handle cases i can find of array to pointer decay

compiler/cbuilderexprs.nim

@@ -465,3 +465,9 @@ template cUnlikely(val: Snippet): Snippet =
     val # not implemented
   else:
     "NIM_UNLIKELY(" & val & ")"
+
+template arrayAddr(val: Snippet): Snippet =
+  when buildNifc:
+    cAddr(subscript(val, cIntValue(0)))
+  else:
+    val

compiler/ccgcalls.nim

@@ -407,6 +407,8 @@ proc genArg(p: BProc, n: PNode, param: PSym; call: PNode; result: var Builder; n
         {lfHeader, lfNoDecl} * callee.sym.loc.flags != {} and
         needsIndirect:
       addAddrLoc(p.config, a, result)
+    elif not needsIndirect and buildNifc:
+      addAddrLoc(p.config, a, result)
     else:
       addRdLoc(a, result)
   else:

compiler/ccgexprs.nim

@@ -463,8 +463,8 @@ proc genAssignment(p: BProc, dest, src: TLoc, flags: TAssignmentFlags) =
       let rd = rdLoc(dest)
       let rs = rdLoc(src)
       p.s(cpsStmts).addCallStmt(cgsymValue(p.module, "nimCopyMem"),
-        cCast(CPointer, rd),
-        cCast(CConstPointer, rs),
+        cCast(CPointer, arrayAddr(rd)),
+        cCast(CConstPointer, arrayAddr(rs)),
         cIntValue(getSize(p.config, dest.t)))
     else:
       simpleAsgn(p.s(cpsStmts), dest, src)
@@ -530,8 +530,8 @@ proc genDeepCopy(p: BProc; dest, src: TLoc) =
       let rd = rdLoc(dest)
       let rs = rdLoc(src)
       p.s(cpsStmts).addCallStmt(cgsymValue(p.module, "nimCopyMem"),
-        cCast(CPointer, rd),
-        cCast(CConstPointer, rs),
+        cCast(CPointer, arrayAddr(rd)),
+        cCast(CConstPointer, arrayAddr(rs)),
         cIntValue(getSize(p.config, dest.t)))
     else:
       simpleAsgn(p.s(cpsStmts), dest, src)
@@ -1006,7 +1006,8 @@ proc genAddr(p: BProc, e: PNode, d: var TLoc) =
     var a: TLoc = initLocExpr(p, e[0])
     putIntoDest(p, d, e, cAddr(a.snippet), a.storage)
     #Message(e.info, warnUser, "HERE NEW &")
-  elif mapType(p.config, e[0].typ, mapTypeChooser(e[0]) == skParam) == ctArray or isCppRef(p, e.typ):
+  elif (mapType(p.config, e[0].typ, mapTypeChooser(e[0]) == skParam) == ctArray and
+      not buildNifc) or isCppRef(p, e.typ):
     expr(p, e[0], d)
     # bug #19497
     d.lode = e
@@ -1462,7 +1463,7 @@ proc genEcho(p: BProc, n: PNode) =
       var a: TLoc = initLocExpr(p, n)
       let ra = a.rdLoc
       p.s(cpsStmts).addCallStmt(cgsymValue(p.module, "echoBinSafe"),
-        ra,
+        arrayAddr(ra),
         cIntValue(n.len))
     when false:
       p.module.includeHeader("<stdio.h>")

compiler/ccgtypes.nim

@@ -1818,7 +1818,7 @@ proc genTypeInfoV2OldImpl(m: BModule; t, origType: PType, name: Rope; info: TLin
       else:
         let arrTyp = ""
       genDisplay(m.s[cfsVars], m, t, objDepth, arrTyp)
-    typeEntry.addFieldAssignment(name, "display", objDisplayStore)
+    typeEntry.addFieldAssignment(name, "display", arrayAddr(objDisplayStore))
 
   let dispatchMethods = toSeq(getMethodsPerType(m.g.graph, t))
   if dispatchMethods.len > 0:
@@ -1883,7 +1883,7 @@ proc genTypeInfoV2Impl(m: BModule; t, origType: PType, name: Rope; info: TLineIn
               len = objDepth + 1):
             genDisplay(m.s[cfsVars], m, t, objDepth)
           typeEntry.addField(typeInit, name = "display"):
-            typeEntry.add(objDisplayStore)
+            typeEntry.add(arrayAddr(objDisplayStore))
         if isDefined(m.config, "nimTypeNames"):
           var typeName: Rope
           if t.kind in {tyObject, tyDistinct}:

compiler/cgen.nim

@@ -409,23 +409,28 @@ template mapTypeChooser(n: PNode): TSymKind =
 template mapTypeChooser(a: TLoc): TSymKind = mapTypeChooser(a.lode)
 
 proc addAddrLoc(conf: ConfigRef; a: TLoc; result: var Builder) =
-  if lfIndirect notin a.flags and mapType(conf, a.t, mapTypeChooser(a) == skParam) != ctArray:
-    result.add wrapPar(cAddr(a.snippet))
-  else:
+  if lfIndirect in a.flags:
     result.add a.snippet
+  elif mapType(conf, a.t, mapTypeChooser(a) == skParam) == ctArray:
+    result.add arrayAddr(a.snippet)
+  else:
+    result.add wrapPar(cAddr(a.snippet))
 
 proc addrLoc(conf: ConfigRef; a: TLoc): Rope =
-  if lfIndirect notin a.flags and mapType(conf, a.t, mapTypeChooser(a) == skParam) != ctArray:
-    result = wrapPar(cAddr(a.snippet))
-  else:
+  if lfIndirect in a.flags:
     result = a.snippet
+  elif mapType(conf, a.t, mapTypeChooser(a) == skParam) == ctArray:
+    result = arrayAddr(a.snippet)
+  else:
+    result = wrapPar(cAddr(a.snippet))
 
 proc byRefLoc(p: BProc; a: TLoc): Rope =
-  if lfIndirect notin a.flags and mapType(p.config, a.t, mapTypeChooser(a) == skParam) != ctArray and not
-      p.module.compileToCpp:
-    result = wrapPar(cAddr(a.snippet))
-  else:
+  if lfIndirect in a.flags or p.module.compileToCpp:
     result = a.snippet
+  elif mapType(p.config, a.t, mapTypeChooser(a) == skParam) == ctArray:
+    result = arrayAddr(a.snippet)
+  else:
+    result = wrapPar(cAddr(a.snippet))
 
 proc rdCharLoc(a: TLoc): Rope =
   # read a location that may need a char-cast: