diff --git a/analyser/conversion_checker.c2 b/analyser/conversion_checker.c2
index 95237d23c..00972bac2 100644
--- a/analyser/conversion_checker.c2
+++ b/analyser/conversion_checker.c2
@@ -118,7 +118,7 @@ public type Checker struct {
 public fn void Checker.init(Checker* c, diagnostics.Diags* diags, ast_builder.Builder* builder) {
     c.diags = diags;
     c.builder = builder;
-    c.native_kind = ast.getNativeKind();
+    c.native_kind = builder.getNativeKind();
     // leave other fields uninitialized
 }
 
diff --git a/analyser/conversion_checker_expr.c2 b/analyser/conversion_checker_expr.c2
index 9fb04f7d6..7b9d9725d 100644
--- a/analyser/conversion_checker_expr.c2
+++ b/analyser/conversion_checker_expr.c2
@@ -128,9 +128,6 @@ fn ExprWidth getUnaryOpWidth(const UnaryOperator* u) {
         // TODO adjust for integer promotion?
         return getExprWidth(u.getInner());
     case AddrOf:
-        w.width = (u8)(ast.getWordSize() * 8);
-        w.is_signed = false;
-        break;
     case Deref:
         Expr* e = (Expr*)u;
         return getTypeWidth(e.getType());
@@ -228,7 +225,7 @@ fn ExprWidth getTypeWidth(QualType qt) {
         return result;
     }
     // pointer or something
-    ExprWidth result = { .width = (u8)(ast.getWordSize() * 8), .is_signed = false }
+    ExprWidth result = { .width = (u8)(qt.getAlignment() * 8), .is_signed = false }
     return result;
 }
 
diff --git a/analyser/size_analyser.c2 b/analyser/size_analyser.c2
index 4b490980c..c1eec6fa9 100644
--- a/analyser/size_analyser.c2
+++ b/analyser/size_analyser.c2
@@ -185,21 +185,20 @@ public fn TypeSize sizeOfType(QualType qt) {
 
     if (qt.isInvalid()) return result;
 
-    u32 pointerSize = getWordSize();
-
     qt = qt.getCanonicalType();
     Type* t = qt.getType();
     switch (t.getKind()) {
     case Builtin:
         const BuiltinType* bi = (BuiltinType*)t;
         // NOTE: alignment is also size
-        result.size = bi.getAlignment();
-        result.align = result.size;
+        result.align = bi.getAlignment();
+        result.size = result.align;
         result.is_signed = bi.isSigned();
         break;
     case Pointer:
-        result.size = pointerSize;
-        result.align = result.size;
+    case Function:
+        result.align = t.getAlignment();
+        result.size = result.align;
         break;
     case Array:
         ArrayType* arrayType = (ArrayType*)t;
@@ -218,10 +217,6 @@ public fn TypeSize sizeOfType(QualType qt) {
         EnumType* et = (EnumType*)t;
         EnumTypeDecl* etd = et.getDecl();
         return sizeOfType(etd.getImplType());
-    case Function:
-        result.size = pointerSize;
-        result.align = pointerSize;
-        break;
     case Void:
         result.size = 0;
         result.align = 0;
diff --git a/ast/builtin_type.c2 b/ast/builtin_type.c2
index 440405f80..dea5a9572 100644
--- a/ast/builtin_type.c2
+++ b/ast/builtin_type.c2
@@ -24,10 +24,10 @@ public type BuiltinKind enum u8 (public const char* const name,
                                  const bool is_signed,
                                  const bool is_unsigned,
                                  const bool is_integer,
-                                 const u8 default_size,
-                                 const u8 default_width)
+                                 const u8 align,
+                                 const u8 width)
 {
-    // Note: default_size/width is adjusted for 32-bit in globals
+    // Note: align/width is adjusted for 32-bit in globals
     Char        : { "char",  true,  false, true,  true,  1,  8 },
     Int8        : { "i8",    true,  true,  false, true,  1,  8 },
     Int16       : { "i16",   true,  true,  false, true,  2, 16 },
@@ -39,17 +39,16 @@ public type BuiltinKind enum u8 (public const char* const name,
     UInt64      : { "u64",   false, false, true,  true,  8, 64 },
     Float32     : { "f32",   false, true,  false, false, 4,  0 },
     Float64     : { "f64",   false, true,  false, false, 8,  0 },
-    ISize       : { "isize", false, true,  false, true,  8, 64 },
-    USize       : { "usize", false, false, true,  true,  8, 64 },
+    ISize       : { "isize", false, true,  false, true,  0,  0 },
+    USize       : { "usize", false, false, true,  true,  0,  0 },
     Bool        : { "bool",  true,  false, false, false, 1,  1 },
 }
 
