[clang][AVR] Fix basic type size/alignment values to match avr-gcc.

Closes #102172.

Author: alexrp

clang/include/clang/Basic/TargetInfo.h

@@ -87,6 +87,7 @@ enum class FloatModeKind {
 struct TransferrableTargetInfo {
   unsigned char PointerWidth, PointerAlign;
   unsigned char BoolWidth, BoolAlign;
+  unsigned char ShortWidth, ShortAlign;
   unsigned char IntWidth, IntAlign;
   unsigned char HalfWidth, HalfAlign;
   unsigned char BFloat16Width, BFloat16Align;
@@ -497,13 +498,10 @@ class TargetInfo : public TransferrableTargetInfo,
   unsigned getCharWidth() const { return 8; } // FIXME
   unsigned getCharAlign() const { return 8; } // FIXME
 
-  /// Return the size of 'signed short' and 'unsigned short' for this
-  /// target, in bits.
-  unsigned getShortWidth() const { return 16; } // FIXME
-
-  /// Return the alignment of 'signed short' and 'unsigned short' for
-  /// this target.
-  unsigned getShortAlign() const { return 16; } // FIXME
+  /// getShortWidth/Align - Return the size of 'signed short' and
+  /// 'unsigned short' for this target, in bits.
+  unsigned getShortWidth() const { return ShortWidth; }
+  unsigned getShortAlign() const { return ShortAlign; }
 
   /// getIntWidth/Align - Return the size of 'signed int' and 'unsigned int' for
   /// this target, in bits.

clang/lib/Basic/TargetInfo.cpp

@@ -70,6 +70,7 @@ TargetInfo::TargetInfo(const llvm::Triple &T) : Triple(T) {
   HasStrictFP = false;
   PointerWidth = PointerAlign = 32;
   BoolWidth = BoolAlign = 8;
+  ShortWidth = ShortAlign = 16;
   IntWidth = IntAlign = 32;
   LongWidth = LongAlign = 32;
   LongLongWidth = LongLongAlign = 64;
@@ -437,6 +438,7 @@ void TargetInfo::adjust(DiagnosticsEngine &Diags, LangOptions &Opts) {
     // what these normally are for the target.
     // We also define long long and long double here, although the
     // OpenCL standard only mentions these as "reserved".
+    ShortWidth = ShortAlign = 16;
     IntWidth = IntAlign = 32;
     LongWidth = LongAlign = 64;
     LongLongWidth = LongLongAlign = 128;

clang/lib/Basic/Targets/AVR.h

@@ -29,6 +29,8 @@ class LLVM_LIBRARY_VISIBILITY AVRTargetInfo : public TargetInfo {
     TLSSupported = false;
     PointerWidth = 16;
     PointerAlign = 8;
+    ShortWidth = 16;
+    ShortAlign = 8;
     IntWidth = 16;
     IntAlign = 8;
     LongWidth = 32;
@@ -65,6 +67,8 @@ class LLVM_LIBRARY_VISIBILITY AVRTargetInfo : public TargetInfo {
     return std::nullopt;
   }
 
+  bool allowsLargerPreferedTypeAlignment() const override { return false; }
+
   BuiltinVaListKind getBuiltinVaListKind() const override {
     return TargetInfo::VoidPtrBuiltinVaList;
   }

clang/test/Sema/avr-size-align.c

@@ -0,0 +1,49 @@
+// RUN: %clang_cc1 %s -triple avr -fsyntax-only
+
+_Static_assert(sizeof(char) == 1, "sizeof(char) == 1");
+_Static_assert(_Alignof(char) == 1, "_Alignof(char) == 1");
+_Static_assert(__alignof(char) == 1, "__alignof(char) == 1");
+
+_Static_assert(sizeof(short) == 2, "sizeof(short) == 2");
+_Static_assert(_Alignof(short) == 1, "_Alignof(short) == 1");
+_Static_assert(__alignof(short) == 1, "__alignof(short) == 1");
+
+_Static_assert(sizeof(unsigned short) == 2, "sizeof(unsigned short) == 2");
+_Static_assert(_Alignof(unsigned short) == 1, "_Alignof(unsigned short) == 1");
+_Static_assert(__alignof(unsigned short) == 1, "__alignof(unsigned short) == 1");
+
+_Static_assert(sizeof(int) == 2, "sizeof(int) == 2");
+_Static_assert(_Alignof(int) == 1, "_Alignof(int) == 1");
+_Static_assert(__alignof(int) == 1, "__alignof(int) == 1");
+
+_Static_assert(sizeof(unsigned int) == 2, "sizeof(unsigned int) == 2");
+_Static_assert(_Alignof(unsigned int) == 1, "_Alignof(unsigned int) == 1");
+_Static_assert(__alignof(unsigned int) == 1, "__alignof(unsigned int) == 1");
+
+_Static_assert(sizeof(long) == 4, "sizeof(long) == 4");
+_Static_assert(_Alignof(long) == 1, "_Alignof(long) == 1");
+_Static_assert(__alignof(long) == 1, "__alignof(long) == 1");
+
+_Static_assert(sizeof(unsigned long) == 4, "sizeof(unsigned long) == 4");
+_Static_assert(_Alignof(unsigned long) == 1, "_Alignof(unsigned long) == 1");
+_Static_assert(__alignof(unsigned long) == 1, "__alignof(unsigned long) == 1");
+
+_Static_assert(sizeof(long long) == 8, "sizeof(long long) == 8");
+_Static_assert(_Alignof(long long) == 1, "_Alignof(long long) == 1");
+_Static_assert(__alignof(long long) == 1, "__alignof(long long) == 1");
+
+_Static_assert(sizeof(unsigned long long) == 8, "sizeof(unsigned long long) == 8");
+_Static_assert(_Alignof(unsigned long long) == 1, "_Alignof(unsigned long long) == 1");
+_Static_assert(__alignof(unsigned long long) == 1, "__alignof(unsigned long long) == 1");
+
+_Static_assert(sizeof(float) == 4, "sizeof(float) == 4");
+_Static_assert(_Alignof(float) == 1, "_Alignof(float) == 1");
+_Static_assert(__alignof(float) == 1, "__alignof(float) == 1");
+
+_Static_assert(sizeof(double) == 4, "sizeof(double) == 4");
+_Static_assert(_Alignof(double) == 1, "_Alignof(double) == 1");
+_Static_assert(__alignof(double) == 1, "__alignof(double) == 1");
+
+_Static_assert(sizeof(long double) == 4, "sizeof(long double) == 4");
+_Static_assert(_Alignof(long double) == 1, "_Alignof(long double) == 1");
+_Static_assert(__alignof(long double) == 1, "__alignof(long double) == 1");