[IR] Make getParamAttributes take argument numbers, not ArgNo+1

Add hasParamAttribute() and use it instead of hasAttribute(ArgNo+1,
Kind) everywhere.

The fact that the AttributeList index for an argument is ArgNo+1 should
be a hidden implementation detail.

NFC

llvm-svn: 300272
diff --git a/llvm/lib/Transforms/IPO/ArgumentPromotion.cpp b/llvm/lib/Transforms/IPO/ArgumentPromotion.cpp
index 940c1ea..a2c8a32 100644
--- a/llvm/lib/Transforms/IPO/ArgumentPromotion.cpp
+++ b/llvm/lib/Transforms/IPO/ArgumentPromotion.cpp
@@ -106,7 +106,7 @@
   AttributeList PAL = F->getAttributes();
 
   // First, determine the new argument list
-  unsigned ArgIndex = 1;
+  unsigned ArgIndex = 0;
   for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end(); I != E;
        ++I, ++ArgIndex) {
     if (ByValArgsToTransform.count(&*I)) {
diff --git a/llvm/lib/Transforms/IPO/DeadArgumentElimination.cpp b/llvm/lib/Transforms/IPO/DeadArgumentElimination.cpp
index f0d987b..375b74c 100644
--- a/llvm/lib/Transforms/IPO/DeadArgumentElimination.cpp
+++ b/llvm/lib/Transforms/IPO/DeadArgumentElimination.cpp
@@ -698,8 +698,8 @@
     if (LiveValues.erase(Arg)) {
       Params.push_back(I->getType());
       ArgAlive[i] = true;
-      ArgAttrVec.push_back(PAL.getParamAttributes(i + 1));
-      HasLiveReturnedArg |= PAL.hasAttribute(i + 1, Attribute::Returned);
+      ArgAttrVec.push_back(PAL.getParamAttributes(i));
+      HasLiveReturnedArg |= PAL.hasParamAttribute(i, Attribute::Returned);
     } else {
       ++NumArgumentsEliminated;
       DEBUG(dbgs() << "DeadArgumentEliminationPass - Removing argument " << i
@@ -836,7 +836,7 @@
       if (ArgAlive[i]) {
         Args.push_back(*I);
         // Get original parameter attributes, but skip return attributes.
-        AttributeSet Attrs = CallPAL.getParamAttributes(i + 1);
+        AttributeSet Attrs = CallPAL.getParamAttributes(i);
         if (NRetTy != RetTy && Attrs.hasAttribute(Attribute::Returned)) {
           // If the return type has changed, then get rid of 'returned' on the
           // call site. The alternative is to make all 'returned' attributes on
@@ -855,7 +855,7 @@
     // Push any varargs arguments on the list. Don't forget their attributes.
     for (CallSite::arg_iterator E = CS.arg_end(); I != E; ++I, ++i) {
       Args.push_back(*I);
-      ArgAttrVec.push_back(CallPAL.getParamAttributes(i + 1));
+      ArgAttrVec.push_back(CallPAL.getParamAttributes(i));
     }
 
     // Reconstruct the AttributesList based on the vector we constructed.
diff --git a/llvm/lib/Transforms/IPO/MergeFunctions.cpp b/llvm/lib/Transforms/IPO/MergeFunctions.cpp
index 4ce4de1..771770d 100644
--- a/llvm/lib/Transforms/IPO/MergeFunctions.cpp
+++ b/llvm/lib/Transforms/IPO/MergeFunctions.cpp
@@ -432,19 +432,15 @@
       // Transferring other attributes may help other optimizations, but that
       // should be done uniformly and not in this ad-hoc way.
       auto &Context = New->getContext();
-      auto NewFuncAttrs = New->getAttributes();
-      auto CallSiteAttrs = CS.getAttributes();
-
-      CallSiteAttrs = CallSiteAttrs.addAttributes(
-          Context, AttributeList::ReturnIndex, NewFuncAttrs.getRetAttributes());
-
-      for (unsigned argIdx = 0; argIdx < CS.arg_size(); argIdx++) {
-        AttributeSet Attrs = NewFuncAttrs.getParamAttributes(argIdx);
-        if (Attrs.hasAttributes())
-          CallSiteAttrs = CallSiteAttrs.addAttributes(Context, argIdx, Attrs);
-      }
-
-      CS.setAttributes(CallSiteAttrs);
+      auto NewPAL = New->getAttributes();
+      SmallVector<AttributeSet, 4> NewArgAttrs;
+      for (unsigned argIdx = 0; argIdx < CS.arg_size(); argIdx++)
+        NewArgAttrs.push_back(NewPAL.getParamAttributes(argIdx));
+      // Don't transfer attributes from the function to the callee. Function
+      // attributes typically aren't relevant to the calling convention or ABI.
+      CS.setAttributes(AttributeList::get(Context, /*FnAttrs=*/AttributeSet(),
+                                          NewPAL.getRetAttributes(),
+                                          NewArgAttrs));
 
       remove(CS.getInstruction()->getParent()->getParent());
       U->set(BitcastNew);
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
index 47206cc..f17e003 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -3992,8 +3992,8 @@
     if (!CastInst::isBitOrNoopPointerCastable(ActTy, ParamTy, DL))
       return false;   // Cannot transform this parameter value.
 
