Merge pull request #4551 from danieldk/system-features-compute-level

Add x86_64 compute levels as system features

3 files changed, 91 insertions, 0 deletions

diff --git a/src/libutil/compute-levels.cc b/src/libutil/compute-levels.cc
new file mode 100644
index 000000000..19eaedfa8
--- /dev/null
+++ b/src/libutil/compute-levels.cc
@@ -0,0 +1,80 @@
+#include "types.hh"
+
+#if HAVE_LIBCPUID
+#include <libcpuid/libcpuid.h>
+#endif
+
+namespace nix {
+
+#if HAVE_LIBCPUID
+
+StringSet computeLevels() {
+    StringSet levels;
+
+    if (!cpuid_present())
+        return levels;
+
+    cpu_raw_data_t raw;
+    cpu_id_t data;
+
+    if (cpuid_get_raw_data(&raw) < 0)
+        return levels;
+
+    if (cpu_identify(&raw, &data) < 0)
+        return levels;
+
+    if (!(data.flags[CPU_FEATURE_CMOV] &&
+            data.flags[CPU_FEATURE_CX8] &&
+            data.flags[CPU_FEATURE_FPU] &&
+            data.flags[CPU_FEATURE_FXSR] &&
+            data.flags[CPU_FEATURE_MMX] &&
+            data.flags[CPU_FEATURE_SSE] &&
+            data.flags[CPU_FEATURE_SSE2]))
+        return levels;
+
+    levels.insert("x86_64-v1");
+
+    if (!(data.flags[CPU_FEATURE_CX16] &&
+            data.flags[CPU_FEATURE_LAHF_LM] &&
+            data.flags[CPU_FEATURE_POPCNT] &&
+            // SSE3
+            data.flags[CPU_FEATURE_PNI] &&
+            data.flags[CPU_FEATURE_SSSE3] &&
+            data.flags[CPU_FEATURE_SSE4_1] &&
+            data.flags[CPU_FEATURE_SSE4_2]))
+        return levels;
+
+    levels.insert("x86_64-v2");
+
+    if (!(data.flags[CPU_FEATURE_AVX] &&
+            data.flags[CPU_FEATURE_AVX2] &&
+            data.flags[CPU_FEATURE_F16C] &&
+            data.flags[CPU_FEATURE_FMA3] &&
+            // LZCNT
+            data.flags[CPU_FEATURE_ABM] &&
+            data.flags[CPU_FEATURE_MOVBE]))
+        return levels;
+
+    levels.insert("x86_64-v3");
+
+    if (!(data.flags[CPU_FEATURE_AVX512F] &&
+            data.flags[CPU_FEATURE_AVX512BW] &&
+            data.flags[CPU_FEATURE_AVX512CD] &&
+            data.flags[CPU_FEATURE_AVX512DQ] &&
+            data.flags[CPU_FEATURE_AVX512VL]))
+        return levels;
+
+    levels.insert("x86_64-v4");
+
+    return levels;
+}
+
+#else
+
+StringSet computeLevels() {
+    return StringSet{};
+}
+
+#endif // HAVE_LIBCPUID
+
+}
diff --git a/src/libutil/compute-levels.hh b/src/libutil/compute-levels.hh
new file mode 100644
index 000000000..8ded295f9
--- /dev/null
+++ b/src/libutil/compute-levels.hh
@@ -0,0 +1,7 @@
+#include "types.hh"
+
+namespace nix {
+
+StringSet computeLevels();
+
+}
diff --git a/src/libutil/local.mk b/src/libutil/local.mk
index ae7eb67ad..5341c58e6 100644
--- a/src/libutil/local.mk
+++ b/src/libutil/local.mk
@@ -7,3 +7,7 @@ libutil_DIR := $(d)
 libutil_SOURCES := $(wildcard $(d)/*.cc)
 
 libutil_LDFLAGS = $(LIBLZMA_LIBS) -lbz2 -pthread $(OPENSSL_LIBS) $(LIBBROTLI_LIBS) $(LIBARCHIVE_LIBS) $(BOOST_LDFLAGS) -lboost_context
+
+ifeq ($(HAVE_LIBCPUID), 1)
+	libutil_LDFLAGS += -lcpuid
+endif