stride3d/stride · error · InvalidOperationException

SPIRV Magic number not found

Error message

SPIRV Magic number not found

What it means

SpirvBytecode.CreateFromSpan validates that the first 32-bit word of the buffer equals the SPIR-V magic number 0x07230203 before parsing the header. If the data does not start with that magic, the span is not SPIR-V bytecode and parsing would produce garbage, so it throws immediately.

Solutions

1. Verify the input actually is SPIR-V: check the first four bytes are 0x03 0x02 0x23 0x07 before calling CreateFromSpan
2. Ensure you pass the SPIR-V module itself, not a container or source text; strip any wrapping header first
3. Confirm the byte->int cast uses correct endianness (little-endian words) and that no offset shifted the start of the module

Example fix

// before
var bytecode = SpirvBytecode.CreateFromSpan(File.ReadAllBytes("shader.fxc")); // DXBC, not SPIR-V
// after
var bytes = File.ReadAllBytes("shader.spv");
if (bytes.Length >= 4 && bytes[0] == 0x03 && bytes[1] == 0x02 && bytes[2] == 0x23 && bytes[3] == 0x07)
    var bytecode = SpirvBytecode.CreateFromSpan(bytes);

static bool LooksLikeSpirv(ReadOnlySpan<byte> bytes) =>
    bytes.Length >= 4 && bytes[0] == 0x03 && bytes[1] == 0x02 && bytes[2] == 0x23 && bytes[3] == 0x07;

if (!LooksLikeSpirv(bytes))
    throw new InvalidDataException("Input is not SPIR-V (magic number 0x07230203 missing).");

static bool IsSpirvMagic(Span<int> words) => words.Length > 0 && words[0] == 0x07230203;

try
{
    var bytecode = SpirvBytecode.CreateFromSpan(span);
}
catch (InvalidOperationException ex) when (ex.Message == "SPIRV Magic number not found")
{
    log.Error("Input blob is not SPIR-V bytecode (bad magic); check the source container/format.");
}

When it happens

Trigger: Calling CreateFromSpan(byte[]/Span<byte>) or CreateFromSpan(Span<int>) with data that is not SPIR-V: raw HLSL/GLSL text, a D3D bytecode blob (DXBC), a truncated buffer, a byte-order/endian-mangled blob, or an offset into a larger file that skips the header.

Common situations: Passing compiled DXBC instead of SPIR-V; passing shader source text; reading a shader cache file with a container header still attached; a save/load pipeline that trims or re-orders bytes; platform endianness differences when filling the int span.

Understand the failure class

Background: "Invalid ... format", "must be in format X", "does not look like a ..." — invalid argument format errors across CLI tools and libraries — this error's family across 17 libraries.

Related errors

• SPIRV Magic number not found
• 64bit integers
• Binary operator not supported for element type
• BuildInheritanceListWithoutSelf: OpMixinInheritSDSL…
• bytecode

AI-assisted analysis of stride3d/stride@96fad776d2 (2026-09-14). Data as JSON: /api/errors/0e77fcf25aafee60. Report an issue: GitHub.

Appendix: source

Thrown at sources/shaders/Stride.Shaders.Spirv/Buffers/SpirvBytecode.cs:40

                bound = index + 1;
        }
        return new SpirvHeader("1.4", 0, bound);
    }

    public Span<byte> ToSpan()
    {
        return CreateBytecodeFromBuffers(Header, false, Buffer);
    }

    public static SpirvBytecode CreateFromSpan(Span<byte> span)
    {
        return CreateFromSpan(MemoryMarshal.Cast<byte, int>(span));
    }

    public static SpirvBytecode CreateFromSpan(Span<int> span)
    {
        if (span[0] != Specification.MagicNumber)
            throw new InvalidOperationException("SPIRV Magic number not found");

        var header = SpirvHeader.Read(span);

        return new(header, new SpirvBuffer(span[SpirvHeader.IntSpanSize..]));
    }

    // Returns a freshly allocated array. Do not back this with ArrayPool/SpanOwner: the caller
    // receives a Span that carries no ownership, so a pooled buffer would be returned to the pool
    // by the finalizer and reused while the span is still in use, silently corrupting the bytecode
    // (e.g. another shader's OpCapability bleeding into vkCreateShaderModule input).
    public static Span<int> CreateSpanFromBuffers(SpirvHeader header, bool computeBounds, params Span<SpirvBuffer> buffers)
    {
        int instructionsMemorySize = 0;
        var bound = header.Bound;
        foreach (var buffer in buffers)
        {
            foreach (var i in buffer)
            {

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