 type BuiltinTypeBits struct {
-    u32 : NumTypeBits;  // : 8
+    u32 : NumTypeBits;  // : 16
     BuiltinKind kind : 4;
     BuiltinKind base_kind : 4;
     u32 width : 8;
-    u32 size : 8;
 }
 static_assert(sizeof(BuiltinTypeBits), 4);
 
@@ -57,16 +56,16 @@ public type BuiltinType struct @(opaque) {
     Type base;
 }
 
-fn BuiltinType* BuiltinType.create(ast_context.Context* c, BuiltinKind kind, u32 wordsize) {
+fn BuiltinType* BuiltinType.create(ast_context.Context* c, BuiltinKind kind) {
+    BuiltinKind base_kind = kind;
+    if (kind == ISize) base_kind = (c.getWordSize() == 4) ? Int32 : Int64;
+    if (kind == USize) base_kind = (c.getWordSize() == 4) ? UInt32 : UInt64;
     BuiltinType* b = c.alloc(sizeof(BuiltinType));
     b.base.init(Builtin);
-    BuiltinKind base_kind = kind;
-    if (kind == ISize) base_kind = (wordsize == 4) ? Int32 : Int64;
-    if (kind == USize) base_kind = (wordsize == 4) ? UInt32 : UInt64;
     b.base.builtinTypeBits.kind = kind;
     b.base.builtinTypeBits.base_kind = base_kind;
-    b.base.builtinTypeBits.width = base_kind.default_width;
-    b.base.builtinTypeBits.size = base_kind.default_size;
+    b.base.builtinTypeBits.width = base_kind.width;
+    b.base.setAlignment(base_kind.align);
     b.base.setCanonicalType(QualType.create(&b.base));
 #if AstStatistics
     Stats.addType(Builtin, sizeof(BuiltinType));
@@ -120,7 +119,7 @@ public fn bool BuiltinType.isUnsigned(const BuiltinType* b) {
 }
 
 public fn u32 BuiltinType.getAlignment(const BuiltinType* b) {
-    return b.base.builtinTypeBits.size;
+    return b.base.typeBits.align;
 }
 
 public fn u32 BuiltinType.getWidth(const BuiltinType* b) {
diff --git a/ast/function_type.c2 b/ast/function_type.c2
index a044d3140..be2cd28f8 100644
--- a/ast/function_type.c2
+++ b/ast/function_type.c2
@@ -26,6 +26,7 @@ public type FunctionType struct @(opaque) {
 fn FunctionType* FunctionType.create(ast_context.Context* c, FunctionDecl* decl) {
     FunctionType* t = c.alloc(sizeof(FunctionType));
     t.base.init(Function);
+    t.base.setAlignment(c.getWordSize());
     t.decl = decl;
 
     t.base.setCanonicalType(QualType.create(&t.base));
diff --git a/ast/pointer_pool.c2 b/ast/pointer_pool.c2
index d0331386e..f58255db4 100644
--- a/ast/pointer_pool.c2
+++ b/ast/pointer_pool.c2
@@ -42,11 +42,12 @@ type PointerPool struct {
 }
 
