<div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">On 21 March 2017 at 12:01, Aaron Ballman via cfe-commits <span dir="ltr"><<a href="mailto:cfe-commits@lists.llvm.org" target="_blank">cfe-commits@lists.llvm.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Author: aaronballman<br>
Date: Tue Mar 21 14:01:17 2017<br>
New Revision: 298421<br>
<br>
URL: <a href="http://llvm.org/viewvc/llvm-project?rev=298421&view=rev" rel="noreferrer" target="_blank">http://llvm.org/viewvc/llvm-<wbr>project?rev=298421&view=rev</a><br>
Log:<br>
Prevent cppcoreguidelines-pro-bounds-<wbr>array-to-pointer-decay from diagnosing array to pointer decay stemming from system macros.<br>
<br>
Patch by Breno Rodrigues Guimaraes.<br>
<br>
Modified:<br>
clang-tools-extra/trunk/clang-<wbr>tidy/cppcoreguidelines/<wbr>ProBoundsArrayToPointerDecayCh<wbr>eck.cpp<br>
clang-tools-extra/trunk/test/<wbr>clang-tidy/cppcoreguidelines-<wbr>pro-bounds-array-to-pointer-<wbr>decay.cpp<br>
<br>
Modified: clang-tools-extra/trunk/clang-<wbr>tidy/cppcoreguidelines/<wbr>ProBoundsArrayToPointerDecayCh<wbr>eck.cpp<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/clang-tidy/cppcoreguidelines/ProBoundsArrayToPointerDecayCheck.cpp?rev=298421&r1=298420&r2=298421&view=diff" rel="noreferrer" target="_blank">http://llvm.org/viewvc/llvm-<wbr>project/clang-tools-extra/<wbr>trunk/clang-tidy/<wbr>cppcoreguidelines/<wbr>ProBoundsArrayToPointerDecayCh<wbr>eck.cpp?rev=298421&r1=298420&<wbr>r2=298421&view=diff</a><br>
==============================<wbr>==============================<wbr>==================<br>
--- clang-tools-extra/trunk/clang-<wbr>tidy/cppcoreguidelines/<wbr>ProBoundsArrayToPointerDecayCh<wbr>eck.cpp (original)<br>
+++ clang-tools-extra/trunk/clang-<wbr>tidy/cppcoreguidelines/<wbr>ProBoundsArrayToPointerDecayCh<wbr>eck.cpp Tue Mar 21 14:01:17 2017<br>
@@ -47,6 +47,25 @@ AST_MATCHER_P(Expr, hasParentIgnoringImp<br>
return InnerMatcher.matches(*E, Finder, Builder);<br>
}<br>
<br>
+AST_MATCHER(ImplicitCastExpr, isArrayToPointerDecay) {<br>
+ return Node.getCastKind() == CK_ArrayToPointerDecay;<br>
+}<br>
+<br>
+AST_MATCHER(ImplicitCastExpr, sysSymbolDecayInSysHeader) {<br>
+ auto &SM = Finder->getASTContext().<wbr>getSourceManager();<br>
+ if (SM.isInSystemMacro(Node.<wbr>getLocStart())) {<br>
+ if (isa<PredefinedExpr>(Node.<wbr>getSubExpr()))<br>
+ return true;<br>
+<br>
+ if (const auto *SymbolDeclRef = dyn_cast<DeclRefExpr>(Node.<wbr>getSubExpr())) {<br>
+ const ValueDecl *SymbolDecl = SymbolDeclRef->getDecl();<br>
+ if (SymbolDecl && SM.isInSystemHeader(<wbr>SymbolDecl->getLocation()))<br>
+ return true;<br>
+ }<br>
+ }<br>
+ return false;<br>
+}<br>
+<br>
void ProBoundsArrayToPointerDecayCh<wbr>eck::registerMatchers(<wbr>MatchFinder *Finder) {<br>
if (!getLangOpts().CPlusPlus)<br>
return;<br>
@@ -56,10 +75,12 @@ void ProBoundsArrayToPointerDecayCh<wbr>eck::<br>
// 2) inside a range-for over an array<br>
// 3) if it converts a string literal to a pointer<br>
Finder->addMatcher(<br>
- implicitCastExpr(unless(<wbr>hasParent(arraySubscriptExpr()<wbr>)),<br>
