PetScan::extract_argument: extract out extract_addr_of_arg

[pet.git] / pet.cc

/*
 * Copyright 2011      Leiden University. All rights reserved.
 * Copyright 2012-2014 Ecole Normale Superieure. 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 LEIDEN UNIVERSITY ''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 LEIDEN UNIVERSITY 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
 * Leiden University.
 */ 

#include "config.h"

#include <stdlib.h>
#include <map>
#include <vector>
#include <iostream>
#ifdef HAVE_ADT_OWNINGPTR_H
#include <llvm/ADT/OwningPtr.h>
#else
#include <memory>
#endif
#include <llvm/Support/raw_ostream.h>
#include <llvm/Support/ManagedStatic.h>
#include <llvm/Support/Host.h>
#include <clang/Basic/Version.h>
#include <clang/Basic/FileSystemOptions.h>
#include <clang/Basic/FileManager.h>
#include <clang/Basic/TargetOptions.h>
#include <clang/Basic/TargetInfo.h>
#include <clang/Driver/Compilation.h>
#include <clang/Driver/Driver.h>
#include <clang/Driver/Tool.h>
#include <clang/Frontend/CompilerInstance.h>
#include <clang/Frontend/CompilerInvocation.h>
#ifdef HAVE_BASIC_DIAGNOSTICOPTIONS_H
#include <clang/Basic/DiagnosticOptions.h>
#else
#include <clang/Frontend/DiagnosticOptions.h>
#endif
#include <clang/Frontend/TextDiagnosticPrinter.h>
#ifdef HAVE_LEX_HEADERSEARCHOPTIONS_H
#include <clang/Lex/HeaderSearchOptions.h>
#else
#include <clang/Frontend/HeaderSearchOptions.h>
#endif
#include <clang/Frontend/LangStandard.h>
#ifdef HAVE_LEX_PREPROCESSOROPTIONS_H
#include <clang/Lex/PreprocessorOptions.h>
#else
#include <clang/Frontend/PreprocessorOptions.h>
#endif
#include <clang/Frontend/FrontendOptions.h>
#include <clang/Frontend/Utils.h>
#include <clang/Lex/HeaderSearch.h>
#include <clang/Lex/Preprocessor.h>
#include <clang/Lex/Pragma.h>
#include <clang/AST/ASTContext.h>
#include <clang/AST/ASTConsumer.h>
#include <clang/Sema/Sema.h>
#include <clang/Sema/SemaDiagnostic.h>
#include <clang/Parse/Parser.h>
#include <clang/Parse/ParseAST.h>

#include <isl/ctx.h>
#include <isl/constraint.h>

#include <pet.h>

#include "id.h"
#include "options.h"
#include "scan.h"
#include "print.h"

#define ARRAY_SIZE(array) (sizeof(array)/sizeof(*array))

using namespace std;
using namespace clang;
using namespace clang::driver;

#ifdef HAVE_ADT_OWNINGPTR_H
#define unique_ptr      llvm::OwningPtr
#endif

/* Called if we found something we didn't expect in one of the pragmas.
 * We'll provide more informative warnings later.
 */
static void unsupported(Preprocessor &PP, SourceLocation loc)
{
        DiagnosticsEngine &diag = PP.getDiagnostics();
        unsigned id = diag.getCustomDiagID(DiagnosticsEngine::Warning,
                                           "unsupported");
        DiagnosticBuilder B = diag.Report(loc, id);
}

static int get_int(const char *s)
{
        return s[0] == '"' ? atoi(s + 1) : atoi(s);
}

static ValueDecl *get_value_decl(Sema &sema, Token &token)
{
        IdentifierInfo *name;
        Decl *decl;

        if (token.isNot(tok::identifier))
                return NULL;

        name = token.getIdentifierInfo();
        decl = sema.LookupSingleName(sema.TUScope, name,
                                token.getLocation(), Sema::LookupOrdinaryName);
        return decl ? cast_or_null<ValueDecl>(decl) : NULL;
}