 fn void PointerPool.init(PointerPool* p, ast_context.Context* c) {
+    p.context = c;
     p.count = 1;    // skip first slot
     p.capacity = 0;
     p.slots = nil;
-    p.context = c;
     p.resize(64);
+    memset(p.slots, 0, sizeof(p.slots[0]));
 }
 
 fn void PointerPool.clear(PointerPool* p) {
diff --git a/ast/pointer_type.c2 b/ast/pointer_type.c2
index d08343011..601b64c5e 100644
--- a/ast/pointer_type.c2
+++ b/ast/pointer_type.c2
@@ -27,6 +27,7 @@ public type PointerType struct @(opaque) {
 fn PointerType* PointerType.create(ast_context.Context* c, QualType inner) {
     PointerType* t = c.alloc(sizeof(PointerType));
     t.base.init(Pointer);
+    t.base.setAlignment(c.getWordSize());
     t.inner = inner;
 #if AstStatistics
     Stats.addType(Pointer, sizeof(PointerType));
diff --git a/ast/type.c2 b/ast/type.c2
index 064e49fac..da3f3d5b3 100644
--- a/ast/type.c2
+++ b/ast/type.c2
@@ -31,8 +31,9 @@ public type TypeKind enum u8 (const char* const name) {
 
 type TypeBits struct {
     TypeKind kind : 8;
+    u32 align : 8;
 }
-const u32 NumTypeBits = 8;
+const u32 NumTypeBits = 16;
 
 public type Type struct @(opaque) {
     union {
@@ -48,6 +49,7 @@ public type Type struct @(opaque) {
 fn void Type.init(Type* t, TypeKind k) {
     t.bits = 0;
     t.typeBits.kind = k;
+    t.typeBits.align = 0;
     t.ptr_pool_idx = 0;
     t.canonicalType.ptr = 0;
 }
@@ -101,13 +103,16 @@ public fn void Type.dump(const Type* t) @(unused) {
     ast.flushDumpBuf(out);
 }
 
-fn u32 Type.getAlignment(const Type* t) {
+fn void Type.setAlignment(Type* t, u32 align) {
+    t.typeBits.align = align;
+}
+
+public fn u32 Type.getAlignment(const Type* t) {
     switch (t.getKind()) {
     case Builtin:
-        const BuiltinType* bi = (BuiltinType*)t;
-        return bi.getAlignment();
     case Pointer:
-        break;
+    case Function:
+        return t.typeBits.align;
     case Array:
         const ArrayType* at = (ArrayType*)t;
         QualType elem = at.getElemType();
@@ -121,8 +126,6 @@ fn u32 Type.getAlignment(const Type* t) {
         const EnumTypeDecl* etd = e.getDecl();
         QualType it = etd.getImplType();
         return it.getTypeOrNil().getAlignment();
-    case Function:
-        break;
     case Void:
         return 0;
     case Alias:
@@ -132,7 +135,7 @@ fn u32 Type.getAlignment(const Type* t) {
         // should not happen
         return 0;
     }
-    return getWordSize();
+    return 0;
 }
 
 fn u32 Type.getElemSize(const Type* t) {
@@ -159,7 +162,8 @@ fn u32 Type.getSize(const Type* t) {
         const BuiltinType* bi = (BuiltinType*)t;
         return bi.getAlignment();   // note: alignment is size
     case Pointer:
-        break;
+    case Function:
+        return t.getAlignment();
     case Array:
         const ArrayType* at = (ArrayType*)t;
         QualType elem = at.getElemType();
@@ -173,8 +177,6 @@ fn u32 Type.getSize(const Type* t) {
         const EnumTypeDecl* etd = e.getDecl();
         QualType it = etd.getImplType();
         return it.getSize();
-    case Function:
-        break;
     case Void:
         return 0;
     case Alias:
@@ -184,7 +186,7 @@ fn u32 Type.getSize(const Type* t) {
         // should not happen
         return 0;
     }
-    return getWordSize();
+    return 0;
 }
 
