Let pack_count helper variables be zero-indexed.

Author: adrian-prantl

lib/IRGen/IRGenDebugInfo.cpp

@@ -3000,7 +3000,8 @@ void IRGenDebugInfoImpl::emitPackCountParameter(IRGenFunction &IGF,
   if (!DS || DS->getInlinedFunction()->isTransparent())
     return;
 
-  Type IntTy = IGM.Context.getIntType();
+  Type IntTy = BuiltinIntegerType::get(CI.getTargetInfo().getPointerWidth(0),
+                                       IGM.getSwiftModule()->getASTContext());
   auto &TI = IGM.getTypeInfoForUnlowered(IntTy);
   auto DbgTy = *CompletedDebugTypeInfo::getFromTypeInfo(IntTy, TI, IGM);
   emitVariableDeclaration(

lib/IRGen/IRGenSIL.cpp

@@ -1105,7 +1105,7 @@ class IRGenSILFunction :
           if (PackShapeExpressions.insert(Shape).second) {
               llvm::SmallString<8> Buf;
               llvm::raw_svector_ostream OS(Buf);
-              unsigned Position = PackShapeExpressions.size();
+              unsigned Position = PackShapeExpressions.size() - 1;
               OS << "$pack_count_" << Position;
               SILDebugVariable Var(OS.str(), true, 0);
               Shape = emitShadowCopyIfNeeded(Shape, getDebugScope(), Var, false,

test/DebugInfo/variadic-generics-count.swift

@@ -36,9 +36,9 @@ public func f4<each U, each V>(us: repeat (each U, each V)) {
 }
 
 // CHECK-LABEL: !DICompileUnit
-// CHECK-DAG: [[COUNT1_1_VAR]] = !DILocalVariable(name: "$pack_count_1",{{.*}} flags: DIFlagArtificial)
-// CHECK-DAG: [[COUNT2_1_VAR]] = !DILocalVariable(name: "$pack_count_1",{{.*}} flags: DIFlagArtificial)
-// CHECK-DAG: [[COUNT2_2_VAR]] = !DILocalVariable(name: "$pack_count_2",{{.*}} flags: DIFlagArtificial)
-// CHECK-DAG: [[COUNT3_1_VAR]] = !DILocalVariable(name: "$pack_count_1",{{.*}} flags: DIFlagArtificial)
-// CHECK-DAG: [[COUNT4_1_VAR]] = !DILocalVariable(name: "$pack_count_1",{{.*}} flags: DIFlagArtificial)
+// CHECK-DAG: [[COUNT1_1_VAR]] = !DILocalVariable(name: "$pack_count_0",{{.*}} flags: DIFlagArtificial)
+// CHECK-DAG: [[COUNT2_1_VAR]] = !DILocalVariable(name: "$pack_count_0",{{.*}} flags: DIFlagArtificial)
+// CHECK-DAG: [[COUNT2_2_VAR]] = !DILocalVariable(name: "$pack_count_1",{{.*}} flags: DIFlagArtificial)
+// CHECK-DAG: [[COUNT3_1_VAR]] = !DILocalVariable(name: "$pack_count_0",{{.*}} flags: DIFlagArtificial)
+// CHECK-DAG: [[COUNT4_1_VAR]] = !DILocalVariable(name: "$pack_count_0",{{.*}} flags: DIFlagArtificial)