[llvm-commits] CVS: llvm/include/llvm/Target/SubtargetFeature.h

[Jim Laskey]

Changes in directory llvm/include/llvm/Target:

SubtargetFeature.h added (r1.1)
---
Log message:

This new class provides support for platform specific "features".  The intent
is to manage processor specific attributes from the command line.  See examples
of use in llc/lli and PowerPCTargetSubtarget.



---
Diffs of the changes:  (+145 -0)

 SubtargetFeature.h |  145 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 145 insertions(+)


Index: llvm/include/llvm/Target/SubtargetFeature.h
diff -c /dev/null llvm/include/llvm/Target/SubtargetFeature.h:1.1
*** /dev/null	Thu Sep  1 16:36:28 2005
--- llvm/include/llvm/Target/SubtargetFeature.h	Thu Sep  1 16:36:18 2005
***************
*** 0 ****
--- 1,145 ----
+ //===-- llvm/Target/SubtargetFeature.h - CPU characteristics ----*- C++ -*-===//
+ //
+ //                     The LLVM Compiler Infrastructure
+ //
+ // This file was developed by Jim Laskey and is distributed under the 
+ // University of Illinois Open Source License. See LICENSE.TXT for details.
+ //
+ //===----------------------------------------------------------------------===//
+ //
+ // This file defines and manages user or tool specified CPU characteristics.
+ // The intent is to be able to package specific features that should or should
+ // not be used on a specific target processor.  A tool, such as llc, could, as
+ // as example, gather chip info from the command line, a long with features
+ // that should be used on that chip.
+ //
+ //===----------------------------------------------------------------------===//
+ 
+ #ifndef LLVM_TARGET_SUBTARGETFEATURE_H
+ #define LLVM_TARGET_SUBTARGETFEATURE_H
+ 
+ 
+ #include <string>
+ #include <vector>
+ #include <iostream>
+ #include <cassert>
+ 
+ namespace llvm {
+ 
+ //===----------------------------------------------------------------------===//
+ ///
+ /// SubtargetFeatureKV - Used to provide key value pairs for feature and
+ /// CPU bit flags.
+ //
+ struct SubtargetFeatureKV {
+   const char *Key;                      // K-V key string
+   uint32_t Value;                       // K-V integer value
+   
+   // Compare routine for std binary search
+   bool operator<(const std::string &S) const {
+     return strcmp(Key, S.c_str()) < 0;
+   }
+ };
+   
+ //===----------------------------------------------------------------------===//
+ ///
+ /// SubtargetFeatures - Manages the enabling and disabling of subtarget 
+ /// specific features.  Features are encoded as a string of the form
+ ///   "cpu,+attr1,+attr2,-attr3,...,+attrN"
+ /// A comma separates each feature from the next (all lowercase.)
+ /// The first feature is always the CPU subtype (eg. pentiumm).  If the CPU
+ /// value is "generic" then the CPU subtype should be generic for the target.
+ /// Each of the remaining features is prefixed with + or - indicating whether
+ /// that feature should be enabled or disabled contrary to the cpu
+ /// specification.
+ ///
+ 
+ class SubtargetFeatures {
+ private:
+   std::vector<std::string> Features;    // Subtarget features as a vector
+ 
+   // Determine if a feature has a flag; '+' or '-'
+   static inline bool hasFlag(const std::string &Feature) {
+     assert(!Feature.empty() && "Empty string");
+     // Get first character
+     char Ch = Feature[0];
+     // Check if first character is '+' or '-' flag
+     return Ch == '+' || Ch =='-';
+   }
+   
+   // Return true if enable flag; '+'.
+   static inline bool isEnabled(const std::string &Feature) {
+     assert(!Feature.empty() && "Empty string");
+     // Get first character
+     char Ch = Feature[0];
+     // Check if first character is '+' for enabled
+     return Ch == '+';
+   }
+   
+   // Return a string with a prepended flag; '+' or '-'.
+   static inline std::string PrependFlag(const std::string &Feature,
+                                         bool IsEnabled) {
+     assert(!Feature.empty() && "Empty string");
+     if (hasFlag(Feature)) return Feature;
+     return std::string(IsEnabled ? "+" : "-") + Feature;
+   }
+   
+   // Return string stripped of flag.
+   static inline std::string StripFlag(const std::string &Feature) {
+     return hasFlag(Feature) ? Feature.substr(1) : Feature;
+   }
+ 
+   /// Splits a string of comma separated items in to a vector of strings.
+   static void Split(std::vector<std::string> &V, const std::string &S);
+   
+   /// Join a vector of strings into a string with a comma separating each
+   /// item.
+   static std::string Join(const std::vector<std::string> &V);
+   
+   /// Convert a string to lowercase.
+   static std::string toLower(const std::string &S);
+   
+   /// Find item in array using binary search.
+   static const SubtargetFeatureKV *Find(const std::string &S,
+                                         const SubtargetFeatureKV *A, size_t L);
+ 
+ public:
+   /// Ctor.
+   SubtargetFeatures(const std::string Initial = std::string()) {
+     // Break up string into separate features
+     Split(Features, Initial);
+   }
+ 
+   /// Features string accessors.
+   inline std::string getString() const { return Join(Features); }
+   void setString(const std::string &Initial) {
+     // Throw out old features
+     Features.clear();
+     // Break up string into separate features
+     Split(Features, toLower(Initial));
+   }
+ 
+   /// Setting CPU string.  Replaces previous setting.  Setting to "" clears CPU.
+   void setCPU(std::string String) { Features[0] = toLower(String); }
+   
+   /// Adding Features.
+   void AddFeature(const std::string &String, bool IsEnabled = true);
+ 
+   /// Parse feature string for quick usage.
+   static uint32_t Parse(const std::string &String,
+                         const std::string &DefaultCPU,
+                         const SubtargetFeatureKV *CPUTable,
+                         size_t CPUTableSize,
+                         const SubtargetFeatureKV *FeatureTable,
+                         size_t FeatureTableSize);
+   
+   /// Print feature string.
+   void print(std::ostream &OS) const;
+   
+   // Dump feature info.
+   void dump() const;
+ };
+ 
+ } // End namespace llvm
+ 
+ #endif