Add LLVM compatible functions

Author: gbaraldi

.gitignore

@@ -11,4 +11,3 @@ build/
 # OS files
 .DS_Store
 Thumbs.db
-

Makefile

@@ -58,7 +58,7 @@ LIBDIR = $(BUILDDIR)/lib
 BINDIR = $(BUILDDIR)/bin
 
 # Source files
-SOURCES = $(SRCDIR)/cpuid.cpp $(SRCDIR)/microarchitecture.cpp $(SRCDIR)/detect.cpp $(SRCDIR)/archspec_c.cpp
+SOURCES = $(SRCDIR)/cpuid.cpp $(SRCDIR)/microarchitecture.cpp $(SRCDIR)/detect.cpp $(SRCDIR)/archspec_c.cpp $(SRCDIR)/llvm_compat.cpp
 OBJECTS = $(patsubst $(SRCDIR)/%.cpp,$(OBJDIR)/%.o,$(SOURCES))
 
 # Library names

README.md

@@ -245,4 +245,3 @@ This library is dual-licensed under Apache-2.0 OR MIT, matching the original arc
 
 - Based on [archspec](https://github.com/archspec/archspec) by Lawrence Livermore National Security, LLC
 - Uses [nlohmann/json](https://github.com/nlohmann/json) for JSON parsing
-

include/archspec/archspec.hpp

@@ -8,5 +8,6 @@
 
 #include "microarchitecture.hpp"
 #include "detect.hpp"
+#include "llvm_compat.hpp"
 
 #endif // ARCHSPEC_HPP

include/archspec/llvm_compat.hpp

@@ -0,0 +1,81 @@
+// LLVM feature name compatibility layer
+// Maps archspec feature names to LLVM feature names
+
+#ifndef ARCHSPEC_LLVM_COMPAT_HPP
+#define ARCHSPEC_LLVM_COMPAT_HPP
+
+#include <string>
+#include <string_view>
+#include <set>
+#include <vector>
+
+namespace archspec {
+
+// Forward declaration
+class Microarchitecture;
+
+/**
+ * Map a single archspec feature name to LLVM feature name.
+ * Returns empty string if the feature should be filtered out (no LLVM equivalent).
+ * Returns the input unchanged if no mapping is needed.
+ *
+ * @param arch_family Architecture family ("x86_64", "aarch64", "ppc64le", "riscv64")
+ * @param feature The archspec feature name
+ * @return LLVM-compatible feature name, or empty string to filter
+ */
+std::string map_feature_to_llvm(std::string_view arch_family, std::string_view feature);
+
+/**
+ * Get all LLVM-compatible features for a microarchitecture.
+ * Handles mapping and filtering automatically.
+ *
+ * @param uarch The microarchitecture to get features for
+ * @return Set of LLVM-compatible feature names (without +/- prefix)
+ */
+std::set<std::string> get_llvm_features(const Microarchitecture& uarch);
+
+/**
+ * Get LLVM-compatible features as a comma-separated string with +prefix.
+ * Example: "+neon,+dotprod,+crc"
+ *
+ * @param uarch The microarchitecture to get features for
+ * @return Comma-separated feature string
+ */
+std::string get_llvm_features_string(const Microarchitecture& uarch);
+
+/**
+ * Map archspec CPU name to LLVM CPU name.
+ * Examples:
+ *   - "m4" (Apple) -> "apple-m4"
+ *   - "zen3" -> "znver3"
+ *
+ * @param uarch The microarchitecture
+ * @return LLVM-compatible CPU name
+ */
+std::string get_llvm_cpu_name(const Microarchitecture& uarch);
+
+/**
+ * Normalize a CPU name to archspec format (reverse of get_llvm_cpu_name).
+ * Examples:
+ *   - "apple-m4" -> "m4"
+ *   - "znver3" -> "zen3"
+ *
+ * @param arch_family Architecture family ("x86_64", "aarch64", etc.)
+ * @param llvm_name The LLVM CPU name
+ * @return archspec-compatible CPU name
+ */
+std::string normalize_cpu_name(std::string_view arch_family, std::string_view llvm_name);
+
+/**
+ * Look up a CPU by name (with normalization) and return its LLVM-compatible features.
+ * Tries both the given name and normalized versions.
+ *
+ * @param cpu_name CPU name (can be LLVM or archspec format)
+ * @param arch_family Architecture family for normalization
+ * @return LLVM-compatible feature string, or empty if CPU not found
+ */
+std::string get_llvm_features_for_cpu(std::string_view cpu_name, std::string_view arch_family);
+
+} // namespace archspec
+
+#endif // ARCHSPEC_LLVM_COMPAT_HPP