ROCm: Allow setting compilation target (vllm-project#2581)

Author: rlrs

setup.py

@@ -287,11 +287,15 @@ def get_torch_arch_list() -> Set[str]:
                 },
             ))
 elif _is_hip():
-    amd_arch = get_amdgpu_offload_arch()
-    if amd_arch not in ROCM_SUPPORTED_ARCHS:
-        raise RuntimeError(
-            f"Only the following arch is supported: {ROCM_SUPPORTED_ARCHS}"
-            f"amdgpu_arch_found: {amd_arch}")
+    amd_archs = os.getenv("GPU_ARCHS")
+    if amd_archs is None:
+        amd_archs = get_amdgpu_offload_arch()
+    for arch in amd_archs.split(";"):
+        if arch not in ROCM_SUPPORTED_ARCHS:
+            raise RuntimeError(
+                f"Only the following arch is supported: {ROCM_SUPPORTED_ARCHS}"
+                f"amdgpu_arch_found: {arch}")
+        NVCC_FLAGS += [f"--offload-arch={arch}"]
 
 elif _is_neuron():
     neuronxcc_version = get_neuronxcc_version()