// Compare ABI codegen: normal vs NamedOnly sentinel
// Compile with: ldc2 -O2 -release -output-s abi_comparison.d
//
// Finding: free-function sentinel is zero-overhead (identical asm).
// Struct-field sentinel adds sizeof/alignment overhead (1 byte + padding).

private struct 
(struct) abi_comparison.NamedOnlyNamedOnly {}

struct 
(struct) abi_comparison.RectRect
{
    int 
(field) int abi_comparison.Rect.xx, 
(field) int abi_comparison.Rect.yy, 
(field) int abi_comparison.Rect.widthwidth, 
(field) int abi_comparison.Rect.heightheight;
}

// NamedOnly is 1 byte => 4 bytes with alignment padding before the first int.
// RectNamed.sizeof == 20, Rect.sizeof == 16.
struct 
(struct) abi_comparison.RectNamedRectNamed
{
    
(struct) abi_comparison.NamedOnlyNamedOnly 
(field) abi_comparison.NamedOnly abi_comparison.RectNamed.__ = 
(struct) abi_comparison.NamedOnlyNamedOnly.
(constant) abi_comparison.NamedOnly abi_comparison.NamedOnly.init = NamedOnly()init;
    int 
(field) int abi_comparison.RectNamed.xx, 
(field) int abi_comparison.RectNamed.yy, 
(field) int abi_comparison.RectNamed.widthwidth, 
(field) int abi_comparison.RectNamed.heightheight;
}

pragma(msg, "NamedOnly.sizeof = ", NamedOnly.sizeof);
pragma(msg, "Rect.sizeof      = ", Rect.sizeof);
pragma(msg, "RectNamed.sizeof = ", RectNamed.sizeof);

// --- Free functions: zero overhead ---

export 
(struct) abi_comparison.RectRect 
abi_comparison.Rect abi_comparison.withSentinel(abi_comparison.NamedOnly _ = NamedOnly(), int x = 0, int y = 0, int width = 0, int height = 0, int margin = 0)withSentinel(
    
(struct) abi_comparison.NamedOnlyNamedOnly 
(parameter) abi_comparison.NamedOnly __ = 
(struct) abi_comparison.NamedOnlyNamedOnly.
(constant) abi_comparison.NamedOnly abi_comparison.NamedOnly.init = NamedOnly()init,
    int 
(parameter) int xx = 0, int 
(parameter) int yy = 0, int 
(parameter) int widthwidth = 0, int 
(parameter) int heightheight = 0, int 
(parameter) int marginmargin = 0,
)
{
    return 
(struct) abi_comparison.RectRect(
(parameter) int xx - 
(parameter) int marginmargin, 
(parameter) int yy - 
(parameter) int marginmargin, 
(parameter) int widthwidth + 2 * 
(parameter) int marginmargin, 
(parameter) int heightheight + 2 * 
(parameter) int marginmargin);
}

export 
(struct) abi_comparison.RectRect 
abi_comparison.Rect abi_comparison.withoutSentinel(int x, int y, int width, int height, int margin)withoutSentinel(int 
(parameter) int xx, int 
(parameter) int yy, int 
(parameter) int widthwidth, int 
(parameter) int heightheight, int 
(parameter) int marginmargin)
{
    return 
(struct) abi_comparison.RectRect(
(parameter) int xx - 
(parameter) int marginmargin, 
(parameter) int yy - 
(parameter) int marginmargin, 
(parameter) int widthwidth + 2 * 
(parameter) int marginmargin, 
(parameter) int heightheight + 2 * 
(parameter) int marginmargin);
}

// --- Call sites ---

export 
(struct) abi_comparison.RectRect 
abi_comparison.Rect abi_comparison.callSentinel(int x, int y, int w, int h, int m)callSentinel(int 
(parameter) int xx, int 
(parameter) int yy, int 
(parameter) int ww, int 
(parameter) int hh, int 
(parameter) int mm)
{
    return 
abi_comparison.Rect abi_comparison.withSentinel(abi_comparison.NamedOnly _ = NamedOnly(), int x = 0, int y = 0, int width = 0, int height = 0, int margin = 0)withSentinel(x: 
(parameter) int xx, y: 
(parameter) int yy, width: 
(parameter) int ww, height: 
(parameter) int hh, margin: 
(parameter) int mm);
}

export 
(struct) abi_comparison.RectRect 
abi_comparison.Rect abi_comparison.callPlain(int x, int y, int w, int h, int m)callPlain(int 
(parameter) int xx, int 
(parameter) int yy, int 
(parameter) int ww, int 
(parameter) int hh, int 
(parameter) int mm)
{
    return 
abi_comparison.Rect abi_comparison.withoutSentinel(int x, int y, int width, int height, int margin)withoutSentinel(
(parameter) int xx, 
(parameter) int yy, 
(parameter) int ww, 
(parameter) int hh, 
(parameter) int mm);
}