/* Handle pragmas of the form
 *
 *      #pragma value_bounds identifier lower_bound upper_bound
 *
 * For each such pragma, add a mapping
 *      { identifier[] -> [i] : lower_bound <= i <= upper_bound }
 * to value_bounds.
 */
struct PragmaValueBoundsHandler : public PragmaHandler {
        Sema &sema;
        isl_ctx *ctx;
        isl_union_map *value_bounds;

        PragmaValueBoundsHandler(isl_ctx *ctx, Sema &sema) :
            PragmaHandler("value_bounds"), ctx(ctx), sema(sema) {
                isl_space *space = isl_space_params_alloc(ctx, 0);
                value_bounds = isl_union_map_empty(space);
        }

        ~PragmaValueBoundsHandler() {
                isl_union_map_free(value_bounds);
        }

        virtual void HandlePragma(Preprocessor &PP,
                                  PragmaIntroducerKind Introducer,
                                  Token &ScopTok) {
                isl_id *id;
                isl_space *dim;
                isl_map *map;
                ValueDecl *vd;
                Token token;
                int lb;
                int ub;

                PP.Lex(token);
                vd = get_value_decl(sema, token);
                if (!vd) {
                        unsupported(PP, token.getLocation());
                        return;
                }

                PP.Lex(token);
                if (!token.isLiteral()) {
                        unsupported(PP, token.getLocation());
                        return;
                }

                lb = get_int(token.getLiteralData());

                PP.Lex(token);
                if (!token.isLiteral()) {
                        unsupported(PP, token.getLocation());
                        return;
                }

                ub = get_int(token.getLiteralData());

                dim = isl_space_alloc(ctx, 0, 0, 1);
                map = isl_map_universe(dim);
                map = isl_map_lower_bound_si(map, isl_dim_out, 0, lb);
                map = isl_map_upper_bound_si(map, isl_dim_out, 0, ub);
                id = isl_id_alloc(ctx, vd->getName().str().c_str(), vd);
                map = isl_map_set_tuple_id(map, isl_dim_in, id);

                value_bounds = isl_union_map_add_map(value_bounds, map);
        }
};

/* Given a variable declaration, check if it has an integer initializer
 * and if so, add a parameter corresponding to the variable to "value"
 * with its value fixed to the integer initializer and return the result.
 */
static __isl_give isl_set *extract_initialization(__isl_take isl_set *value,
        ValueDecl *decl)
{
        VarDecl *vd;
        Expr *expr;
        IntegerLiteral *il;
        isl_val *v;
        isl_ctx *ctx;
        isl_id *id;
        isl_space *space;
        isl_set *set;

        vd = cast<VarDecl>(decl);
        if (!vd)
                return value;
        if (!vd->getType()->isIntegerType())
                return value;
        expr = vd->getInit();
        if (!expr)
                return value;
        il = cast<IntegerLiteral>(expr);
        if (!il)
                return value;

        ctx = isl_set_get_ctx(value);
        id = isl_id_alloc(ctx, vd->getName().str().c_str(), vd);
        space = isl_space_params_alloc(ctx, 1);
        space = isl_space_set_dim_id(space, isl_dim_param, 0, id);
        set = isl_set_universe(space);

        v = PetScan::extract_int(ctx, il);
        set = isl_set_fix_val(set, isl_dim_param, 0, v);

        return isl_set_intersect(value, set);
}

/* Handle pragmas of the form
 *
 *      #pragma parameter identifier lower_bound
 * and
 *      #pragma parameter identifier lower_bound upper_bound
 *
 * For each such pragma, intersect the context with the set
 * [identifier] -> { [] : lower_bound <= identifier <= upper_bound }
 */
struct PragmaParameterHandler : public PragmaHandler {
        Sema &sema;
        isl_set *&context;
        isl_set *&context_value;

