Reland "[Attr] Fix parameter indexing for several attributes"

Relands r326602 (reverted in r326862) with new test and fix for
PR36620.

Differential Revision: https://reviews.llvm.org/D43248

llvm-svn: 327405

1 files changed, 4 insertions, 6 deletions

diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index 851a03aa2ed..84ac4daeef9 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -5475,9 +5475,8 @@ static bool getBytesReturnedByAllocSizeCall(const ASTContext &Ctx,
                                             llvm::APInt &Result) {
   const AllocSizeAttr *AllocSize = getAllocSizeAttr(Call);
 
-  // alloc_size args are 1-indexed, 0 means not present.
-  assert(AllocSize && AllocSize->getElemSizeParam() != 0);
-  unsigned SizeArgNo = AllocSize->getElemSizeParam() - 1;
+  assert(AllocSize && AllocSize->getElemSizeParam().isValid());
+  unsigned SizeArgNo = AllocSize->getElemSizeParam().getASTIndex();
   unsigned BitsInSizeT = Ctx.getTypeSize(Ctx.getSizeType());
   if (Call->getNumArgs() <= SizeArgNo)
     return false;
@@ -5495,14 +5494,13 @@ static bool getBytesReturnedByAllocSizeCall(const ASTContext &Ctx,
   if (!EvaluateAsSizeT(Call->getArg(SizeArgNo), SizeOfElem))
     return false;
 
-  if (!AllocSize->getNumElemsParam()) {
+  if (!AllocSize->getNumElemsParam().isValid()) {
     Result = std::move(SizeOfElem);
     return true;
   }
 
   APSInt NumberOfElems;
-  // Argument numbers start at 1
-  unsigned NumArgNo = AllocSize->getNumElemsParam() - 1;
+  unsigned NumArgNo = AllocSize->getNumElemsParam().getASTIndex();
   if (!EvaluateAsSizeT(Call->getArg(NumArgNo), NumberOfElems))
     return false;