llama: move suppress_tokens handling to common/sampling (#26276)

* llama: move suppress_tokens handling to common/sampling

* address security issues

* rm has_logit_bias
This commit is contained in:
Xuan-Son Nguyen 2026-07-29 18:02:30 +02:00 committed by GitHub
parent caa596ab3f
commit afeebe103b
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GPG key ID: B5690EEEBB952194
5 changed files with 32 additions and 44 deletions

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@ -142,33 +142,6 @@ static ggml_tensor * ggml_view_2d_slice(ggml_context * ctx0, ggml_tensor * x, in
idx * x->ne[0] * x->ne[1] * ggml_element_size(x));
}
// TODO @ngxson : maybe improve this in the future
class llm_graph_input_logits_bias : public llm_graph_input_i {
public:
llm_graph_input_logits_bias(const llama_vocab & vocab) {
arr.resize(vocab.n_tokens(), 0.0f);
for (llama_token id : vocab.get_suppress_tokens()) {
if (0 <= id && id < (int32_t)vocab.n_tokens()) {
arr[id] = -INFINITY;
}
}
}
virtual ~llm_graph_input_logits_bias() = default;
void set_input(const llama_ubatch * /*ubatch*/) override {
const int64_t n_vocab = arr.size();
ggml_backend_tensor_set(logits_bias, arr.data(), 0, n_vocab*ggml_element_size(logits_bias));
}
bool can_reuse(const llm_graph_params & /*params*/) override {
return true;
}
ggml_tensor * logits_bias = nullptr; // F32 [n_vocab]
std::vector<float> arr;
};
llama_model_gemma4::graph::graph(const llama_model & model, const llm_graph_params & params) :
llm_graph_context(params),
model(model),
@ -429,16 +402,6 @@ llama_model_gemma4::graph::graph(const llama_model & model, const llm_graph_para
cur = ggml_scale(ctx0, cur, hparams.f_final_logit_softcapping);
}
// apply logits bias if needed (e.g. for gemma4_unified patch)
// this is to mirror the suppress_tokens patch on transformers, to avoid model from outputing <image|> and <audio|> tokens (which is a known issue related to the checkpoint)
// TODO: maybe handle this inside the sampling system in the future
if (!model.vocab.get_suppress_tokens().empty()) {
auto inp_bias = std::make_unique<llm_graph_input_logits_bias>(model.vocab);
inp_bias->logits_bias = ggml_new_tensor_1d(ctx0, GGML_TYPE_F32, inp_bias->arr.size());
cur = ggml_add(ctx0, cur, inp_bias->logits_bias);
res->add_input(std::move(inp_bias));
}
cb(cur, "result_output", -1);
res->t_logits = cur;