llvm/lib/Target/SubtargetFeature.cpp
Bill Wendling 4222d806fa Add an "implies" field to features. This indicates that, if the current
feature is set, then the features in the implied list should be set also.
The opposite is also enforced: if a feature in the implied list isn't set,
then the feature that owns that implies list shouldn't be set either.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@36756 91177308-0d34-0410-b5e6-96231b3b80d8
2007-05-04 20:38:40 +00:00

351 lines
11 KiB
C++

//===- SubtargetFeature.cpp - CPU characteristics Implementation ----------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by James M. Laskey and is distributed under the
// University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the SubtargetFeature interface.
//
//===----------------------------------------------------------------------===//
#include "llvm/Target/SubtargetFeature.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Support/Streams.h"
#include <algorithm>
#include <ostream>
#include <cassert>
#include <cctype>
using namespace llvm;
//===----------------------------------------------------------------------===//
// Static Helper Functions
//===----------------------------------------------------------------------===//
/// hasFlag - 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 =='-';
}
/// StripFlag - Return string stripped of flag.
///
static inline std::string StripFlag(const std::string &Feature) {
return hasFlag(Feature) ? Feature.substr(1) : Feature;
}
/// isEnabled - 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 == '+';
}
/// PrependFlag - 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;
}
/// Split - 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) {
// Start at beginning of string.
size_t Pos = 0;
while (true) {
// Find the next comma
size_t Comma = S.find(',', Pos);
// If no comma found then the the rest of the string is used
if (Comma == std::string::npos) {
// Add string to vector
V.push_back(S.substr(Pos));
break;
}
// Otherwise add substring to vector
V.push_back(S.substr(Pos, Comma - Pos));
// Advance to next item
Pos = Comma + 1;
}
}
/// Join a vector of strings to a string with a comma separating each element.
///
static std::string Join(const std::vector<std::string> &V) {
// Start with empty string.
std::string Result;
// If the vector is not empty
if (!V.empty()) {
// Start with the CPU feature
Result = V[0];
// For each successive feature
for (size_t i = 1; i < V.size(); i++) {
// Add a comma
Result += ",";
// Add the feature
Result += V[i];
}
}
// Return the features string
return Result;
}
/// Adding features.
void SubtargetFeatures::AddFeature(const std::string &String,
bool IsEnabled) {
// Don't add empty features
if (!String.empty()) {
// Convert to lowercase, prepend flag and add to vector
Features.push_back(PrependFlag(LowercaseString(String), IsEnabled));
}
}
/// Find KV in array using binary search.
template<typename T> const T *Find(const std::string &S, const T *A, size_t L) {
// Make the lower bound element we're looking for
T KV;
KV.Key = S.c_str();
// Determine the end of the array
const T *Hi = A + L;
// Binary search the array
const T *F = std::lower_bound(A, Hi, KV);
// If not found then return NULL
if (F == Hi || std::string(F->Key) != S) return NULL;
// Return the found array item
return F;
}
/// getLongestEntryLength - Return the length of the longest entry in the table.
///
static size_t getLongestEntryLength(const SubtargetFeatureKV *Table,
size_t Size) {
size_t MaxLen = 0;
for (size_t i = 0; i < Size; i++)
MaxLen = std::max(MaxLen, std::strlen(Table[i].Key));
return MaxLen;
}
/// Display help for feature choices.
///
static void Help(const SubtargetFeatureKV *CPUTable, size_t CPUTableSize,
const SubtargetFeatureKV *FeatTable, size_t FeatTableSize) {
// Determine the length of the longest CPU and Feature entries.
unsigned MaxCPULen = getLongestEntryLength(CPUTable, CPUTableSize);
unsigned MaxFeatLen = getLongestEntryLength(FeatTable, FeatTableSize);
// Print the CPU table.
cerr << "Available CPUs for this target:\n\n";
for (size_t i = 0; i != CPUTableSize; i++)
cerr << " " << CPUTable[i].Key
<< std::string(MaxCPULen - std::strlen(CPUTable[i].Key), ' ')
<< " - " << CPUTable[i].Desc << ".\n";
cerr << "\n";
// Print the Feature table.
cerr << "Available features for this target:\n\n";
for (size_t i = 0; i != FeatTableSize; i++)
cerr << " " << FeatTable[i].Key
<< std::string(MaxFeatLen - std::strlen(FeatTable[i].Key), ' ')
<< " - " << FeatTable[i].Desc << ".\n";
cerr << "\n";
cerr << "Use +feature to enable a feature, or -feature to disable it.\n"
<< "For example, llc -mcpu=mycpu -mattr=+feature1,-feature2\n";
exit(1);
}
//===----------------------------------------------------------------------===//
// SubtargetFeatures Implementation
//===----------------------------------------------------------------------===//
SubtargetFeatures::SubtargetFeatures(const std::string &Initial) {
// Break up string into separate features
Split(Features, Initial);
}
std::string SubtargetFeatures::getString() const {
return Join(Features);
}
void SubtargetFeatures::setString(const std::string &Initial) {
// Throw out old features
Features.clear();
// Break up string into separate features
Split(Features, LowercaseString(Initial));
}
/// setCPU - Set the CPU string. Replaces previous setting. Setting to ""
/// clears CPU.
void SubtargetFeatures::setCPU(const std::string &String) {
Features[0] = LowercaseString(String);
}
/// setCPUIfNone - Setting CPU string only if no string is set.