        PragmaParameterHandler(Sema &sema, isl_set *&context,
                isl_set *&context_value) :
                PragmaHandler("parameter"), sema(sema), context(context),
                context_value(context_value) {}

        virtual void HandlePragma(Preprocessor &PP,
                                  PragmaIntroducerKind Introducer,
                                  Token &ScopTok) {
                isl_id *id;
                isl_ctx *ctx = isl_set_get_ctx(context);
                isl_space *dim;
                isl_set *set;
                ValueDecl *vd;
                Token token;
                int lb;
                int ub;
                bool has_ub = false;

                PP.Lex(token);
                vd = get_value_decl(sema, token);
                if (!vd) {
                        unsupported(PP, token.getLocation());
                        return;
                }

                PP.Lex(token);
                if (!token.isLiteral()) {
                        unsupported(PP, token.getLocation());
                        return;
                }

                lb = get_int(token.getLiteralData());

                PP.Lex(token);
                if (token.isLiteral()) {
                        has_ub = true;
                        ub = get_int(token.getLiteralData());
                } else if (token.isNot(tok::eod)) {
                        unsupported(PP, token.getLocation());
                        return;
                }

                id = isl_id_alloc(ctx, vd->getName().str().c_str(), vd);
                dim = isl_space_params_alloc(ctx, 1);
                dim = isl_space_set_dim_id(dim, isl_dim_param, 0, id);

                set = isl_set_universe(dim);

                set = isl_set_lower_bound_si(set, isl_dim_param, 0, lb);
                if (has_ub)
                        set = isl_set_upper_bound_si(set, isl_dim_param, 0, ub);

                context = isl_set_intersect(context, set);

                context_value = extract_initialization(context_value, vd);
        }
};

/* Handle pragmas of the form
 *
 *      #pragma pencil independent
 *
 * For each such pragma, add an entry to the "independent" vector.
 */
struct PragmaPencilHandler : public PragmaHandler {
        std::vector<Independent> &independent;

        PragmaPencilHandler(std::vector<Independent> &independent) :
                PragmaHandler("pencil"), independent(independent) {}

        virtual void HandlePragma(Preprocessor &PP,
                                  PragmaIntroducerKind Introducer,
                                  Token &PencilTok) {
                Token token;
                IdentifierInfo *info;

                PP.Lex(token);
                if (token.isNot(tok::identifier))
                        return;

                info = token.getIdentifierInfo();
                if (!info->isStr("independent"))
                        return;

                PP.Lex(token);
                if (token.isNot(tok::eod))
                        return;

                SourceManager &SM = PP.getSourceManager();
                SourceLocation sloc = PencilTok.getLocation();
                unsigned line = SM.getExpansionLineNumber(sloc);
                independent.push_back(Independent(line));
        }
};

#ifdef HAVE_TRANSLATELINECOL

/* Return a SourceLocation for line "line", column "col" of file "FID".
 */
SourceLocation translateLineCol(SourceManager &SM, FileID FID, unsigned line,
        unsigned col)
{
        return SM.translateLineCol(FID, line, col);
}

#else

/* Return a SourceLocation for line "line", column "col" of file "FID".
 */
SourceLocation translateLineCol(SourceManager &SM, FileID FID, unsigned line,
        unsigned col)
{
        return SM.getLocation(SM.getFileEntryForID(FID), line, col);
}

#endif

/* List of pairs of #pragma scop and #pragma endscop locations.
 */
struct ScopLocList {
        std::vector<ScopLoc> list;

        /* Add a new start (#pragma scop) location to the list.
         * If the last #pragma scop did not have a matching
         * #pragma endscop then overwrite it.
         */
        void add_start(unsigned line, unsigned start) {
                ScopLoc loc;

                loc.start_line = line;
                loc.start = start;
                if (list.size() == 0 || list[list.size() - 1].end != 0)
                        list.push_back(loc);
                else
                        list[list.size() - 1] = loc;
        }

        /* Set the end location (#pragma endscop) of the last pair
         * in the list.
         * If there is no such pair of if the end of that pair
         * is already set, then ignore the spurious #pragma endscop.
         */
        void add_end(unsigned end) {
                if (list.size() == 0 || list[list.size() - 1].end != 0)
                        return;
                list[list.size() - 1].end = end;
        }
};

