nifc: add alignof & offsetof, make sizeof only take type

doc/nifc-spec.md

@@ -96,7 +96,9 @@ Expr ::= Number | CharLiteral | StringLiteral |
          (or Expr Expr) | # "||"
          (not Expr) | # "!"
          (neg Type Expr) |
-         (sizeof Expr) |
+         (sizeof Type) |
+         (alignof Type) |
+         (offsetof Type SYMBOL) |
          (oconstr Type (kv Symbol Expr)*) |  # (object constructor){...}
          (aconstr Type Expr*) |              # array constructor
          (add Type Expr Expr) |

src/nifc/amd64/genasm_e.nim

@@ -785,10 +785,23 @@ proc genx(c: var GeneratedCode; t: Tree; n: NodePos; dest: var Location) =
     genAddr c, t, n.firstSon, dest
   of SizeofC:
     # we evaluate it at compile-time:
-    let a = getAsmSlot(c, n.firstSon)
+    let a = typeToSlot(c, n.firstSon)
     let typ = AsmSlot(kind: AUInt, size: WordSize, align: WordSize)
     let d = immediateLoc(uint(a.size), typ)
     into c, dest, d
+  of AlignofC:
+    # we evaluate it at compile-time:
+    let a = typeToSlot(c, n.firstSon)
+    let typ = AsmSlot(kind: AUInt, size: WordSize, align: WordSize)
+    let d = immediateLoc(uint(a.align), typ)
+    into c, dest, d
+  of OffsetofC:
+    let (obj, fld) = sons2(t, n)
+    let field = t[fld].litId
+    let ftyp = c.fields[field]
+    let typ = AsmSlot(kind: AUInt, size: WordSize, align: WordSize)
+    let d = immediateLoc(uint(ftyp.offset), typ)
+    into c, dest, d
   of CallC: genCall c, t, n, dest
   of AddC: typedBinOp AddT
   of SubC: typedBinOp SubT

src/nifc/amd64/genasm_s.nim

@@ -319,8 +319,16 @@ proc genConstData(c: var GeneratedCode; t: Tree; n: NodePos) =
     let arg = n.firstSon
     genConstData c, t, arg
   of SizeofC:
-    let a = getAsmSlot(c, n.firstSon)
+    let a = typeToSlot(c, n.firstSon)
     c.genIntLit a.size, info
+  of AlignofC:
+    let a = typeToSlot(c, n.firstSon)
+    c.genIntLit a.align, info
+  of OffsetofC:
+    let (obj, fld) = sons2(t, n)
+    let field = t[fld].litId
+    let ftyp = c.fields[field]
+    c.genIntLit ftyp.offset, info
   else:
     error c.m, "unsupported expression for const: ", t, n
 

src/nifc/amd64/register_allocator.nim

@@ -59,7 +59,7 @@ proc allocRegsForProc(c: var GeneratedCode; t: Tree; n: NodePos; weights: Table[
   let k = t[n].kind
   case k
   of Empty, Ident, SymDef, Sym, IntLit, UIntLit, FloatLit, CharLit, StrLit, Err,
-     NilC, FalseC, TrueC, SizeofC, InfC, NegInfC, NanC:
+     NilC, FalseC, TrueC, SizeofC, AlignofC, OffsetofC, InfC, NegInfC, NanC:
     discard
   of StmtsC, ScopeC:
     c.openScope()

src/nifc/cprelude.nim

@@ -260,5 +260,15 @@ typedef NU8 NU;
 
 #define N_NOINLINE_PTR(rettype, name) rettype (*name)
 