///
void SubtargetFeatures::setCPUIfNone(const std::string &String) {
if (Features[0].empty()) setCPU(String);
}
/// SetImpliedBits - For each feature that is (transitively) implied by this
/// feature, set it.
///
static
void SetImpliedBits(uint32_t &Bits, const SubtargetFeatureKV *FeatureEntry,
const SubtargetFeatureKV *FeatureTable,
size_t FeatureTableSize) {
for (size_t i = 0; i < FeatureTableSize; ++i) {
const SubtargetFeatureKV &FE = FeatureTable[i];
if (FeatureEntry->Value == FE.Value) continue;
if (FeatureEntry->Implies & FE.Value) {
Bits |= FE.Value;
SetImpliedBits(Bits, &FE, FeatureTable, FeatureTableSize);
}
}
}
/// ClearImpliedBits - For each feature that (transitively) implies this
/// feature, clear it.
///
static
void ClearImpliedBits(uint32_t &Bits, const SubtargetFeatureKV *FeatureEntry,
const SubtargetFeatureKV *FeatureTable,
size_t FeatureTableSize) {
for (size_t i = 0; i < FeatureTableSize; ++i) {
const SubtargetFeatureKV &FE = FeatureTable[i];
if (FeatureEntry->Value == FE.Value) continue;
if (FE.Implies & FeatureEntry->Value) {
Bits &= ~FE.Value;
ClearImpliedBits(Bits, &FE, FeatureTable, FeatureTableSize);
}
}
}
/// getBits - Get feature bits.
///
uint32_t SubtargetFeatures::getBits(const SubtargetFeatureKV *CPUTable,
size_t CPUTableSize,
const SubtargetFeatureKV *FeatureTable,
size_t FeatureTableSize) {
assert(CPUTable && "missing CPU table");
assert(FeatureTable && "missing features table");
#ifndef NDEBUG
for (size_t i = 1; i < CPUTableSize; i++) {
assert(strcmp(CPUTable[i - 1].Key, CPUTable[i].Key) < 0 &&
"CPU table is not sorted");
}
for (size_t i = 1; i < FeatureTableSize; i++) {
assert(strcmp(FeatureTable[i - 1].Key, FeatureTable[i].Key) < 0 &&
"CPU features table is not sorted");
}
#endif
uint32_t Bits = 0; // Resulting bits
// Check if help is needed
if (Features[0] == "help")
Help(CPUTable, CPUTableSize, FeatureTable, FeatureTableSize);
// Find CPU entry
const SubtargetFeatureKV *CPUEntry =
Find(Features[0], CPUTable, CPUTableSize);
// If there is a match
if (CPUEntry) {
// Set base feature bits
Bits = CPUEntry->Value;
} else {
cerr << "'" << Features[0]
<< "' is not a recognized processor for this target"
<< " (ignoring processor)"
<< "\n";
}
// Iterate through each feature
for (size_t i = 1; i < Features.size(); i++) {
const std::string &Feature = Features[i];
// Check for help
if (Feature == "+help")
Help(CPUTable, CPUTableSize, FeatureTable, FeatureTableSize);
// Find feature in table.
const SubtargetFeatureKV *FeatureEntry =
Find(StripFlag(Feature), FeatureTable, FeatureTableSize);
// If there is a match
if (FeatureEntry) {
// Enable/disable feature in bits
if (isEnabled(Feature)) {
Bits |= FeatureEntry->Value;
// For each feature that this implies, set it.
SetImpliedBits(Bits, FeatureEntry, FeatureTable, FeatureTableSize);
} else {
Bits &= ~FeatureEntry->Value;
// For each feature that implies this, clear it.
ClearImpliedBits(Bits, FeatureEntry, FeatureTable, FeatureTableSize);
}
} else {
cerr << "'" << Feature
<< "' is not a recognized feature for this target"
<< " (ignoring feature)"
<< "\n";
}
}
return Bits;
}
/// Get info pointer
void *SubtargetFeatures::getInfo(const SubtargetInfoKV *Table,
size_t TableSize) {
assert(Table && "missing table");
#ifndef NDEBUG
for (size_t i = 1; i < TableSize; i++) {
assert(strcmp(Table[i - 1].Key, Table[i].Key) < 0 && "Table is not sorted");
}
#endif
// Find entry
const SubtargetInfoKV *Entry = Find(Features[0], Table, TableSize);
if (Entry) {
return Entry->Value;
} else {
cerr << "'" << Features[0]
<< "' is not a recognized processor for this target"
<< " (ignoring processor)"
<< "\n";
return NULL;
}
}
/// print - Print feature string.
///
void SubtargetFeatures::print(std::ostream &OS) const {
for (size_t i = 0; i < Features.size(); i++) {
OS << Features[i] << " ";
}
OS << "\n";
}
/// dump - Dump feature info.
///
void SubtargetFeatures::dump() const {
print(*cerr.stream());
}