isl_map_coalesce: avoid ignoring constraints redundant wrt implicit equalities

[isl.git] / interface / generator.cc

/*
 * Copyright 2011,2015 Sven Verdoolaege. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *    1. Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *
 *    2. Redistributions in binary form must reproduce the above
 *       copyright notice, this list of conditions and the following
 *       disclaimer in the documentation and/or other materials provided
 *       with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY SVEN VERDOOLAEGE ''AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL SVEN VERDOOLAEGE OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
 * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * The views and conclusions contained in the software and documentation
 * are those of the authors and should not be interpreted as
 * representing official policies, either expressed or implied, of
 * Sven Verdoolaege.
 */

#include <stdio.h>
#include <string.h>
#include <algorithm>
#include <iostream>

#include <clang/AST/Attr.h>
#include <clang/Basic/SourceManager.h>

#include "isl_config.h"
#include "extract_interface.h"
#include "generator.h"

const char *isl_class::get_prefix = "get_";
const char *isl_class::set_callback_prefix = "set_";

/* Is the first argument an instance of the class?
 */
bool isl_class::first_arg_matches_class(FunctionDecl *method) const
{
        ParmVarDecl *param;
        QualType type;

        if (method->getNumParams() < 1)
                return false;

        param = method->getParamDecl(0);
        type = param->getOriginalType();
        if (!generator::is_isl_type(type))
                return false;
        return generator::extract_type(type) == name;
}

/* Should "method" be considered to be a static method?
 * That is, is the first argument something other than
 * an instance of the class?
 *
 * If this method was copied from a superclass, then check
 * whether the method is static with respect to this superclass.
 */
bool isl_class::is_static(FunctionDecl *method) const
{
        if (copied_from.count(method) != 0)
                return copied_from.at(method).is_static(method);
        return !first_arg_matches_class(method);
}

/* Should "method" be considered to be a static method?
 * That is, is the first argument something other than
 * an instance of the class?
 */
bool generator::is_static(const isl_class &clazz, FunctionDecl *method)
{
        return clazz.is_static(method);
}

/* Does "fd" modify an object of "clazz"?
 * That is, is it an object method that takes the object and
 * returns (gives) an object of the same type?
 */
bool generator::is_mutator(const isl_class &clazz, FunctionDecl *fd)
{
        ParmVarDecl *param;
        QualType type, return_type;

        if (fd->getNumParams() < 1)
                return false;
        if (is_static(clazz, fd))
                return false;

        if (!gives(fd))
                return false;
        param = fd->getParamDecl(0);
        if (!takes(param))
                return false;
        type = param->getOriginalType();
        return_type = fd->getReturnType();
        return return_type == type;
}

/* Find the FunctionDecl with name "name",
 * returning NULL if there is no such FunctionDecl.
 * If "required" is set, then error out if no FunctionDecl can be found.
 */
FunctionDecl *generator::find_by_name(const string &name, bool required)
{
        map<string, FunctionDecl *>::iterator i;

        i = functions_by_name.find(name);
        if (i != functions_by_name.end())
                return i->second;
        if (required)
                die("No " + name + " function found");
        return NULL;
}

/* List of conversion functions that are used to automatically convert
 * the second argument of the conversion function to its function result.
 */
const std::set<std::string> generator::automatic_conversion_functions = {
        "isl_id_read_from_str",
        "isl_val_int_from_si",
};

/* Extract information about the automatic conversion function "fd",
 * storing the results in this->conversions.
 *
 * A function used for automatic conversion has exactly two arguments,
 * an isl_ctx and a non-isl object, and it returns an isl object.
 * Store a mapping from the isl object return type
 * to the non-isl object source type.
 */
void generator::extract_automatic_conversion(FunctionDecl *fd)
{
        QualType return_type = fd->getReturnType();
        const Type *type = return_type.getTypePtr();

        if (fd->getNumParams() != 2)
                die("Expecting two arguments");
        if (!is_isl_ctx(fd->getParamDecl(0)->getOriginalType()))
                die("Expecting isl_ctx first argument");
        if (!is_isl_type(return_type))
                die("Expecting isl object return type");
        conversions[type] = fd->getParamDecl(1);
}

