Suppress -Warray-bounds in certain cases involving macros from system headers.
The motivation here is a "clever" implementation of strncmp(), which peels the first few comparisons via chained conditional expressions which ensure that the input arrays are known at compile time to be sufficiently large.
llvm-svn: 146430
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index 1c93931..bb567d0 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -4275,7 +4275,7 @@
void Sema::CheckArrayAccess(const Expr *BaseExpr, const Expr *IndexExpr,
bool isSubscript, bool AllowOnePastEnd) {
- const Type* EffectiveType = getElementType(BaseExpr);
+ const Type *EffectiveType = getElementType(BaseExpr);
BaseExpr = BaseExpr->IgnoreParenCasts();
IndexExpr = IndexExpr->IgnoreParenCasts();
@@ -4381,6 +4381,16 @@
switch (expr->getStmtClass()) {
case Stmt::ArraySubscriptExprClass: {
const ArraySubscriptExpr *ASE = cast<ArraySubscriptExpr>(expr);
+ // Suppress the warning if the subscript expression (as identified by
+ // the ']' location) and the index expression are both from macro
+ // expansions within a system header.
+ SourceLocation RBracketLoc = SourceMgr.getSpellingLoc(
+ ASE->getRBracketLoc());
+ SourceLocation IndexLoc = SourceMgr.getSpellingLoc(
+ ASE->getIdx()->IgnoreParens()->getLocStart());
+ if (SourceMgr.isFromSameFile(RBracketLoc, IndexLoc) &&
+ SourceMgr.isInSystemHeader(RBracketLoc))
+ return;
CheckArrayAccess(ASE->getBase(), ASE->getIdx(), true,
AllowOnePastEnd > 0);
return;