+ implicitCastExpr(<wbr>isArrayToPointerDecay(),<br>
+ unless(hasParent(<wbr>arraySubscriptExpr())),<br>
unless(<wbr>hasParentIgnoringImpCasts(<wbr>explicitCastExpr())),<br>
unless(<wbr>isInsideOfRangeBeginEndStmt())<wbr>,<br>
- unless(hasSourceExpression(<wbr>stringLiteral())))<br>
+ unless(hasSourceExpression(<wbr>stringLiteral())),<br>
+ unless(<wbr>sysSymbolDecayInSysHeader()))<br>
.bind("cast"),<br>
this);<br>
}<br>
@@ -67,8 +88,6 @@ void ProBoundsArrayToPointerDecayCh<wbr>eck::<br>
void ProBoundsArrayToPointerDecayCh<wbr>eck::check(<br>
const MatchFinder::MatchResult &Result) {<br>
const auto *MatchedCast = Result.Nodes.getNodeAs<<wbr>ImplicitCastExpr>("cast");<br>
- if (MatchedCast->getCastKind() != CK_ArrayToPointerDecay)<br>
- return;<br>
<br>
diag(MatchedCast->getExprLoc()<wbr>, "do not implicitly decay an array into a "<br>
"pointer; consider using gsl::array_view or "<br>
<br>
Modified: clang-tools-extra/trunk/test/<wbr>clang-tidy/cppcoreguidelines-<wbr>pro-bounds-array-to-pointer-<wbr>decay.cpp<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/test/clang-tidy/cppcoreguidelines-pro-bounds-array-to-pointer-decay.cpp?rev=298421&r1=298420&r2=298421&view=diff" rel="noreferrer" target="_blank">http://llvm.org/viewvc/llvm-<wbr>project/clang-tools-extra/<wbr>trunk/test/clang-tidy/<wbr>cppcoreguidelines-pro-bounds-<wbr>array-to-pointer-decay.cpp?<wbr>rev=298421&r1=298420&r2=<wbr>298421&view=diff</a><br>
==============================<wbr>==============================<wbr>==================<br>
--- clang-tools-extra/trunk/test/<wbr>clang-tidy/cppcoreguidelines-<wbr>pro-bounds-array-to-pointer-<wbr>decay.cpp (original)<br>
+++ clang-tools-extra/trunk/test/<wbr>clang-tidy/cppcoreguidelines-<wbr>pro-bounds-array-to-pointer-<wbr>decay.cpp Tue Mar 21 14:01:17 2017<br>
@@ -1,4 +1,5 @@<br>
// RUN: %check_clang_tidy %s cppcoreguidelines-pro-bounds-<wbr>array-to-pointer-decay %t<br>
+#include <assert.h><br></blockquote><div><br></div><div>This test is using a header that we do not supply (unlike stddef.h which Clang provides itself). That does not seem especially reasonable to me; this test is failing for us as a result. Can you supply a fake <assert.h> system header as an input to this test?</div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
#include <stddef.h><br>
<br>
namespace gsl {<br>
@@ -34,6 +35,11 @@ void f() {<br>
<br>
for (auto &e : a) // OK, iteration internally decays array to pointer<br>
e = 1;<br>
+<br>
+ assert(false); // OK, array decay inside system header macro<br></blockquote><div><br></div><div>Huh? What decay is this referring to?</div><div><br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
+<br>
+ assert(a);<br>
+ // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: do not implicitly decay an array into a pointer; consider using gsl::array_view or an explicit cast instead [cppcoreguidelines-pro-bounds-<wbr>array-to-pointer-decay]<br>
}<br>
<br>
const char *g() {<br>
<br>
<br>
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</blockquote></div><br></div></div>