/* Extract information about all automatic conversion functions
 * for the given class, storing the results in this->conversions.
 *
 * In particular, look through all exported constructors for the class and
 * check if any of them is explicitly marked as a conversion function.
 */
void generator::extract_class_automatic_conversions(const isl_class &clazz)
{
        const function_set &constructors = clazz.constructors;
        function_set::iterator fi;

        for (fi = constructors.begin(); fi != constructors.end(); ++fi) {
                FunctionDecl *fd = *fi;
                string name = fd->getName().str();
                if (automatic_conversion_functions.count(name) != 0)
                        extract_automatic_conversion(fd);
        }
}

/* Extract information about all automatic conversion functions,
 * storing the results in this->conversions.
 */
void generator::extract_automatic_conversions()
{
        map<string, isl_class>::iterator ci;

        for (ci = classes.begin(); ci != classes.end(); ++ci)
                extract_class_automatic_conversions(ci->second);
}

/* Add a subclass derived from "decl" called "sub_name" to the set of classes,
 * keeping track of the _to_str, _copy and _free functions, if any, separately.
 * "sub_name" is either the name of the class itself or
 * the name of a type based subclass.
 * If the class is a proper subclass, then "super_name" is the name
 * of its immediate superclass.
 */
void generator::add_subclass(RecordDecl *decl, const string &super_name,
        const string &sub_name)
{
        string name = decl->getName().str();

        classes[sub_name].name = name;
        classes[sub_name].superclass_name = super_name;
        classes[sub_name].subclass_name = sub_name;
        classes[sub_name].type = decl;
        classes[sub_name].fn_to_str = find_by_name(name + "_to_str", false);
        classes[sub_name].fn_copy = find_by_name(name + "_copy", true);
        classes[sub_name].fn_free = find_by_name(name + "_free", true);
}

/* Add a class derived from "decl" to the set of classes,
 * keeping track of the _to_str, _copy and _free functions, if any, separately.
 */
void generator::add_class(RecordDecl *decl)
{
        return add_subclass(decl, "", decl->getName().str());
}

/* Given a function "fn_type" that returns the subclass type
 * of a C object, create subclasses for each of the (non-negative)
 * return values.
 *
 * The function "fn_type" is also stored in the superclass,
 * along with all pairs of type values and subclass names.
 */
void generator::add_type_subclasses(FunctionDecl *fn_type)
{
        QualType return_type = fn_type->getReturnType();
        const EnumType *enum_type = return_type->getAs<EnumType>();
        EnumDecl *decl = enum_type->getDecl();
        isl_class *c = method2class(fn_type);
        DeclContext::decl_iterator i;

        c->fn_type = fn_type;
        for (i = decl->decls_begin(); i != decl->decls_end(); ++i) {
                EnumConstantDecl *ecd = dyn_cast<EnumConstantDecl>(*i);
                int val = (int) ecd->getInitVal().getSExtValue();
                string name = ecd->getNameAsString();

                if (val < 0)
                        continue;
                c->type_subclasses[val] = name;
                add_subclass(c->type, c->subclass_name, name);
        }
}

/* Add information about the enum values in "decl", set by "fd",
 * to c->set_enums. "prefix" is the prefix of the generated method names.
 * In particular, it has the name of the enum type removed.
 *
 * In particular, for each non-negative enum value, keep track of
 * the value, the name and the corresponding method name.
 */
static void add_set_enum(isl_class *c, const string &prefix, EnumDecl *decl,
        FunctionDecl *fd)
{
        DeclContext::decl_iterator i;

        for (i = decl->decls_begin(); i != decl->decls_end(); ++i) {
                EnumConstantDecl *ecd = dyn_cast<EnumConstantDecl>(*i);
                int val = (int) ecd->getInitVal().getSExtValue();
                string name = ecd->getNameAsString();
                string method_name;

                if (val < 0)
                        continue;
                method_name = prefix + name.substr(4);
                c->set_enums[fd].push_back(set_enum(val, name, method_name));
        }
}

