danielmarjamaki set the repository for this revision to rL LLVM.
danielmarjamaki updated this revision to Diff 73633.
danielmarjamaki added a comment.
Add new flag : -Wshift-op-parentheses-mul
This is not enabled by default.
Repository:
rL LLVM
https://reviews.llvm.org/D24861
Files:
include/clang/Basic/DiagnosticSemaKinds.td
lib/Sema/SemaExpr.cpp
test/Sema/parentheses.cpp
Index: test/Sema/parentheses.cpp
===================================================================
--- test/Sema/parentheses.cpp
+++ test/Sema/parentheses.cpp
@@ -1,5 +1,5 @@
-// RUN: %clang_cc1 -Wparentheses -fsyntax-only -verify %s
-// RUN: %clang_cc1 -Wparentheses -fsyntax-only -fdiagnostics-parseable-fixits %s 2>&1 | FileCheck %s
+// RUN: %clang_cc1 -Wparentheses -Wshift-op-parentheses-mul -fsyntax-only -verify %s
+// RUN: %clang_cc1 -Wparentheses -Wshift-op-parentheses-mul -fsyntax-only -fdiagnostics-parseable-fixits %s 2>&1 | FileCheck %s
bool someConditionFunc();
@@ -95,6 +95,23 @@
// CHECK: fix-it:"{{.*}}":{[[@LINE-2]]:10-[[@LINE-2]]:10}:"("
// CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:15-[[@LINE-3]]:15}:")"
+ (void)(a >> b * c); // expected-warning {{operator '>>' has lower precedence than '*'; '*' will be evaluated first}} \
+ expected-note {{place parentheses around the '*' expression to silence this warning}}
+ // CHECK: fix-it:"{{.*}}":{[[@LINE-2]]:15-[[@LINE-2]]:15}:"("
+ // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:20-[[@LINE-3]]:20}:")"
+
+ (void)(a / b << c); // expected-warning {{operator '<<' has lower precedence than '/'; '/' will be evaluated first}} \
+ expected-note {{place parentheses around the '/' expression to silence this warning}}
+ // CHECK: fix-it:"{{.*}}":{[[@LINE-2]]:10-[[@LINE-2]]:10}:"("
+ // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:15-[[@LINE-3]]:15}:")"
+
+ (void)(a % b << c); // expected-warning {{operator '<<' has lower precedence than '%'; '%' will be evaluated first}} \
+ expected-note {{place parentheses around the '%' expression to silence this warning}}
+ // CHECK: fix-it:"{{.*}}":{[[@LINE-2]]:10-[[@LINE-2]]:10}:"("
+ // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:15-[[@LINE-3]]:15}:")"
+
+ (void)(a * b << c); // no warning, often the execution order does not matter.
+
Stream() << b + c;
Stream() >> b + c; // expected-warning {{operator '>>' has lower precedence than '+'; '+' will be evaluated first}} \
expected-note {{place parentheses around the '+' expression to silence this warning}}
Index: lib/Sema/SemaExpr.cpp
===================================================================
--- lib/Sema/SemaExpr.cpp
+++ lib/Sema/SemaExpr.cpp
@@ -11263,18 +11263,26 @@
}
}
-static void DiagnoseAdditionInShift(Sema &S, SourceLocation OpLoc,
- Expr *SubExpr, StringRef Shift) {
- if (BinaryOperator *Bop = dyn_cast<BinaryOperator>(SubExpr)) {
- if (Bop->getOpcode() == BO_Add || Bop->getOpcode() == BO_Sub) {
- StringRef Op = Bop->getOpcodeStr();
- S.Diag(Bop->getOperatorLoc(), diag::warn_addition_in_bitshift)
- << Bop->getSourceRange() << OpLoc << Shift << Op;
- SuggestParentheses(S, Bop->getOperatorLoc(),
- S.PDiag(diag::note_precedence_silence) << Op,
- Bop->getSourceRange());
- }
- }
+static void DiagnoseAddOrMulInShift(Sema &S, SourceLocation OpLoc,
+ Expr *SubExpr, StringRef Shift,
+ bool ShiftLeftLHS) {
+ BinaryOperator *Bop = dyn_cast<BinaryOperator>(SubExpr);
+ if (!Bop)
+ return;
+ if (!Bop->isAdditiveOp() && !Bop->isMultiplicativeOp())
+ return;
+ // In many cases, execution order does not matter for 'A*B<<C'.
+ if (ShiftLeftLHS && Bop->getOpcode() == BO_Mul)
+ return;
+
+ StringRef Op = Bop->getOpcodeStr();
+ S.Diag(Bop->getOperatorLoc(), Bop->isAdditiveOp()
+ ? diag::warn_addition_in_bitshift
+ : diag::warn_multiplication_in_bitshift)
+ << Bop->getSourceRange() << OpLoc << Shift << Op;
+ SuggestParentheses(S, Bop->getOperatorLoc(),
+ S.PDiag(diag::note_precedence_silence) << Op,
+ Bop->getSourceRange());
}
static void DiagnoseShiftCompare(Sema &S, SourceLocation OpLoc,
@@ -11330,8 +11338,8 @@
if ((Opc == BO_Shl && LHSExpr->getType()->isIntegralType(Self.getASTContext()))
|| Opc == BO_Shr) {
StringRef Shift = BinaryOperator::getOpcodeStr(Opc);
- DiagnoseAdditionInShift(Self, OpLoc, LHSExpr, Shift);
- DiagnoseAdditionInShift(Self, OpLoc, RHSExpr, Shift);
+ DiagnoseAddOrMulInShift(Self, OpLoc, LHSExpr, Shift, Opc == BO_Shl);
+ DiagnoseAddOrMulInShift(Self, OpLoc, RHSExpr, Shift, false);
}
// Warn on overloaded shift operators and comparisons, such as:
Index: include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- include/clang/Basic/DiagnosticSemaKinds.td
+++ include/clang/Basic/DiagnosticSemaKinds.td
@@ -5232,6 +5232,9 @@
def warn_addition_in_bitshift : Warning<
"operator '%0' has lower precedence than '%1'; "
"'%1' will be evaluated first">, InGroup<ShiftOpParentheses>;
+def warn_multiplication_in_bitshift : Warning<
+ "operator '%0' has lower precedence than '%1'; "
+ "'%1' will be evaluated first">, InGroup<DiagGroup<"shift-op-parentheses-mul">>, DefaultIgnore;
def warn_self_assignment : Warning<
"explicitly assigning value of variable of type %0 to itself">,
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