+#if defined(_MSC_VER)
+#  define NIM_ALIGN(x)  __declspec(align(x))
+#  define NIM_ALIGNOF(x) __alignof(x)
+#else
+#  define NIM_ALIGN(x)  __attribute__((aligned(x)))
+#  define NIM_ALIGNOF(x) __alignof__(x)
+#endif
+
+#include <stddef.h>
+
 """
 

src/nifc/genexprs.nim

@@ -207,7 +207,23 @@ proc genx(c: var GeneratedCode; t: Tree; n: NodePos) =
     let arg = n.firstSon
     c.add "sizeof"
     c.add ParLe
-    genx c, t, arg
+    genType c, t, arg
+    c.add ParRi
+  of AlignofC:
+    let arg = n.firstSon
+    c.add "NIM_ALIGNOF"
+    c.add ParLe
+    genType c, t, arg
+    c.add ParRi
+  of OffsetofC:
+    let (typ, mem) = sons2(t, n)
+    c.add "offsetof"
+    c.add ParLe
+    genType c, t, typ
+    c.add Comma
+    let lit = t[mem].litId
+    let name = mangle(c.m.lits.strings[lit])
+    c.add name
     c.add ParRi
   of CallC: genCall c, t, n
   of AddC: typedBinOp " + "

src/nifc/native/analyser.nim

@@ -63,7 +63,7 @@ proc analyseVarUsages(c: var Context; t: Tree; n: NodePos) =
   let k = t[n].kind
   case k
   of Empty, Ident, SymDef, IntLit, UIntLit, FloatLit, CharLit, StrLit, Err,
-     NilC, FalseC, TrueC, SizeofC, InfC, NegInfC, NanC:
+     NilC, FalseC, TrueC, SizeofC, AlignofC, OffsetofC, InfC, NegInfC, NanC:
     discard
   of StmtsC, ScopeC:
     c.openScope()

src/nifc/nifc_grammar.nif

@@ -19,7 +19,9 @@
          (or Expr Expr)
          (not Expr)
          (neg Type Expr)
-         (sizeof Expr)
+         (sizeof Type)
+         (alignof Type)
+         (offsetof Type SYMBOL)
          (oconstr Type (ZERO_OR_MANY (kv SYMBOL Expr)))
          (aconstr Type (ZERO_OR_MANY Expr))
          (add Type Expr Expr)

src/nifc/nifc_model.nim

@@ -29,6 +29,8 @@ type
     NotC = "not"
     NegC = "neg"
     SizeofC = "sizeof"
+    AlignofC = "alignof"
+    OffsetofC = "offsetof"
     OconstrC = "oconstr"
     AconstrC = "aconstr"
     KvC = "kv"

src/nifc/preasm/genpreasm_e.nim

@@ -267,8 +267,17 @@ proc genx(c: var GeneratedCode; t: Tree; n: NodePos; mode: XMode) =
     genx c, t, n.firstSon, WantAddr
   of SizeofC:
     # we evaluate it at compile-time:
-    let a = getAsmSlot(c, n.firstSon)
+    let a = typeToSlot(c, n.firstSon)
     genIntLit c, a.size, info
+  of AlignofC:
+    # we evaluate it at compile-time:
+    let a = typeToSlot(c, n.firstSon)
+    genIntLit c, a.align, info
+  of OffsetofC:
+    let (obj, fld) = sons2(t, n)
+    let field = t[fld].litId
+    let ftyp = c.fields[field]
+    genIntLit c, ftyp.offset, info
   of CallC: genCall c, t, n
   of AddC: typedBinOp AddT
   of SubC: typedBinOp SubT

src/nifc/typenav.nim

@@ -96,7 +96,7 @@ proc getType*(m: var Module; t: Tree; n: NodePos): TypeDesc =
   of FldC:
     let v = asFieldDecl(t, n)
     result = TypeDesc(p: v.typ)
-  of IntLit, SizeofC: result = createIntegralType(m.lits, IntC, "-1")
+  of IntLit, SizeofC, AlignofC, OffsetofC: result = createIntegralType(m.lits, IntC, "-1")
   of UIntLit: result = createIntegralType(m.lits, UIntC, "-1")
   of FloatLit, InfC, NegInfC, NanC: result = createIntegralType(m.lits, FloatC, "64")
   of CharLit: result = createIntegralType(m.lits, CharC, "8")