/* Check if "fd" sets an enum value and, if so, add information
 * about the enum values to c->set_enums.
 *
 * A function is considered to set an enum value if:
 * - the function returns an object of the same type
 * - the last argument is of type enum
 * - the name of the function ends with the name of the enum
 */
static bool handled_sets_enum(isl_class *c, FunctionDecl *fd)
{
        unsigned n;
        ParmVarDecl *param;
        const EnumType *enum_type;
        EnumDecl *decl;
        string enum_name;
        string fd_name;
        string prefix;
        size_t pos;

        if (!generator::is_mutator(*c, fd))
                return false;
        n = fd->getNumParams();
        if (n < 2)
                return false;
        param = fd->getParamDecl(n - 1);
        enum_type = param->getType()->getAs<EnumType>();
        if (!enum_type)
                return false;
        decl = enum_type->getDecl();
        enum_name = decl->getName().str();
        enum_name = enum_name.substr(4);
        fd_name = c->method_name(fd);
        pos = fd_name.find(enum_name);
        if (pos == std::string::npos)
                return false;
        prefix = fd_name.substr(0, pos);

        add_set_enum(c, prefix, decl, fd);

        return true;
}

/* Return the callback argument of a function setting
 * a persistent callback.
 * This callback is in the second argument (position 1).
 */
ParmVarDecl *generator::persistent_callback_arg(FunctionDecl *fd)
{
        return fd->getParamDecl(1);
}

/* Does the given function set a persistent callback?
 * The following heuristics are used to determine this property:
 * - the function returns an object of the same type
 * - its name starts with "set_"
 * - it has exactly three arguments
 * - the second (position 1) of which is a callback
 */
static bool sets_persistent_callback(isl_class *c, FunctionDecl *fd)
{
        ParmVarDecl *param;

        if (!generator::is_mutator(*c, fd))
                return false;
        if (fd->getNumParams() != 3)
                return false;
        param = generator::persistent_callback_arg(fd);
        if (!generator::is_callback(param->getType()))
                return false;
        return prefixcmp(c->method_name(fd).c_str(),
                         c->set_callback_prefix) == 0;
}

/* Does this function take any enum arguments?
 */
static bool takes_enums(FunctionDecl *fd)
{
        unsigned n;

        n = fd->getNumParams();
        for (unsigned i = 0; i < n; ++i) {
                ParmVarDecl *param = fd->getParamDecl(i);
                if (param->getType()->getAs<EnumType>())
                        return true;
        }
        return false;
}

/* Sorting function that places declaration of functions
 * with a shorter name first.
 */
static bool less_name(const FunctionDecl *a, const FunctionDecl *b)
{
        return a->getName().size() < b->getName().size();
}

/* Collect all functions that belong to a certain type, separating
 * constructors from methods that set an enum value,
 * methods that set a persistent callback and
 * from regular methods, while keeping track of the _to_str,
 * _copy and _free functions, if any, separately.
 * Methods that accept any enum arguments that are not specifically handled
 * are not supported.
 * If there are any overloaded
 * functions, then they are grouped based on their name after removing the
 * argument type suffix.
 * Check for functions that describe subclasses before considering
 * any other functions in order to be able to detect those other
 * functions as belonging to the subclasses.
 * Sort the names of the functions based on their lengths
 * to ensure that nested subclasses are handled later.
 *
 * Also extract information about automatic conversion functions.
 */
generator::generator(SourceManager &SM, set<RecordDecl *> &exported_types,
        set<FunctionDecl *> exported_functions, set<FunctionDecl *> functions) :
        SM(SM)
{
        set<FunctionDecl *>::iterator in;
        set<RecordDecl *>::iterator it;
        vector<FunctionDecl *> type_subclasses;
        vector<FunctionDecl *>::iterator iv;

        for (in = functions.begin(); in != functions.end(); ++in) {
                FunctionDecl *decl = *in;
                functions_by_name[decl->getName().str()] = decl;
        }

        for (it = exported_types.begin(); it != exported_types.end(); ++it)
                add_class(*it);

        for (in = exported_functions.begin(); in != exported_functions.end();
             ++in) {
                if (is_subclass(*in))
                        type_subclasses.push_back(*in);
        }
        std::sort(type_subclasses.begin(), type_subclasses.end(), &less_name);
        for (iv = type_subclasses.begin(); iv != type_subclasses.end(); ++iv) {
                add_type_subclasses(*iv);
        }

        for (in = exported_functions.begin(); in != exported_functions.end();
             ++in) {
                FunctionDecl *method = *in;
                isl_class *c;

                if (is_subclass(method))
                        continue;

