Higuoxing updated this revision to Diff 151290.
Higuoxing added a comment.
Ping, well, I think I understand `@dexonsmith`'s idea.
`Actionable` macro argument is just like something like this
#define foo(x) ( (void)(x) )
when we using it by
foo(a && b || c);
we could add parentheses for it by
foo((a && b) || c);
However, the following example is `not actionable`
#define foo(op0, op1, x, y, z) ( (void)(x op0 y op1 z) )
when we using it by
foo(&&, ||, x, y, z);
because, we also probably use it by
foo(+, *, x, y, z)
So, we cannot add parentheses for it carelessly...
My opinion is that, to judge if an `expr` is actionable is to test if the op
and both LHS and RHS are from same context or same argument position from
macro... But I cannot find such API for indicating a `expression` expanded
position exactly. There are API like: `isMacroArgExpansion` and
`isMacroBodyExpansion` which is determined by row string positions...
So, what I can do now for this is that using API `isMacroArgExpansion()` to let
it check the parentheses defined or expanded totally inside a macro like
#define foo(x, y, z) ( x && y || z )
The shortage is that we cannot check parentheses for this case:
foo(x && y || z);
because the operator is expanded from macro arguments.
Thanks
https://reviews.llvm.org/D47687
Files:
lib/Sema/SemaExpr.cpp
test/Sema/logical-op-parentheses-in-macros.c
Index: test/Sema/logical-op-parentheses-in-macros.c
===================================================================
--- test/Sema/logical-op-parentheses-in-macros.c
+++ test/Sema/logical-op-parentheses-in-macros.c
@@ -0,0 +1,49 @@
+// RUN: %clang_cc1 -Wparentheses -fsyntax-only -verify=logical_op_parentheses_check %s
+
+// operator of this case is expanded from macro function argument
+#define macro_op_parentheses_check(x) ( \
+ ( (void)(x) ) \
+)
+
+// operator of this case is expanded from macro function body
+#define macro_op_parentheses_check_ops_args(op0, op1, x, y, z) ( \
+ ( (void) (x op0 y op1 z ) ) \
+)
+
+// operator of this case is expanded from macro function body
+#define macro_op_parentheses_check_ops_args2(op0, op1, op2, w, x, y, z) ( \
+ ( (void) (w op0 x op1 y op2 z) ) \
+)
+
+// operator of this case is expanded from marco body
+#define macro_op_parentheses_check_ops_body(x, y, z) ( \
+ ( (void) (x && y || z) ) \
+)
+
+void logical_op_from_macro_arguments(unsigned i) {
+ macro_op_parentheses_check(i || i && i); // no warning.
+ macro_op_parentheses_check(i || i && "I love LLVM"); // no warning.
+ macro_op_parentheses_check("I love LLVM" && i || i); // no warning.
+
+ macro_op_parentheses_check(i || i && "I love LLVM" || i); // no warning.
+ macro_op_parentheses_check(i || "I love LLVM" && i || i); // no warning.
+ macro_op_parentheses_check(i && i || 0); // no warning.
+ macro_op_parentheses_check(0 || i && i); // no warning.
+}
+
+void logical_op_from_macro_arguments2(unsigned i) {
+ macro_op_parentheses_check_ops_args(||, &&, i, i, i); // no warning.
+ macro_op_parentheses_check_ops_args(||, &&, i, i, "I love LLVM"); // no warning.
+ macro_op_parentheses_check_ops_args(&&, ||, "I love LLVM", i, i); // no warning.
+
+ macro_op_parentheses_check_ops_args2(||, &&, ||, i, i, "I love LLVM", i); // no warning.
+ macro_op_parentheses_check_ops_args2(||, &&, ||, i, "I love LLVM", i, i); // no warning.
+
+ macro_op_parentheses_check_ops_args(&&, ||, i, i, 0); // no warning.
+ macro_op_parentheses_check_ops_args(||, &&, 0, i, i); // no warning.
+}
+
+void logical_op_from_macro_body(unsigned i) {
+ macro_op_parentheses_check_ops_body(i, i, i); // logical_op_parentheses_check-warning {{'&&' within '||'}} \
+ // logical_op_parentheses_check-note {{place parentheses around the '&&' expression to silence this warning}}
+}
\ No newline at end of file
Index: lib/Sema/SemaExpr.cpp
===================================================================
--- lib/Sema/SemaExpr.cpp
+++ lib/Sema/SemaExpr.cpp
@@ -12172,7 +12172,7 @@
EmitDiagnosticForLogicalAndInLogicalOr(Sema &Self, SourceLocation OpLoc,
BinaryOperator *Bop) {
assert(Bop->getOpcode() == BO_LAnd);
- Self.Diag(Bop->getOperatorLoc(), diag::warn_logical_and_in_logical_or)
+ Self.Diag(Bop->getOperatorLoc(), diag::warn_logical_and_in_logical_or)
<< Bop->getSourceRange() << OpLoc;
SuggestParentheses(Self, Bop->getOperatorLoc(),
Self.PDiag(diag::note_precedence_silence)
@@ -12205,6 +12205,7 @@
if (EvaluatesAsFalse(S, RHSExpr))
return;
// If it's "1 && a || b" don't warn since the precedence doesn't matter.
+ // And 'assert("some message" && a || b)' don't warn as well.
if (!EvaluatesAsTrue(S, Bop->getLHS()))
return EmitDiagnosticForLogicalAndInLogicalOr(S, OpLoc, Bop);
} else if (Bop->getOpcode() == BO_LOr) {
@@ -12227,6 +12228,7 @@
if (EvaluatesAsFalse(S, LHSExpr))
return;
// If it's "a || b && 1" don't warn since the precedence doesn't matter.
+ // And 'assert(a || b && "some message")' don't warn as well.
if (!EvaluatesAsTrue(S, Bop->getRHS()))
return EmitDiagnosticForLogicalAndInLogicalOr(S, OpLoc, Bop);
}
@@ -12309,8 +12311,16 @@
}
// Warn about arg1 || arg2 && arg3, as GCC 4.3+ does.
- // We don't warn for 'assert(a || b && "bad")' since this is safe.
- if (Opc == BO_LOr && !OpLoc.isMacroID()/* Don't warn in macros. */) {
+ // Here we will not skip 'logical and in logical or' checking
+ // in macros, since 'assert(a || b && "some message")' is equal
+ // to '(a || b && 1)' and 'assert("some message" && a || b)' is
+ // equal to '(1 && a || b)'.
+ if (Opc == BO_LOr &&
+ !Self.getSourceManager().isMacroArgExpansion(OpLoc)) {
+ // FIXME: we need a smarter parentheses checker to prevent emit
+ // useless warnings when logical operator comes from macro
+ // arguments like:
+ // #define DOUBLE_OP(OP1, OP2, X, Y, Z) (X OP1 Y OP2 Z)
DiagnoseLogicalAndInLogicalOrLHS(Self, OpLoc, LHSExpr, RHSExpr);
DiagnoseLogicalAndInLogicalOrRHS(Self, OpLoc, LHSExpr, RHSExpr);
}
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