 fn void Type.print(const Type* t, string_buffer.Buf* out) {
diff --git a/ast/utils.c2 b/ast/utils.c2
index 22ca850dc..92d488265 100644
--- a/ast/utils.c2
+++ b/ast/utils.c2
@@ -105,7 +105,6 @@ public type Globals struct @(opaque) {
     string_pool.Pool* names_pool;
     PointerPool pointers;
     StringTypePool string_types;
-    u32 wordsize;       // 4 or 8 (in bytes)
     bool use_color;
     // TODO just use AST vector (also in modules, but modules has ownership)
     u32 ast_count;      // Note: first index used to indicate nil
@@ -127,11 +126,10 @@ public fn Globals* getGlobals() { return globals; }
 public fn void setGlobals(Globals* g) @(unused) { globals = g; }
 
 // wordsize in bytes, must NOT be called from Plugin!
-public fn void initialize(Context* c, string_pool.Pool* astPool, u32 wordsize, bool use_color) {
+public fn void initialize(Context* c, string_pool.Pool* astPool, bool use_color) {
     Globals* g = stdlib.calloc(sizeof(Globals), 1);
     g.pointers.init(c);
     g.string_types.init(c);
-    g.wordsize = wordsize;
     g.use_color = use_color;
     g.names_pool = astPool;
     g.ast_count = 1;
@@ -145,7 +143,7 @@ public fn void initialize(Context* c, string_pool.Pool* astPool, u32 wordsize, b
 
     // create all Qualtypes for builtin-types
     for (BuiltinKind kind = BuiltinKind.min; kind <= BuiltinKind.max; kind++) {
-        g.builtins[kind].set((Type*)BuiltinType.create(c, kind, wordsize));
+        g.builtins[kind].set((Type*)BuiltinType.create(c, kind));
     }
 
     // create void type and void-ptr type
@@ -180,10 +178,6 @@ public fn void deinit() {
     globals = nil;
 }
 
-public fn u32 getWordSize() {
-    return globals.wordsize;
-}
-
 public fn bool useColor() @(unused) {
     return globals.use_color;
 }
@@ -257,10 +251,6 @@ fn void flushDumpBuf(string_buffer.Buf* out) {
     out.clear();
 }
 
-public fn BuiltinKind getNativeKind() {
-    return globals.wordsize == 8 ? UInt64 : UInt32;
-}
-
 Color col_Stmt = Color.Bmagenta;
 Color col_Decl = Color.Bgreen;
 Color col_Expr = Color.Bmagenta;
diff --git a/ast_utils/context.c2 b/ast_utils/context.c2
index 7765641c7..8a482c954 100644
--- a/ast_utils/context.c2
+++ b/ast_utils/context.c2
@@ -45,7 +45,7 @@ fn Block* Block.free(Block* b) {
     return next;
 }
 
-public type Context struct @(opaque) {
+type TailAllocator struct {
     Block* blk_head;
     Block* blk_tail;
     u32 blk_size;
@@ -55,7 +55,7 @@ public type Context struct @(opaque) {
     u32 cur_allocated;
 }
 
-fn void Context.init(Context* c, u32 blk_size) {
+fn void TailAllocator.init(TailAllocator* c, u32 blk_size) {
     c.blk_head = nil;
     c.blk_tail = nil;
     c.blk_size = blk_size >= 1024 ? blk_size - sizeof(Block) : blk_size;
@@ -65,31 +65,13 @@ fn void Context.init(Context* c, u32 blk_size) {
     c.cur_allocated = 0;
 }
 
-public fn Context* create(u32 blk_size) {
-    Context* c = malloc(sizeof(Context));
-    c.init(blk_size);
-    return c;
-}
-
-fn void Context.freeBlocks(Context* c) {
+fn void TailAllocator.freeBlocks(TailAllocator* c) {
     Block* blk = c.blk_head;
     while (blk) blk = blk.free();
     c.blk_head = c.blk_tail = nil;
 }
 