/* Handle pragmas of the form
 *
 *      #pragma scop
 *
 * In particular, store the location of the line containing
 * the pragma in the list "scops".
 */
struct PragmaScopHandler : public PragmaHandler {
        ScopLocList &scops;

        PragmaScopHandler(ScopLocList &scops) :
                PragmaHandler("scop"), scops(scops) {}

        virtual void HandlePragma(Preprocessor &PP,
                                  PragmaIntroducerKind Introducer,
                                  Token &ScopTok) {
                SourceManager &SM = PP.getSourceManager();
                SourceLocation sloc = ScopTok.getLocation();
                int line = SM.getExpansionLineNumber(sloc);
                sloc = translateLineCol(SM, SM.getFileID(sloc), line, 1);
                scops.add_start(line, SM.getFileOffset(sloc));
        }
};

/* Handle pragmas of the form
 *
 *      #pragma endscop
 *
 * In particular, store the location of the line following the one containing
 * the pragma in the list "scops".
 */
struct PragmaEndScopHandler : public PragmaHandler {
        ScopLocList &scops;

        PragmaEndScopHandler(ScopLocList &scops) :
                PragmaHandler("endscop"), scops(scops) {}

        virtual void HandlePragma(Preprocessor &PP,
                                  PragmaIntroducerKind Introducer,
                                  Token &EndScopTok) {
                SourceManager &SM = PP.getSourceManager();
                SourceLocation sloc = EndScopTok.getLocation();
                int line = SM.getExpansionLineNumber(sloc);
                sloc = translateLineCol(SM, SM.getFileID(sloc), line + 1, 1);
                scops.add_end(SM.getFileOffset(sloc));
        }
};

/* Handle pragmas of the form
 *
 *      #pragma live-out identifier, identifier, ...
 *
 * Each identifier on the line is stored in live_out.
 */
struct PragmaLiveOutHandler : public PragmaHandler {
        Sema &sema;
        set<ValueDecl *> &live_out;

        PragmaLiveOutHandler(Sema &sema, set<ValueDecl *> &live_out) :
                PragmaHandler("live"), sema(sema), live_out(live_out) {}

        virtual void HandlePragma(Preprocessor &PP,
                                  PragmaIntroducerKind Introducer,
                                  Token &ScopTok) {
                Token token;

                PP.Lex(token);
                if (token.isNot(tok::minus))
                        return;
                PP.Lex(token);
                if (token.isNot(tok::identifier) ||
                    !token.getIdentifierInfo()->isStr("out"))
                        return;

                PP.Lex(token);
                while (token.isNot(tok::eod)) {
                        ValueDecl *vd;

                        vd = get_value_decl(sema, token);
                        if (!vd) {
                                unsupported(PP, token.getLocation());
                                return;
                        }
                        live_out.insert(vd);
                        PP.Lex(token);
                        if (token.is(tok::comma))
                                PP.Lex(token);
                }
        }
};

/* For each array in "scop", set its value_bounds property
 * based on the information in "value_bounds" and
 * mark it as live_out if it appears in "live_out".
 */
static void update_arrays(struct pet_scop *scop,
        __isl_take isl_union_map *value_bounds, set<ValueDecl *> &live_out)
{
        set<ValueDecl *>::iterator lo_it;
        isl_ctx *ctx = isl_union_map_get_ctx(value_bounds);

        if (!scop) {
                isl_union_map_free(value_bounds);
                return;
        }

        for (int i = 0; i < scop->n_array; ++i) {
                isl_id *id;
                isl_space *space;
                isl_map *bounds;
                ValueDecl *decl;
                pet_array *array = scop->arrays[i];

                id = isl_set_get_tuple_id(array->extent);
                decl = pet_id_get_decl(id);

                space = isl_space_alloc(ctx, 0, 0, 1);
                space = isl_space_set_tuple_id(space, isl_dim_in, id);

                bounds = isl_union_map_extract_map(value_bounds, space);
                if (!isl_map_plain_is_empty(bounds))
                        array->value_bounds = isl_map_range(bounds);
                else
                        isl_map_free(bounds);

