stdlib: rename x86_64 variables to be generic

Rename some of the variables in the VaListBuilder path to be agnostic to
the architecture.  SSE is x86 specific, by renaming the variables to
hide the fact that the path is x86 specific, we will be able to share
some of the code with arm64 (where the analogous hardware is the VFP).

Author: compnerd

stdlib/public/core/VarArgs.swift

@@ -80,11 +80,11 @@ internal let _countGPRegisters = 6
 // from 8 to 16 based on reading the spec, probably the bug you're looking for
 // is elsewhere.
 @usableFromInline
-internal let _countSSERegisters = 8
+internal let _countFPRegisters = 8
 @usableFromInline
-internal let _sseRegisterWords = 2
+internal let _fpRegisterWords = 2
 @usableFromInline
-internal let _registerSaveWords = _countGPRegisters + _countSSERegisters * _sseRegisterWords
+internal let _registerSaveWords = _countGPRegisters + _countFPRegisters * _fpRegisterWords
 #elseif arch(s390x)
 @usableFromInline
 internal let _countGPRegisters = 16
@@ -424,14 +424,14 @@ final internal class _VaListBuilder {
 #if arch(x86_64)
     let isDouble = arg is _CVarArgPassedAsDouble
 
-    if isDouble && sseRegistersUsed < _countSSERegisters {
+    if isDouble && fpRegistersUsed < _countFPRegisters {
       var startIndex = _countGPRegisters
-           + (sseRegistersUsed * _sseRegisterWords)
+           + (fpRegistersUsed * _fpRegisterWords)
       for w in encoded {
         storage[startIndex] = w
         startIndex += 1
       }
-      sseRegistersUsed += 1
+      fpRegistersUsed += 1
     }
     else if encoded.count == 1
       && !isDouble
@@ -472,7 +472,7 @@ final internal class _VaListBuilder {
   @usableFromInline // FIXME(sil-serialize-all)
   internal var gpRegistersUsed = 0
   @usableFromInline // FIXME(sil-serialize-all)
-  internal var sseRegistersUsed = 0
+  internal var fpRegistersUsed = 0
 
   @usableFromInline // FIXME(sil-serialize-all)
   final  // Property must be final since it is used by Builtin.addressof.

test/api-digester/Inputs/stdlib-stable-abi.json

@@ -242778,8 +242778,8 @@
     },
     {
       "kind": "Var",
-      "name": "_countSSERegisters",
-      "printedName": "_countSSERegisters",
+      "name": "_countFPRegisters",
+      "printedName": "_countFPRegisters",
       "children": [
         {
           "kind": "TypeNominal",
@@ -242800,13 +242800,13 @@
             }
           ],
           "declKind": "Accessor",
-          "usr": "s:s18_countSSERegistersSivg",
+          "usr": "s:s17_countFPRegistersSivg",
           "moduleName": "Swift",
           "implicit": true
         }
       ],
       "declKind": "Var",
-      "usr": "s:s18_countSSERegistersSivp",
+      "usr": "s:s17_countFPRegistersSivp",
       "moduleName": "Swift",
       "declAttributes": [
         "HasInitialValue",
@@ -242817,8 +242817,8 @@
     },
     {
       "kind": "Var",
-      "name": "_sseRegisterWords",
-      "printedName": "_sseRegisterWords",
+      "name": "_fpRegisterWords",
+      "printedName": "_fpRegisterWords",
       "children": [
         {
           "kind": "TypeNominal",
@@ -242839,13 +242839,13 @@
             }
           ],
           "declKind": "Accessor",
-          "usr": "s:s17_sseRegisterWordsSivg",
+          "usr": "s:s16_fpRegisterWordsSivg",
           "moduleName": "Swift",
           "implicit": true
         }
       ],
       "declKind": "Var",
-      "usr": "s:s17_sseRegisterWordsSivp",
+      "usr": "s:s16_fpRegisterWordsSivp",
       "moduleName": "Swift",
       "declAttributes": [
         "HasInitialValue",
@@ -243445,8 +243445,8 @@
         },
         {
           "kind": "Var",
-          "name": "sseRegistersUsed",
-          "printedName": "sseRegistersUsed",
+          "name": "fpRegistersUsed",
+          "printedName": "fpRegistersUsed",
           "children": [
             {
               "kind": "TypeNominal",
@@ -243467,7 +243467,7 @@
                 }
               ],
               "declKind": "Accessor",
-              "usr": "s:s14_VaListBuilderC16sseRegistersUsedSivg",
+              "usr": "s:s14_VaListBuilderC16fpRegistersUsedSivg",
               "moduleName": "Swift",
               "implicit": true,
               "declAttributes": [
@@ -243477,7 +243477,7 @@
             }
           ],
           "declKind": "Var",
-          "usr": "s:s14_VaListBuilderC16sseRegistersUsedSivp",
+          "usr": "s:s14_VaListBuilderC15fpRegistersUsedSivp",
           "moduleName": "Swift",
           "declAttributes": [
             "Final",
@@ -244158,4 +244158,4 @@
       "isInternal": true
     }
   ]
-}
+}