Add _pointerBitWidth platform condition (#41534)

* Add _pointerBitWidth platform condition

* Fixes after rebasing

---------

Co-authored-by: Xiaodi Wu <xiaodi.wu@gmail.com>

Author: drexin

include/swift/AST/PlatformConditionKinds.def

@@ -31,6 +31,9 @@ PLATFORM_CONDITION(Arch, "arch")
 /// The active endianness target (big or little)
 PLATFORM_CONDITION_(Endianness, "endian")
 
+/// The active arch target pointer bit width (_32 or _64)
+PLATFORM_CONDITION_(PointerBitWidth, "pointerBitWidth")
+
 /// Runtime support (_ObjC or _Native)
 PLATFORM_CONDITION_(Runtime, "runtime")
 

lib/Basic/LangOptions.cpp

@@ -84,6 +84,11 @@ static const SupportedConditionalValue SupportedConditionalCompilationEndianness
   "big"
 };
 
+static const SupportedConditionalValue SupportedConditionalCompilationPointerBitWidths[] = {
+  "_32",
+  "_64"
+};
+
 static const SupportedConditionalValue SupportedConditionalCompilationRuntimes[] = {
   "_ObjC",
   "_Native",
@@ -114,6 +119,8 @@ ArrayRef<SupportedConditionalValue> getSupportedConditionalCompilationValues(con
     return SupportedConditionalCompilationArches;
   case PlatformConditionKind::Endianness:
     return SupportedConditionalCompilationEndianness;
+  case PlatformConditionKind::PointerBitWidth:
+    return SupportedConditionalCompilationPointerBitWidths;
   case PlatformConditionKind::Runtime:
     return SupportedConditionalCompilationRuntimes;
   case PlatformConditionKind::CanImport:
@@ -181,6 +188,7 @@ checkPlatformConditionSupported(PlatformConditionKind Kind, StringRef Value,
   case PlatformConditionKind::OS:
   case PlatformConditionKind::Arch:
   case PlatformConditionKind::Endianness:
+  case PlatformConditionKind::PointerBitWidth:
   case PlatformConditionKind::Runtime:
   case PlatformConditionKind::TargetEnvironment:
   case PlatformConditionKind::PtrAuth:
@@ -405,6 +413,25 @@ std::pair<bool, bool> LangOptions::setTarget(llvm::Triple triple) {
     break;
   }
 
+  // Set the "_pointerBitWidth" platform condition.
+  switch (Target.getArch()) {
+  default: llvm_unreachable("undefined architecture pointer bit width");
+  case llvm::Triple::ArchType::arm:
+  case llvm::Triple::ArchType::thumb:
+  case llvm::Triple::ArchType::aarch64_32:
+  case llvm::Triple::ArchType::x86:
+  case llvm::Triple::ArchType::wasm32:
+    addPlatformConditionValue(PlatformConditionKind::PointerBitWidth, "_32");
+    break;
+  case llvm::Triple::ArchType::aarch64:
+  case llvm::Triple::ArchType::ppc64:
+  case llvm::Triple::ArchType::ppc64le:
+  case llvm::Triple::ArchType::x86_64:
+  case llvm::Triple::ArchType::systemz:
+    addPlatformConditionValue(PlatformConditionKind::PointerBitWidth, "_64");
+    break;
+  }
+
   // Set the "runtime" platform condition.
   addPlatformConditionValue(PlatformConditionKind::Runtime,
                             EnableObjCInterop ? "_ObjC" : "_Native");

lib/Parse/ParseIfConfig.cpp

@@ -378,7 +378,7 @@ class ValidateIfConfigCondition :
       return E;
     }
 
-    // ( 'os' | 'arch' | '_endian' | '_runtime' ) '(' identifier ')''
+    // ( 'os' | 'arch' | '_endian' | '_pointerBitWidth' | '_runtime' ) '(' identifier ')''
     auto Kind = getPlatformConditionKind(*KindName);
     if (!Kind.has_value()) {
       D.diagnose(E->getLoc(), diag::unsupported_platform_condition_expression);
@@ -412,6 +412,8 @@ class ValidateIfConfigCondition :
         DiagName = "architecture"; break;
       case PlatformConditionKind::Endianness:
         DiagName = "endianness"; break;
+      case PlatformConditionKind::PointerBitWidth:
+        DiagName = "pointer bit width"; break;
       case PlatformConditionKind::CanImport:
         DiagName = "import conditional"; break;
       case PlatformConditionKind::TargetEnvironment:

test/Parse/ConditionalCompilation/aarch64AndroidTarget.swift

@@ -7,7 +7,7 @@
 let i: Int = "Hello"
 #endif
 
-#if arch(arm64) && os(Android) && _runtime(_Native) && _endian(little)
+#if arch(arm64) && os(Android) && _runtime(_Native) && _endian(little) && _pointerBitWidth(_64)
 class C {}
 var x = C()
 #endif

test/Parse/ConditionalCompilation/arm64AppleTVOSTarget.swift

@@ -7,7 +7,7 @@
 let i: Int = "Hello"
 #endif
 
-#if arch(arm64) && os(tvOS) && _runtime(_ObjC) && _endian(little)
+#if arch(arm64) && os(tvOS) && _runtime(_ObjC) && _endian(little) && _pointerBitWidth(_64)
 class C {}
 var x = C()
 #endif

test/Parse/ConditionalCompilation/arm64IOSTarget.swift

@@ -7,7 +7,7 @@
 let i: Int = "Hello"
 #endif
 
-#if arch(arm64) && os(iOS) && _runtime(_ObjC) && _endian(little)
+#if arch(arm64) && os(iOS) && _runtime(_ObjC) && _endian(little) && _pointerBitWidth(_64)
 class C {}
 var x = C()
 #endif

test/Parse/ConditionalCompilation/armAndroidTarget.swift

@@ -7,7 +7,7 @@
 let i: Int = "Hello"
 #endif
 
-#if arch(arm) && os(Android) && _runtime(_Native) && _endian(little)
+#if arch(arm) && os(Android) && _runtime(_Native) && _endian(little) && _pointerBitWidth(_32)
 class C {}
 var x = C()
 #endif

test/Parse/ConditionalCompilation/armIOSTarget.swift

@@ -7,7 +7,7 @@
 let i: Int = "Hello"
 #endif
 
-#if arch(arm) && os(iOS) && _runtime(_ObjC) && _endian(little)
+#if arch(arm) && os(iOS) && _runtime(_ObjC) && _endian(little) && _pointerBitWidth(_32)
 class C {}
 var x = C()
 #endif

test/Parse/ConditionalCompilation/armWatchOSTarget.swift

@@ -7,7 +7,7 @@
 let i: Int = "Hello"
 #endif
 
-#if arch(arm) && os(watchOS) && _runtime(_ObjC) && _endian(little)
+#if arch(arm) && os(watchOS) && _runtime(_ObjC) && _endian(little) && _pointerBitWidth(_32)
 class C {}
 var x = C()
 #endif

test/Parse/ConditionalCompilation/i386AppleTVOSTarget.swift

@@ -7,7 +7,7 @@
 let i: Int = "Hello"
 #endif
 
-#if arch(i386) && os(tvOS) && _runtime(_ObjC) && _endian(little)
+#if arch(i386) && os(tvOS) && _runtime(_ObjC) && _endian(little) && _pointerBitWidth(_32)
 class C {}
 var x = C()
 #endif