-public fn void Context.free(Context* c) {
-    c.freeBlocks();
-    free(c);
-}
-
-/*
-public fn void Context.clear(Context* c) {
-    c.freeBlocks();
-    c.init();
-}
-*/
-
-public fn void* Context.alloc(Context* c, u32 len) {
+fn void* TailAllocator.alloc(TailAllocator* c, u32 len) {
     len = (len + 7) & ~0x7; // always round to 8-byte boundaries
     c.num_allocs++;
 
@@ -116,7 +98,7 @@ public fn void* Context.alloc(Context* c, u32 len) {
 
 #if 0
 // Make sure len bytes fit sequentially, does NOT allocate!
-public fn void Context.reserve(Context* c, u32 len) {
+public fn void TailAllocator.reserve(TailAllocator* c, u32 len) {
     len = (len + 7) & ~0x7; // always round to 8-byte boundaries
     c.alloc(len);
     c.num_allocs--;
@@ -124,7 +106,7 @@ public fn void Context.reserve(Context* c, u32 len) {
 }
 #endif
 
-public fn void Context.report(const Context* c) {
+fn void TailAllocator.report(const TailAllocator* c) {
     u32 blocks = 0;
     u32 total = 0;
     u32 slack = 0;
@@ -141,3 +123,41 @@ public fn void Context.report(const Context* c) {
     stdio.printf("context: %d allocs, total %d (%d KB), avg %d bytes, %d blocks (%d), slack %d, avail %d\n",
         c.num_allocs, total, (total + 1023) / 1024, avg, blocks, c.blk_size, slack, avail);
 }
+
+// TODO: rename this AstContext and move to ast module
+
+public type Context struct @(opaque) {
+    TailAllocator allocator;
+    u32 blk_size;
+    u32 wordsize;
+}
+
+public fn Context* create(u32 blk_size, u32 wordsize) {
+    Context* c = malloc(sizeof(Context));
+    c.allocator.init(blk_size);
+    c.blk_size = blk_size;
+    c.wordsize = wordsize;
+    return c;
+}
+
+public fn void Context.free(Context* c) {
+    c.allocator.freeBlocks();
+    free(c);
+}
+
+#if 0
+public fn void Context.clear(Context* c) {
+    c.allocator.freeBlocks();
+    c.allocator.init(c.blk_size);
+}
+#endif
+
+public fn u32 Context.getWordSize(Context* c) { return c.wordsize; }
+
+public fn void* Context.alloc(Context* c, u32 len) {
+    return c.allocator.alloc(len);
+}
+
+public fn void Context.report(Context* c) {
+    c.allocator.report();
+}
diff --git a/common/ast_builder.c2 b/common/ast_builder.c2
index 5b82a7e72..6cc6dd89d 100644
--- a/common/ast_builder.c2
+++ b/common/ast_builder.c2
@@ -37,10 +37,11 @@ public type Builder struct @(opaque) {
     Module* mod;                // no ownership
     AST* ast;
     u32 ast_idx;
-    u32 c2_name;
-    u32 main_name;
+    u32 c2_name;        // index into astPool
+    u32 main_name;      // index into astPool
     bool is_interface;
     bool is_private;
+    BuiltinKind native_kind;
 
     Attr[8] attrs;
     u32 num_attrs;
@@ -63,6 +64,7 @@ public fn Builder* create(Context* context,
     b.auxPool = auxPool;
     b.c2_name = c2_name;
     b.main_name = main_name;
+    b.native_kind = context.getWordSize() == 8 ? UInt64 : UInt32;
     b.attr_handler = attr_handler_;
 
     return b;
@@ -95,6 +97,10 @@ public fn bool Builder.setExternal(Builder* b, bool is_interface) {
     return was_interface;
 }
 