                lo_it = live_out.find(decl);
                if (lo_it != live_out.end())
                        array->live_out = 1;
        }

        isl_union_map_free(value_bounds);
}

/* Extract a pet_scop (if any) from each appropriate function.
 * Each detected scop is passed to "fn".
 * When autodetecting, at most one scop is extracted from each function.
 * If "function" is not NULL, then we only extract a pet_scop if the
 * name of the function matches.
 * If "autodetect" is false, then we only extract if we have seen
 * scop and endscop pragmas and if these are situated inside the function
 * body.
 */
struct PetASTConsumer : public ASTConsumer {
        Preprocessor &PP;
        ASTContext &ast_context;
        DiagnosticsEngine &diags;
        ScopLocList &scops;
        std::vector<Independent> independent;
        const char *function;
        pet_options *options;
        isl_ctx *ctx;
        isl_set *context;
        isl_set *context_value;
        set<ValueDecl *> live_out;
        PragmaValueBoundsHandler *vb_handler;
        int (*fn)(struct pet_scop *scop, void *user);
        void *user;
        bool error;

        PetASTConsumer(isl_ctx *ctx, Preprocessor &PP, ASTContext &ast_context,
                DiagnosticsEngine &diags, ScopLocList &scops,
                const char *function, pet_options *options,
                int (*fn)(struct pet_scop *scop, void *user), void *user) :
                ctx(ctx), PP(PP), ast_context(ast_context), diags(diags),
                scops(scops), function(function), options(options),
                vb_handler(NULL), fn(fn), user(user), error(false)
        {
                isl_space *space;
                space = isl_space_params_alloc(ctx, 0);
                context = isl_set_universe(isl_space_copy(space));
                context_value = isl_set_universe(space);
        }

        ~PetASTConsumer() {
                isl_set_free(context);
                isl_set_free(context_value);
        }

        void handle_value_bounds(Sema *sema) {
                vb_handler = new PragmaValueBoundsHandler(ctx, *sema);
                PP.AddPragmaHandler(vb_handler);
        }

        /* Add all pragma handlers to this->PP.
         * The pencil pragmas are only handled if the pencil option is set.
         */
        void add_pragma_handlers(Sema *sema) {
                PP.AddPragmaHandler(new PragmaParameterHandler(*sema, context,
                                                                context_value));
                if (options->pencil) {
                        PragmaHandler *PH;
                        PH = new PragmaPencilHandler(independent);
                        PP.AddPragmaHandler(PH);
                }
                handle_value_bounds(sema);
        }

        __isl_give isl_union_map *get_value_bounds() {
                return isl_union_map_copy(vb_handler->value_bounds);
        }

        /* Pass "scop" to "fn" after performing some postprocessing.
         * In particular, add the context and value_bounds constraints
         * speficied through pragmas, add reference identifiers and
         * reset user pointers on parameters and tuple ids.
         *
         * If "scop" does not contain any statements and autodetect
         * is turned on, then skip it.
         */
        void call_fn(pet_scop *scop) {
                if (!scop)
                        return;
                if (diags.hasErrorOccurred()) {
                        pet_scop_free(scop);
                        return;
                }
                if (options->autodetect && scop->n_stmt == 0) {
                        pet_scop_free(scop);
                        return;
                }
                scop->context = isl_set_intersect(scop->context,
                                                isl_set_copy(context));
                scop->context_value = isl_set_intersect(scop->context_value,
                                                isl_set_copy(context_value));

                update_arrays(scop, get_value_bounds(), live_out);

                scop = pet_scop_add_ref_ids(scop);
                scop = pet_scop_anonymize(scop);

                if (fn(scop, user) < 0)
                        error = true;
        }

        /* For each explicitly marked scop (using pragmas),
         * extract the scop and call "fn" on it if it is inside "fd".
         */
        void scan_scops(FunctionDecl *fd) {
                unsigned start, end;
                vector<ScopLoc>::iterator it;
                isl_union_map *vb = vb_handler->value_bounds;
                SourceManager &SM = PP.getSourceManager();
                pet_scop *scop;

