Revert r350404

This caused https://bugs.llvm.org/show_bug.cgi?id=40642:
"After 350404, clang drops volatile load"

> Refactor the way we handle diagnosing unused expression results.
>
> Rather than sprinkle calls to DiagnoseUnusedExprResult() around in places
> where we want diagnostics, we now diagnose unused expression statements and
> full expressions in a more generic way when acting on the final expression
> statement. This results in more appropriate diagnostics for [[nodiscard]] where
> we were previously lacking them, such as when the body of a for loop is not a
> compound statement.
>
> This patch fixes PR39837.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/branches/release_80@353935 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 9 insertions, 15 deletions

diff --git a/include/clang/Parse/Parser.h b/include/clang/Parse/Parser.h
index 438ff0e2ed..46e4431913 100644
--- a/include/clang/Parse/Parser.h
+++ b/include/clang/Parse/Parser.h
@@ -360,11 +360,6 @@ class Parser : public CodeCompletionHandler {
   /// just a regular sub-expression.
   SourceLocation ExprStatementTokLoc;
 
-  /// Tests whether an expression value is discarded based on token lookahead.
-  /// It will return true if the lexer is currently processing the })
-  /// terminating a GNU statement expression and false otherwise.
-  bool isExprValueDiscarded();
-
 public:
   Parser(Preprocessor &PP, Sema &Actions, bool SkipFunctionBodies);
   ~Parser() override;
diff --git a/include/clang/Sema/Sema.h b/include/clang/Sema/Sema.h
index e5b7465820..ced5773f0c 100644
--- a/include/clang/Sema/Sema.h
+++ b/include/clang/Sema/Sema.h
@@ -1369,7 +1369,6 @@ public:
   void PopCompoundScope();
 
   sema::CompoundScopeInfo &getCurCompoundScope() const;
-  bool isCurCompoundStmtAStmtExpr() const;
 
   bool hasAnyUnrecoverableErrorsInThisFunction() const;
 
@@ -3690,17 +3689,16 @@ public:
     return MakeFullExpr(Arg, Arg ? Arg->getExprLoc() : SourceLocation());
   }
   FullExprArg MakeFullExpr(Expr *Arg, SourceLocation CC) {
-    return FullExprArg(
-        ActOnFinishFullExpr(Arg, CC, /*DiscardedValue*/ false).get());
+    return FullExprArg(ActOnFinishFullExpr(Arg, CC).get());
   }
   FullExprArg MakeFullDiscardedValueExpr(Expr *Arg) {
     ExprResult FE =
-        ActOnFinishFullExpr(Arg, Arg ? Arg->getExprLoc() : SourceLocation(),
-                            /*DiscardedValue*/ true);
+      ActOnFinishFullExpr(Arg, Arg ? Arg->getExprLoc() : SourceLocation(),
+                          /*DiscardedValue*/ true);
     return FullExprArg(FE.get());
   }
 
-  StmtResult ActOnExprStmt(ExprResult Arg, bool DiscardedValue = true);
+  StmtResult ActOnExprStmt(ExprResult Arg);
   StmtResult ActOnExprStmtError();
 
   StmtResult ActOnNullStmt(SourceLocation SemiLoc,
@@ -5346,12 +5344,13 @@ public:
   CreateMaterializeTemporaryExpr(QualType T, Expr *Temporary,
                                  bool BoundToLvalueReference);
 
-  ExprResult ActOnFinishFullExpr(Expr *Expr, bool DiscardedValue) {
-    return ActOnFinishFullExpr(
-        Expr, Expr ? Expr->getExprLoc() : SourceLocation(), DiscardedValue);
+  ExprResult ActOnFinishFullExpr(Expr *Expr) {
+    return ActOnFinishFullExpr(Expr, Expr ? Expr->getExprLoc()
+                                          : SourceLocation());
   }
   ExprResult ActOnFinishFullExpr(Expr *Expr, SourceLocation CC,
-                                 bool DiscardedValue, bool IsConstexpr = false);
+                                 bool DiscardedValue = false,
+                                 bool IsConstexpr = false);
   StmtResult ActOnFinishFullStmt(Stmt *Stmt);
 
   // Marks SS invalid if it represents an incomplete type.