                c = method2class(method);
                if (!c)
                        continue;
                if (is_constructor(method)) {
                        c->constructors.insert(method);
                } else if (handled_sets_enum(c, method)) {
                } else if (sets_persistent_callback(c, method)) {
                        c->persistent_callbacks.insert(method);
                } else if (takes_enums(method)) {
                        std::string name = method->getName().str();
                        die(name + " has unhandled enum argument");
                } else {
                        string name = c->method_name(method);
                        c->methods[name].insert(method);
                }
        }

        extract_automatic_conversions();
}

/* Print error message "msg" and abort.
 */
void generator::die(const char *msg)
{
        fprintf(stderr, "%s\n", msg);
        abort();
}

/* Print error message "msg" and abort.
 */
void generator::die(string msg)
{
        die(msg.c_str());
}

/* Return a sequence of the types of which the given type declaration is
 * marked as being a subtype.
 * The order of the types is the opposite of the order in which they
 * appear in the source.  In particular, the first annotation
 * is the one that is closest to the annotated type and the corresponding
 * type is then also the first that will appear in the sequence of types.
 * This is also the order in which the annotations appear
 * in the AttrVec returned by Decl::getAttrs() in older versions of clang.
 * In newer versions of clang, the order is that in which
 * the attribute appears in the source.
 * Use the position of the "isl_export" attribute to determine
 * whether this is an old (with reversed order) or a new version.
 * The "isl_export" attribute is automatically added
 * after each "isl_subclass" attribute.  If it appears in the list before
 * any "isl_subclass" is encountered, then this must be a reversed list.
 */
std::vector<string> generator::find_superclasses(Decl *decl)
{
        vector<string> super;
        bool reversed = false;

        if (!decl->hasAttrs())
                return super;

        string sub = "isl_subclass";
        size_t len = sub.length();
        AttrVec attrs = decl->getAttrs();
        for (AttrVec::const_iterator i = attrs.begin(); i != attrs.end(); ++i) {
                const AnnotateAttr *ann = dyn_cast<AnnotateAttr>(*i);
                if (!ann)
                        continue;
                string s = ann->getAnnotation().str();
                if (s == "isl_export" && super.size() == 0)
                        reversed = true;
                if (s.substr(0, len) == sub) {
                        s = s.substr(len + 1, s.length() - len  - 2);
                        if (reversed)
                                super.push_back(s);
                        else
                                super.insert(super.begin(), s);
                }
        }

        return super;
}

/* Is "decl" marked as describing subclasses?
 */
bool generator::is_subclass(FunctionDecl *decl)
{
        return find_superclasses(decl).size() > 0;
}

/* Is decl marked as being part of an overloaded method?
 */
bool generator::is_overload(Decl *decl)
{
        return has_annotation(decl, "isl_overload");
}

/* Is decl marked as a constructor?
 */
bool generator::is_constructor(Decl *decl)
{
        return has_annotation(decl, "isl_constructor");
}

/* Is decl marked as consuming a reference?
 */
bool generator::takes(Decl *decl)
{
        return has_annotation(decl, "isl_take");
}

/* Is decl marked as preserving a reference?
 */
bool generator::keeps(Decl *decl)
{
        return has_annotation(decl, "isl_keep");
}

/* Is decl marked as returning a reference that is required to be freed.
 */
bool generator::gives(Decl *decl)
{
        return has_annotation(decl, "isl_give");
}

/* Return the class that has a name that best matches the initial part
 * of the name of function "fd" or NULL if no such class could be found.
 */
isl_class *generator::method2class(FunctionDecl *fd)
{
        string best;
        map<string, isl_class>::iterator ci;
        string name = fd->getNameAsString();

        for (ci = classes.begin(); ci != classes.end(); ++ci) {
                size_t len = ci->first.length();
                if (len > best.length() && name.substr(0, len) == ci->first &&
                    name[len] == '_')
                        best = ci->first;
        }

        if (classes.find(best) == classes.end()) {
                cerr << "Unable to find class of " << name << endl;
                return NULL;
        }

        return &classes[best];
}

/* Is "type" the type "isl_ctx *"?
 */
bool generator::is_isl_ctx(QualType type)
{
        if (!type->isPointerType())
                return false;
        type = type->getPointeeType();
        if (type.getAsString() != "isl_ctx")
                return false;

