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[clang-tidy] fix PR36489 - respect deduced pointer types from auto as well 

Summary:
The cppcoreguidelines-pro-bounds-pointer-arithmetic warns on all occassion where
pointer arithmetic is used, but does not check values where the pointer types
is deduced via `auto`. This patch adjusts this behaviour and solved
PR36489.
I accidentally commited a wrong patch, this Differential is meant to have a
correct revision description and code attached to it.
Because the patch was accepted by aaron.ballman already, i will just commit
it.
See https://reviews.llvm.org/D48717 for the old differntial (contains wrong
code from the mixup)

Subscribers: nemanjai, xazax.hun, kbarton, cfe-commits

Differential Revision: https://reviews.llvm.org/D49682

llvm-svn: 337716
This commit is contained in:
Jonas Toth 2018-07-23 17:46:17 +00:00
parent dbc390d0c5
commit ad2524f9fc
2 changed files with 59 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsPointerArithmeticCheck.cpp
View File

@ -21,12 +21,16 @@ void ProBoundsPointerArithmeticCheck::registerMatchers(MatchFinder *Finder) {
if (!getLangOpts().CPlusPlus)
return;
const auto AllPointerTypes = anyOf(
hasType(pointerType()), hasType(autoType(hasDeducedType(pointerType()))),
hasType(decltypeType(hasUnderlyingType(pointerType()))));
// Flag all operators +, -, +=, -=, ++, -- that result in a pointer
Finder->addMatcher(
binaryOperator(
anyOf(hasOperatorName("+"), hasOperatorName("-"),
hasOperatorName("+="), hasOperatorName("-=")),
hasType(pointerType()),
AllPointerTypes,
unless(hasLHS(ignoringImpCasts(declRefExpr(to(isImplicit()))))))
.bind("expr"),
this);
@ -41,7 +45,7 @@ void ProBoundsPointerArithmeticCheck::registerMatchers(MatchFinder *Finder) {
Finder->addMatcher(
arraySubscriptExpr(
hasBase(ignoringImpCasts(
anyOf(hasType(pointerType()),
anyOf(AllPointerTypes,
hasType(decayedType(hasDecayedType(pointerType())))))))
.bind("expr"),
this);

53
clang-tools-extra/test/clang-tidy/cppcoreguidelines-pro-bounds-pointer-arithmetic-pr36489.cpp Normal file
View File

@ -0,0 +1,53 @@
// RUN: %check_clang_tidy %s cppcoreguidelines-pro-bounds-pointer-arithmetic %t -- -- -std=c++14
// Fix PR36489 and detect auto-deduced value correctly.
char *getPtr();
auto getPtrAuto() { return getPtr(); }
decltype(getPtr()) getPtrDeclType();
decltype(auto) getPtrDeclTypeAuto() { return getPtr(); }
auto getPtrWithTrailingReturnType() -> char *;
void auto_deduction_binary() {
auto p1 = getPtr() + 1;
// CHECK-MESSAGES: :[[@LINE-1]]:22: warning: do not use pointer arithmetic
auto p2 = getPtrAuto() + 1;
// CHECK-MESSAGES: :[[@LINE-1]]:26: warning: do not use pointer arithmetic
auto p3 = getPtrWithTrailingReturnType() + 1;
// CHECK-MESSAGES: :[[@LINE-1]]:44: warning: do not use pointer arithmetic
auto p4 = getPtr();
auto *p5 = getPtr();
p4 = p4 + 1;
// CHECK-MESSAGES: :[[@LINE-1]]:11: warning: do not use pointer arithmetic
p5 = p5 + 1;
// CHECK-MESSAGES: :[[@LINE-1]]:11: warning: do not use pointer arithmetic
auto p6 = getPtrDeclType() + 1;
// CHECK-MESSAGES: :[[@LINE-1]]:30: warning: do not use pointer arithmetic
auto p7 = getPtrDeclTypeAuto() + 1;
// CHECK-MESSAGES: :[[@LINE-1]]:34: warning: do not use pointer arithmetic
auto *p8 = getPtrDeclType() + 1;
// CHECK-MESSAGES: :[[@LINE-1]]:31: warning: do not use pointer arithmetic
auto *p9 = getPtrDeclTypeAuto() + 1;
// CHECK-MESSAGES: :[[@LINE-1]]:35: warning: do not use pointer arithmetic
}
void auto_deduction_subscript() {
char p1 = getPtr()[2];
// CHECK-MESSAGES: :[[@LINE-1]]:13: warning: do not use pointer arithmetic
auto p2 = getPtr()[3];
// CHECK-MESSAGES: :[[@LINE-1]]:13: warning: do not use pointer arithmetic
char p3 = getPtrAuto()[4];
// CHECK-MESSAGES: :[[@LINE-1]]:13: warning: do not use pointer arithmetic
auto p4 = getPtrAuto()[5];
// CHECK-MESSAGES: :[[@LINE-1]]:13: warning: do not use pointer arithmetic
char p5 = getPtrWithTrailingReturnType()[6];
// CHECK-MESSAGES: :[[@LINE-1]]:13: warning: do not use pointer arithmetic
auto p6 = getPtrWithTrailingReturnType()[7];
// CHECK-MESSAGES: :[[@LINE-1]]:13: warning: do not use pointer arithmetic
auto p7 = getPtrDeclType()[8];
// CHECK-MESSAGES: :[[@LINE-1]]:13: warning: do not use pointer arithmetic
auto p8 = getPtrDeclTypeAuto()[9];
// CHECK-MESSAGES: :[[@LINE-1]]:13: warning: do not use pointer arithmetic
}