Fix PR20069: bad loop pragma arguments crash FE

This patch fixes a crash when handling malformed arguments to loop pragmas such
as: "#pragma clang loop vectorize(()".  Essentially any argument which is not an
identifier or constant resulted in a crash.  This patch also changes a couple of
the error messages which weren't quite correct.  New behavior with this patch vs
old behavior:

#pragma clang loop vectorize(1)
OLD: error: missing keyword; expected 'enable' or 'disable'
NEW: error: invalid argument; expected 'enable' or 'disable'

#pragma clang loop vectorize()
OLD: error: expected ')'
NEW: error: missing argument to loop pragma 'vectorize'

#pragma clang loop vectorize_width(bad)
OLD: error: missing value; expected a positive integer value
NEW: error: invalid argument; expected a positive integer value

#pragma clang loop vectorize(bad)
OLD: invalid keyword 'bad'; expected 'enable' or 'disable'
NEW: error: invalid argument; expected 'enable' or 'disable'

http://reviews.llvm.org/D4197

Patch by Mark Heffernan

llvm-svn: 211292

1 files changed, 5 insertions, 14 deletions

diff --git a/clang/lib/Sema/SemaStmtAttr.cpp b/clang/lib/Sema/SemaStmtAttr.cpp
index c0b5ede526c..44169c2fdce 100644
--- a/clang/lib/Sema/SemaStmtAttr.cpp
+++ b/clang/lib/Sema/SemaStmtAttr.cpp
@@ -75,18 +75,15 @@ static Attr *handleLoopHintAttr(Sema &S, Stmt *St, const AttributeList &A,
   if (Option == LoopHintAttr::Vectorize || Option == LoopHintAttr::Interleave ||
       Option == LoopHintAttr::Unroll) {
     if (!ValueInfo) {
-      S.Diag(ValueLoc->Loc, diag::err_pragma_loop_invalid_keyword)
-          << /*MissingKeyword=*/true << "";
+      S.Diag(ValueLoc->Loc, diag::err_pragma_loop_invalid_keyword);
       return nullptr;
     }
-
     if (ValueInfo->isStr("disable"))
       ValueInt = 0;
     else if (ValueInfo->isStr("enable"))
       ValueInt = 1;
     else {
-      S.Diag(ValueLoc->Loc, diag::err_pragma_loop_invalid_keyword)
-          << /*MissingKeyword=*/false << ValueInfo;
+      S.Diag(ValueLoc->Loc, diag::err_pragma_loop_invalid_keyword);
       return nullptr;
     }
   } else if (Option == LoopHintAttr::VectorizeWidth ||
@@ -95,15 +92,9 @@ static Attr *handleLoopHintAttr(Sema &S, Stmt *St, const AttributeList &A,
     // FIXME: We should support template parameters for the loop hint value.
     // See bug report #19610.
     llvm::APSInt ValueAPS;
-    if (!ValueExpr || !ValueExpr->isIntegerConstantExpr(ValueAPS, S.Context)) {
-      S.Diag(ValueLoc->Loc, diag::err_pragma_loop_invalid_value)
-          << /*MissingValue=*/true << "";
-      return nullptr;
-    }
-
-    if ((ValueInt = ValueAPS.getSExtValue()) < 1) {
-      S.Diag(ValueLoc->Loc, diag::err_pragma_loop_invalid_value)
-          << /*MissingValue=*/false << ValueInt;
+    if (!ValueExpr || !ValueExpr->isIntegerConstantExpr(ValueAPS, S.Context) ||
+        (ValueInt = ValueAPS.getSExtValue()) < 1) {
+      S.Diag(ValueLoc->Loc, diag::err_pragma_loop_invalid_value);
       return nullptr;
     }
   } else