
+// Matches all of the nodes (simmilar to forEach) that match the matcher
+// and have return values not used in any statement.
+AST_MATCHER_FUNCTION_P(ast_matchers::StatementMatcher, isValueUnused,
+                       ast_matchers::StatementMatcher, Matcher) {
+  using namespace ast_matchers;
+  const auto UnusedInCompoundStmt =
+      compoundStmt(forEach(Matcher), unless(hasParent(stmtExpr())));
+  const auto UnusedInGnuExprStmt = stmtExpr(hasUnreturning(Matcher));
+  const auto UnusedInIfStmt =
+      ifStmt(eachOf(hasThen(Matcher), hasElse(Matcher)));
+  const auto UnusedInWhileStmt = whileStmt(hasBody(Matcher));
+  const auto UnusedInDoStmt = doStmt(hasBody(Matcher));
+  const auto UnusedInForStmt = forStmt(
+      eachOf(hasLoopInit(Matcher), hasIncrement(Matcher), hasBody(Matcher)));
+  const auto UnusedInRangeForStmt = cxxForRangeStmt(hasBody(Matcher));
+  const auto UnusedInCaseStmt = switchCase(forEach(Matcher));
+  const auto Unused =
+      stmt(anyOf(UnusedInCompoundStmt, UnusedInGnuExprStmt, UnusedInIfStmt,
+                 UnusedInWhileStmt, UnusedInDoStmt, UnusedInForStmt,
+                 UnusedInRangeForStmt, UnusedInCaseStmt));
+  return stmt(eachOf(Unused, forEachDescendant(Unused)));
+}
+
 // A matcher implementation that matches a list of type name regular expressions
 // against a NamedDecl. If a regular expression contains the substring "::"
 // matching will occur against the qualified name, otherwise only the typename.
Index: clang-tools-extra/clang-tidy/bugprone/UnusedReturnValueCheck.cpp
===================================================================
--- clang-tools-extra/clang-tidy/bugprone/UnusedReturnValueCheck.cpp
+++ clang-tools-extra/clang-tidy/bugprone/UnusedReturnValueCheck.cpp
@@ -7,6 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "UnusedReturnValueCheck.h"
+#include "../utils/Matchers.h"
 #include "../utils/OptionsUtils.h"
 #include "clang/AST/ASTContext.h"
 #include "clang/ASTMatchers/ASTMatchFinder.h"
@@ -159,10 +160,7 @@
   auto UnusedInCaseStmt = switchCase(forEach(MatchedCallExpr));
 
   Finder->addMatcher(
-      stmt(anyOf(UnusedInCompoundStmt, UnusedInIfStmt, UnusedInWhileStmt,
-                 UnusedInDoStmt, UnusedInForStmt, UnusedInRangeForStmt,
-                 UnusedInCaseStmt)),
-      this);
+      functionDecl(hasBody(matchers::isValueUnused(MatchedCallExpr))), this);
 }
 
 void UnusedReturnValueCheck::check(const MatchFinder::MatchResult &Result) {


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D133801.459842.patch
Type: text/x-patch
Size: 3581 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/cfe-commits/attachments/20220913/060b10d6/attachment.bin>