+public fn BuiltinKind Builder.getNativeKind(Builder* b) {
+    return b.native_kind;
+}
+
 public fn void Builder.actOnModule(Builder* b,
                                    u32 mod_name,
                                    SrcLoc mod_loc,
diff --git a/compiler/compiler.c2 b/compiler/compiler.c2
index 7a90e2154..89fc36887 100644
--- a/compiler/compiler.c2
+++ b/compiler/compiler.c2
@@ -206,7 +206,6 @@ fn void Compiler.build(Compiler* c,
     diags.setWarningAsError(target.getWarnings().are_errors);
     c.diags.clear();
 
-    c.context = ast_context.create(16*1024);
     c.astPool = string_pool.create(128*1024, 4096);
 
     // Note: keywords must be added first
@@ -219,15 +218,6 @@ fn void Compiler.build(Compiler* c,
 
     c.parse_queue.init(false, 64);
 
-    c.attr_handler = attr_handler.create(diags, c.astPool, target.getWarnings());
-    c.builder = ast_builder.create(c.context,
-                                   diags,
-                                   c.astPool,
-                                   c.auxPool,
-                                   c2_idx,
-                                   c.main_idx,
-                                   c.attr_handler);
-
     c.allmodules.init(false, 128);
     c.components.init();
     c.is_image = target.getKind() == Image;
@@ -289,6 +279,21 @@ fn void Compiler.build(Compiler* c,
 #ifndef BOOTSTRAP
     c.addFeature("EXPERIMENTAL", "1");
 #endif
+
+    // TODO: reorganize these objects:
+    //  ast.AstContext should the global object
+    c.context = ast_context.create(16*1024, c.targetInfo.intWidth / 8);
+    ast.initialize(c.context, c.astPool, color.useColor());
+
+    c.attr_handler = attr_handler.create(diags, c.astPool, target.getWarnings());
+    c.builder = ast_builder.create(c.context,
+                                   diags,
+                                   c.astPool,
+                                   c.auxPool,
+                                   c2_idx,
+                                   c.main_idx,
+                                   c.attr_handler);
+
     c.parser = c2_parser.create(sm,
                                 diags,
                                 c.astPool,
@@ -297,8 +302,6 @@ fn void Compiler.build(Compiler* c,
                                 c.target.getFeatures(),
                                 c.target.hasAsserts());
 
-    ast.initialize(c.context, c.astPool, c.targetInfo.intWidth / 8, color.useColor());
-
     c.analyser = module_analyser.create(c.diags,
                                         c.context,
                                         c.astPool,
diff --git a/generator/c/c_generator.c2 b/generator/c/c_generator.c2
index 3e6bf8993..f207d7eac 100644
--- a/generator/c/c_generator.c2
+++ b/generator/c/c_generator.c2
@@ -1456,7 +1456,7 @@ fn void Generator.emit_external_header(Generator* gen, string_buffer.Buf* out) {
     out.add(Include_guard1);
     out.add(Warning_control);
     out.add(C_types);
-    if (ast.getWordSize() == 4) {
+    if (gen.targetInfo.intWidth == 32) {
         // ILP32 (32-bit int, long and pointers)
         out.add(```c
                 typedef signed long long i64;
diff --git a/generator/ir/ir_generator.c2 b/generator/ir/ir_generator.c2
index 992aa7e1b..299c0e3f7 100644
--- a/generator/ir/ir_generator.c2
+++ b/generator/ir/ir_generator.c2
@@ -224,6 +224,7 @@ fn ir.Type Generator.type2irtype(Generator* gen, QualType qt) {
     case Void:
         return None;
     case Pointer:
+    case Function:
         // TODO 32-bits
         return ir.Type.I64;
     case Array:
@@ -247,9 +248,6 @@ fn ir.Type Generator.type2irtype(Generator* gen, QualType qt) {
     case Enum:
         EnumType* et = canon.getEnum();
         return gen.type2irtype(et.getImplType());
-    case Function:
-        // TODO 32-bits
-        return ir.Type.I64;
     case Alias:
         assert(0);
         break;