Hotfixes for santacoder/bigcode. (#294)

# What does this PR do?

Hotfixes:

- Uses `model_type`=`gpt_bigcode` for more general usage.
- Hotfixes linked lm_head vs wte_embedding (safetensors file do not
contain the key, correctly when the file is sharded, where as pytorch
copies the tensor)


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Fixes # (issue)


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---------
Co-authored-by: Ubuntu <ubuntu@ip-172-31-41-161.ec2.internal>
Co-authored-by: OlivierDehaene <olivier@huggingface.co>

server/text_generation_server/models/__init__.py

@@ -99,7 +99,7 @@ def get_model(
         else:
             return Galactica(model_id, revision, quantize=quantize)
 
-    if "bigcode" in model_id:
+    if model_id.startswith("bigcode/"):
         if sharded:
             if not FLASH_ATTENTION:
                 raise NotImplementedError(
@@ -113,6 +113,17 @@ def get_model(
     config = AutoConfig.from_pretrained(model_id, revision=revision)
     model_type = config.model_type
 
+    if model_type == "gpt_bigcode":
+        if sharded:
+            if not FLASH_ATTENTION:
+                raise NotImplementedError(
+                    FLASH_ATT_ERROR_MESSAGE.format(f"Sharded Santacoder")
+                )
+            return FlashSantacoderSharded(model_id, revision, quantize=quantize)
+        else:
+            santacoder_cls = FlashSantacoder if FLASH_ATTENTION else SantaCoder
+            return santacoder_cls(model_id, revision, quantize=quantize)
+
     if model_type == "bloom":
         if sharded:
             return BLOOMSharded(model_id, revision, quantize=quantize)

server/text_generation_server/models/flash_santacoder.py

@@ -376,6 +376,9 @@ class FlashSantacoderSharded(FlashSantacoder):
                     else:
                         module._buffers[param_name] = tensor
 
+
+        model.lm_head.weight = torch.nn.Parameter(model.transformer.wte.weight)
+
         uninitialized_parameters = []
         for n, p in model.named_parameters():
             if p.data.device == torch.device("meta"):