sizeof alignof offsetof macros api (#10855)

compiler/ast.nim

@@ -662,7 +662,7 @@ type
 
     mNIntVal, mNFloatVal, mNSymbol, mNIdent, mNGetType, mNStrVal, mNSetIntVal,
     mNSetFloatVal, mNSetSymbol, mNSetIdent, mNSetType, mNSetStrVal, mNLineInfo,
-    mNNewNimNode, mNCopyNimNode, mNCopyNimTree, mStrToIdent, mNSigHash,
+    mNNewNimNode, mNCopyNimNode, mNCopyNimTree, mStrToIdent, mNSigHash, mNSizeOf,
     mNBindSym, mLocals, mNCallSite,
     mEqIdent, mEqNimrodNode, mSameNodeType, mGetImpl, mNGenSym,
     mNHint, mNWarning, mNError,

compiler/condsyms.nim

@@ -86,6 +86,7 @@ proc initDefines*(symbols: StringTableRef) =
   defineSymbol("nimHasNilSeqs")
   defineSymbol("nimHasSignatureHashInMacro")
   defineSymbol("nimHasDefault")
+  defineSymbol("nimMacrosSizealignof")
   for f in low(Feature)..high(Feature):
     defineSymbol("nimHas" & $f)
 

compiler/vm.nim

@@ -1477,6 +1477,27 @@ proc rawExecute(c: PCtx, start: int, tos: PStackFrame): TFullReg =
           regs[ra].node = opMapTypeImplToAst(c.cache, regs[rb].node.sym.typ, c.debug[pc])
         else:
           stackTrace(c, tos, pc, "node has no type")
+    of opcNGetSize:
+      decodeBImm(rkInt)
+      let n = regs[rb].node
+      case imm
+      of 0: # size
+        if n.typ == nil:
+          stackTrace(c, tos, pc, "node has no type")
+        else:
+          regs[ra].intVal = getSize(c.config, n.typ)
+      of 1: # align
+        if n.typ == nil:
+          stackTrace(c, tos, pc, "node has no type")
+        else:
+          regs[ra].intVal = getAlign(c.config, n.typ)
+      else: # offset
+        if n.kind != nkSym:
+          stackTrace(c, tos, pc, "node is not a symbol")
+        elif n.sym.kind != skField:
+          stackTrace(c, tos, pc, "symbol is not a field (nskField)")
+        else:
+          regs[ra].intVal = n.sym.offset
     of opcNStrVal:
       decodeB(rkNode)
       createStr regs[ra]

compiler/vmdef.nim

@@ -93,6 +93,7 @@ type
     opcNGetType,
     opcNStrVal,
     opcNSigHash,
+    opcNGetSize,
 
     opcNSetIntVal,
     opcNSetFloatVal, opcNSetSymbol, opcNSetIdent, opcNSetType, opcNSetStrVal,

compiler/vmgen.nim

@@ -1236,6 +1236,12 @@ proc genMagic(c: PCtx; n: PNode; dest: var TDest; m: TMagic) =
     c.gABC(n, opcNGetType, dest, tmp, rc)
     c.freeTemp(tmp)
     #genUnaryABC(c, n, dest, opcNGetType)
+  of mNSizeOf:
+    let imm = case n[0].sym.name.s:
+      of "getSize": 0
+      of "getAlign": 1
+      else: 2 # "getOffset"
+    c.genUnaryABI(n, dest, opcNGetSize, imm)
   of mNStrVal: genUnaryABC(c, n, dest, opcNStrVal)
   of mNSigHash: genUnaryABC(c, n , dest, opcNSigHash)
   of mNSetIntVal: