Method Validate

layers/gpuav/spirv/debug_printf_pass.cpp:623–904

Strictly speaking - the format given in GLSL_EXT_debug_printf is a client side implementation of SPIR-V NonSemantic.DebugPrintf There is nothing stopping someone from creating a debug printf implementation that goes `printf("Use this &q to print int", myInt)` but this requires both having a different HLL and Tool consuming it. Currently RenderDoc and the Validation Layers both follow the same synt

// Currently RenderDoc and the Validation Layers both follow the same syntax, but that also could possibly change.
// Therefore, we validate these here based on the VVL implementation only
bool DebugPrintfPass::Validate(const Function& current_function, const InstructionMeta& meta) {
    static const char* tag = "DEBUG-PRINTF-FORMATTING";

    struct ParamInfo {
        bool is_float = false;  // else int (don't attempt to validate unsigned vs signed here)
        bool is_64_bit = false;
        bool is_pointer = false;
        uint32_t vector_size = 0;  // zero == scalar
        char modifier[32];
    };

    // where we find the first arugment in OpExtInst instruction
    const uint32_t first_argument_offset = 6;

    if (meta.target_instruction->Length() < first_argument_offset) {
        module_.InternalError(tag, "OpExtInst in a invalid SPIR-V format and should have been caught in spirv-val");
        return false;
    }

    uint32_t string_id = meta.target_instruction->Word(5);
    const char* op_string = nullptr;
    for (const auto& inst : module_.debug_source_) {
        if (inst->Opcode() == spv::OpString && inst->ResultId() == string_id) {
            op_string = inst->GetAsString(2);
            break;
        }
    }
    if (!op_string) {
        module_.InternalError(tag, "OpExtInst points to an empty/invalid OpString, this should have been caught in spirv-val");
        return false;
    }

    const size_t op_string_len = strlen(op_string);
    if (op_string_len == 0) {
        module_.InternalError(tag, "OpString is empty (string was found, but is empty)");
        return false;
    }

    // If we are going to print the OpString to the user for an error/warning, we need to process it first
    auto print_op_string = [&op_string]() {
        // If there is a '\n' we want to print it like we see in the shader, so need to escape the backslash
        std::string result;
        for (const char* p = op_string; *p != '\0'; ++p) {
            if (*p == '\n') {
                result += "\\n";
            } else if (*p == '\t') {
                result += "\\t";
            } else {
                result += *p;
            }
        }
        return result;
    };

    bool valid = true;
    std::vector<ParamInfo> param_infos;

    // No reason to start checking at the last character, since always need % and something following it