        return true;
}

/* Is the first argument of "fd" of type "isl_ctx *"?
 */
bool generator::first_arg_is_isl_ctx(FunctionDecl *fd)
{
        ParmVarDecl *param;

        if (fd->getNumParams() < 1)
                return false;

        param = fd->getParamDecl(0);
        return is_isl_ctx(param->getOriginalType());
}

namespace {

struct ClangAPI {
        /* Return the first location in the range returned by
         * clang::SourceManager::getImmediateExpansionRange.
         * Older versions of clang return a pair of SourceLocation objects.
         * More recent versions return a CharSourceRange.
         */
        static SourceLocation range_begin(
                        const std::pair<SourceLocation,SourceLocation> &p) {
                return p.first;
        }
        static SourceLocation range_begin(const CharSourceRange &range) {
                return range.getBegin();
        }
};

}

/* Does the callback argument "param" take its argument at position "pos"?
 *
 * The memory management annotations of arguments to function pointers
 * are not recorded by clang, so the information cannot be extracted
 * from the type of "param".
 * Instead, go to the location in the source where the callback argument
 * is declared, look for the right argument of the callback itself and
 * then check if it has an "__isl_take" memory management annotation.
 *
 * If the return value of the function has a memory management annotation,
 * then the spelling of "param" will point to the spelling
 * of this memory management annotation.  Since the macro is defined
 * on the command line (in main), this location does not have a file entry.
 * In this case, move up one level in the macro expansion to the location
 * where the memory management annotation is used.
 */
bool generator::callback_takes_argument(ParmVarDecl *param,
        int pos)
{
        SourceLocation loc;
        const char *s, *end, *next;
        bool takes, keeps;

        loc = param->getSourceRange().getBegin();
        if (!SM.getFileEntryForID(SM.getFileID(SM.getSpellingLoc(loc))))
                loc = ClangAPI::range_begin(SM.getImmediateExpansionRange(loc));
        s = SM.getCharacterData(loc);
        if (!s)
                die("No character data");
        s = strchr(s, '(');
        if (!s)
                die("Cannot find function pointer");
        s = strchr(s + 1, '(');
        if (!s)
                die("Cannot find function pointer arguments");
        end = strchr(s + 1, ')');
        if (!end)
                die("Cannot find end of function pointer arguments");
        while (pos-- > 0) {
                s = strchr(s + 1, ',');
                if (!s || s > end)
                        die("Cannot find function pointer argument");
        }
        next = strchr(s + 1, ',');
        if (next && next < end)
                end = next;
        s = strchr(s + 1, '_');
        if (!s || s > end)
                die("Cannot find function pointer argument annotation");
        takes = prefixcmp(s, "__isl_take") == 0;
        keeps = prefixcmp(s, "__isl_keep") == 0;
        if (!takes && !keeps)
                die("Cannot find function pointer argument annotation");

        return takes;
}

/* Is "type" that of a pointer to an isl_* structure?
 */
bool generator::is_isl_type(QualType type)
{
        if (type->isPointerType()) {
                string s;

                type = type->getPointeeType();
                if (type->isFunctionType())
                        return false;
                s = type.getAsString();
                return s.substr(0, 4) == "isl_";
        }

        return false;
}

/* Is "type" one of the integral types with a negative value
 * indicating an error condition?
 */
bool generator::is_isl_neg_error(QualType type)
{
        return is_isl_bool(type) || is_isl_stat(type) || is_isl_size(type);
}

/* Is "type" the primitive type with the given name?
 */
static bool is_isl_primitive(QualType type, const char *name)
{
        string s;

        if (type->isPointerType())
                return false;

        s = type.getAsString();
        return s == name;
}

/* Is "type" the type isl_bool?
 */
bool generator::is_isl_bool(QualType type)
{
        return is_isl_primitive(type, "isl_bool");
}

/* Is "type" the type isl_stat?
 */
bool generator::is_isl_stat(QualType type)
{
        return is_isl_primitive(type, "isl_stat");
}

/* Is "type" the type isl_size?
 */
bool generator::is_isl_size(QualType type)
{
        return is_isl_primitive(type, "isl_size");
}