-    if (AttrBuilder(CallerPAL.getParamAttributes(i + 1)).
-          overlaps(AttributeFuncs::typeIncompatible(ParamTy)))
+    if (AttrBuilder(CallerPAL.getParamAttributes(i))
+            .overlaps(AttributeFuncs::typeIncompatible(ParamTy)))
       return false;   // Attribute not compatible with transformed value.
 
     if (CS.isInAllocaArgument(i))
@@ -4001,7 +4001,7 @@
 
     // If the parameter is passed as a byval argument, then we have to have a
     // sized type and the sized type has to have the same size as the old type.
-    if (ParamTy != ActTy && CallerPAL.hasAttribute(i + 1, Attribute::ByVal)) {
+    if (ParamTy != ActTy && CallerPAL.hasParamAttribute(i, Attribute::ByVal)) {
       PointerType *ParamPTy = dyn_cast<PointerType>(ParamTy);
       if (!ParamPTy || !ParamPTy->getElementType()->isSized())
         return false;
@@ -4076,7 +4076,7 @@
     Args.push_back(NewArg);
 
     // Add any parameter attributes.
-    ArgAttrs.push_back(CallerPAL.getParamAttributes(i + 1));
+    ArgAttrs.push_back(CallerPAL.getParamAttributes(i));
   }
 
   // If the function takes more arguments than the call was taking, add them
@@ -4103,7 +4103,7 @@
         Args.push_back(NewArg);
 
         // Add any parameter attributes.
-        ArgAttrs.push_back(CallerPAL.getParamAttributes(i + 1));
+        ArgAttrs.push_back(CallerPAL.getParamAttributes(i));
       }
     }
   }
@@ -4202,19 +4202,22 @@
 
   AttributeList NestAttrs = NestF->getAttributes();
   if (!NestAttrs.isEmpty()) {
-    unsigned NestIdx = 1;
+    unsigned NestArgNo = 0;
     Type *NestTy = nullptr;
     AttributeSet NestAttr;
 
     // Look for a parameter marked with the 'nest' attribute.
     for (FunctionType::param_iterator I = NestFTy->param_begin(),
-         E = NestFTy->param_end(); I != E; ++NestIdx, ++I)
-      if (NestAttrs.hasAttribute(NestIdx, Attribute::Nest)) {
+                                      E = NestFTy->param_end();
+         I != E; ++NestArgNo, ++I) {
+      AttributeSet AS = NestAttrs.getParamAttributes(NestArgNo);
+      if (AS.hasAttribute(Attribute::Nest)) {
         // Record the parameter type and any other attributes.
         NestTy = *I;
-        NestAttr = NestAttrs.getParamAttributes(NestIdx);
+        NestAttr = AS;
         break;
       }
+    }
 
     if (NestTy) {
       Instruction *Caller = CS.getInstruction();
@@ -4227,10 +4230,10 @@
       // mean appending it.  Likewise for attributes.
 
       {
-        unsigned Idx = 1;
+        unsigned ArgNo = 0;
         CallSite::arg_iterator I = CS.arg_begin(), E = CS.arg_end();
         do {
-          if (Idx == NestIdx) {
+          if (ArgNo == NestArgNo) {
             // Add the chain argument and attributes.
             Value *NestVal = Tramp->getArgOperand(2);
             if (NestVal->getType() != NestTy)
@@ -4244,9 +4247,9 @@
 
           // Add the original argument and attributes.
           NewArgs.push_back(*I);
-          NewArgAttrs.push_back(Attrs.getParamAttributes(Idx));
+          NewArgAttrs.push_back(Attrs.getParamAttributes(ArgNo));
 
-          ++Idx;
+          ++ArgNo;
           ++I;
         } while (true);
       }
@@ -4261,12 +4264,12 @@
       // Insert the chain's type into the list of parameter types, which may
       // mean appending it.
       {
-        unsigned Idx = 1;
+        unsigned ArgNo = 0;
         FunctionType::param_iterator I = FTy->param_begin(),
           E = FTy->param_end();
 
         do {
-          if (Idx == NestIdx)
+          if (ArgNo == NestArgNo)
             // Add the chain's type.
             NewTypes.push_back(NestTy);
 
@@ -4276,7 +4279,7 @@
           // Add the original type.
           NewTypes.push_back(*I);
 
-          ++Idx;
+          ++ArgNo;
           ++I;
         } while (true);
       }
diff --git a/llvm/lib/Transforms/Utils/CloneFunction.cpp b/llvm/lib/Transforms/Utils/CloneFunction.cpp
index 0577026..385c123 100644
--- a/llvm/lib/Transforms/Utils/CloneFunction.cpp
+++ b/llvm/lib/Transforms/Utils/CloneFunction.cpp
@@ -110,7 +110,7 @@
   for (const Argument &OldArg : OldFunc->args()) {
     if (Argument *NewArg = dyn_cast<Argument>(VMap[&OldArg])) {
       NewArgAttrs[NewArg->getArgNo()] =
-          OldAttrs.getParamAttributes(OldArg.getArgNo() + 1);
+          OldAttrs.getParamAttributes(OldArg.getArgNo());
     }
   }