Add a warning to diagnose statements in C++ like "*(volatile int*)x;". Conceptually, this is part of -Wunused-value, but I added a separate flag -Wunused-volatile-lvalue so it doesn't get turned off by accident with -Wno-unused-value. I also made a few minor improvements to existing unused value warnings in the process. <rdar://problem/11516811>.
llvm-svn: 157362
diff --git a/clang/lib/Sema/SemaStmt.cpp b/clang/lib/Sema/SemaStmt.cpp
index f64fc96..a342cbd 100644
--- a/clang/lib/Sema/SemaStmt.cpp
+++ b/clang/lib/Sema/SemaStmt.cpp
@@ -153,10 +153,11 @@
if (!E)
return;
+ const Expr *WarnExpr;
SourceLocation Loc;
SourceRange R1, R2;
if (SourceMgr.isInSystemMacro(E->getExprLoc()) ||
- !E->isUnusedResultAWarning(Loc, R1, R2, Context))
+ !E->isUnusedResultAWarning(WarnExpr, Loc, R1, R2, Context))
return;
// Okay, we have an unused result. Depending on what the base expression is,
@@ -171,7 +172,7 @@
if (DiagnoseUnusedComparison(*this, E))
return;
- E = E->IgnoreParenImpCasts();
+ E = WarnExpr;
if (const CallExpr *CE = dyn_cast<CallExpr>(E)) {
if (E->getType()->isVoidType())
return;
@@ -229,6 +230,11 @@
}
}
+ if (E->isGLValue() && E->getType().isVolatileQualified()) {
+ Diag(Loc, diag::warn_unused_volatile) << R1 << R2;
+ return;
+ }
+
DiagRuntimeBehavior(Loc, 0, PDiag(DiagID) << R1 << R2);
}