/* Is "type" that of a pointer to a function?
 */
bool generator::is_callback(QualType type)
{
        if (!type->isPointerType())
                return false;
        type = type->getPointeeType();
        return type->isFunctionType();
}

/* Is the parameter at position "i" of "fd" a pointer to a function?
 */
bool generator::is_callback_arg(FunctionDecl *fd, int i)
{
        ParmVarDecl *param = fd->getParamDecl(i);
        QualType type = param->getOriginalType();

        return is_callback(type);
}

/* Is "type" that of "char *" of "const char *"?
 */
bool generator::is_string(QualType type)
{
        if (type->isPointerType()) {
                string s = type->getPointeeType().getAsString();
                return s == "const char" || s == "char";
        }

        return false;
}

/* Is "type" that of "long"?
 */
bool generator::is_long(QualType type)
{
        const BuiltinType *builtin = type->getAs<BuiltinType>();
        return builtin && builtin->getKind() == BuiltinType::Long;
}

/* Is "type" that of "unsigned int"?
 */
static bool is_unsigned_int(QualType type)
{
        const BuiltinType *builtin = type->getAs<BuiltinType>();
        return builtin && builtin->getKind() == BuiltinType::UInt;
}

/* Return the name of the type that "type" points to.
 * The input "type" is assumed to be a pointer type.
 */
string generator::extract_type(QualType type)
{
        if (type->isPointerType())
                return type->getPointeeType().getAsString();
        die("Cannot extract type from non-pointer type");
}

/* Given the type of a function pointer, return the corresponding
 * function prototype.
 */
const FunctionProtoType *generator::extract_prototype(QualType type)
{
        return type->getPointeeType()->getAs<FunctionProtoType>();
}

/* Given the type of a function pointer, return the number of arguments
 * of the corresponding function prototype.
 */
int generator::prototype_n_args(QualType type)
{
        return extract_prototype(type)->getNumArgs();
}

/* Return the function name suffix for the type of "param".
 *
 * If the type of "param" is an isl object type,
 * then the suffix is the name of the type with the "isl" prefix removed,
 * but keeping the "_".
 * If the type is an unsigned integer, then the type suffix is "_ui".
 */
static std::string type_suffix(ParmVarDecl *param)
{
        QualType type;

        type = param->getOriginalType();
        if (generator::is_isl_type(type))
                return generator::extract_type(type).substr(3);
        else if (is_unsigned_int(type))
                return "_ui";
        generator::die("Unsupported type suffix");
}

/* If "suffix" is a suffix of "s", then return "s" with the suffix removed.
 * Otherwise, simply return "s".
 */
std::string generator::drop_suffix(const std::string &s,
        const std::string &suffix)
{
        size_t len, suffix_len;

        len = s.length();
        suffix_len = suffix.length();

        if (len >= suffix_len && s.substr(len - suffix_len) == suffix)
                return s.substr(0, len - suffix_len);
        else
                return s;
}

/* If "method" is overloaded, then return its name with the suffixes
 * corresponding to the types of the final arguments removed.
 * Otherwise, simply return the name of the function.
 * Start from the final argument and keep removing suffixes
 * matching arguments, independently of whether previously considered
 * arguments matched.
 */
string isl_class::name_without_type_suffixes(FunctionDecl *method)
{
        int num_params;
        string name;

        name = method->getName().str();
        if (!generator::is_overload(method))
                return name;

        num_params = method->getNumParams();
        for (int i = num_params - 1; i >= 0; --i) {
                ParmVarDecl *param;
                string type;

                param = method->getParamDecl(i);
                type = type_suffix(param);

                name = generator::drop_suffix(name, type);
        }

        return name;
}

/* Is function "fd" with the given name a "get" method?
 *
 * A "get" method is an instance method
 * with a name that starts with the get method prefix.
 */
bool isl_class::is_get_method_name(FunctionDecl *fd, const string &name) const
{
        return !is_static(fd) && prefixcmp(name.c_str(), get_prefix) == 0;
}

/* Extract the method name corresponding to "fd".
 *
 * If "fd" is a "get" method, then drop the "get" method prefix.
 */
string isl_class::method_name(FunctionDecl *fd) const
{
      string base = base_method_name(fd);

      if (is_get_method_name(fd, base))
              return base.substr(strlen(get_prefix));
      return base;
}