                if (scops.list.size() == 0)
                        return;

                start = SM.getFileOffset(fd->getLocStart());
                end = SM.getFileOffset(fd->getLocEnd());

                for (it = scops.list.begin(); it != scops.list.end(); ++it) {
                        ScopLoc loc = *it;
                        if (!loc.end)
                                continue;
                        if (start > loc.end)
                                continue;
                        if (end < loc.start)
                                continue;
                        PetScan ps(PP, ast_context, fd, loc, options,
                                    isl_union_map_copy(vb), independent);
                        scop = ps.scan(fd);
                        call_fn(scop);
                }
        }

        virtual HandleTopLevelDeclReturn HandleTopLevelDecl(DeclGroupRef dg) {
                DeclGroupRef::iterator it;

                if (error)
                        return HandleTopLevelDeclContinue;

                for (it = dg.begin(); it != dg.end(); ++it) {
                        isl_union_map *vb = vb_handler->value_bounds;
                        FunctionDecl *fd = dyn_cast<clang::FunctionDecl>(*it);
                        if (!fd)
                                continue;
                        if (!fd->hasBody())
                                continue;
                        if (function &&
                            fd->getNameInfo().getAsString() != function)
                                continue;
                        if (options->autodetect) {
                                ScopLoc loc;
                                pet_scop *scop;
                                PetScan ps(PP, ast_context, fd, loc, options,
                                            isl_union_map_copy(vb),
                                            independent);
                                scop = ps.scan(fd);
                                call_fn(scop);
                                continue;
                        }
                        scan_scops(fd);
                }

                return HandleTopLevelDeclContinue;
        }
};

static const char *ResourceDir =
        CLANG_PREFIX "/lib/clang/" CLANG_VERSION_STRING;

static const char *implicit_functions[] = {
        "min", "max", "intMod", "intCeil", "intFloor", "ceild", "floord"
};
static const char *pencil_implicit_functions[] = {
        "imin", "umin", "imax", "umax", "__pencil_kill"
};

/* Should "ident" be treated as an implicit function?
 * If "pencil" is set, then also allow pencil specific builtins.
 */
static bool is_implicit(const IdentifierInfo *ident, int pencil)
{
        const char *name = ident->getNameStart();
        for (int i = 0; i < ARRAY_SIZE(implicit_functions); ++i)
                if (!strcmp(name, implicit_functions[i]))
                        return true;
        if (!pencil)
                return false;
        for (int i = 0; i < ARRAY_SIZE(pencil_implicit_functions); ++i)
                if (!strcmp(name, pencil_implicit_functions[i]))
                        return true;
        return false;
}

/* Ignore implicit function declaration warnings on
 * "min", "max", "ceild" and "floord" as we detect and handle these
 * in PetScan.
 * If "pencil" is set, then also ignore them on pencil specific
 * builtins.
 */
struct MyDiagnosticPrinter : public TextDiagnosticPrinter {
        const DiagnosticOptions *DiagOpts;
        int pencil;
#ifdef HAVE_BASIC_DIAGNOSTICOPTIONS_H
        MyDiagnosticPrinter(DiagnosticOptions *DO, int pencil) :
                TextDiagnosticPrinter(llvm::errs(), DO), pencil(pencil) {}
        virtual DiagnosticConsumer *clone(DiagnosticsEngine &Diags) const {
                return new MyDiagnosticPrinter(&Diags.getDiagnosticOptions(),
                                                pencil);
        }
#else
        MyDiagnosticPrinter(const DiagnosticOptions &DO, int pencil) :
                DiagOpts(&DO), TextDiagnosticPrinter(llvm::errs(), DO),
                pencil(pencil) {}
        virtual DiagnosticConsumer *clone(DiagnosticsEngine &Diags) const {
                return new MyDiagnosticPrinter(*DiagOpts, pencil);
        }
#endif
        virtual void HandleDiagnostic(DiagnosticsEngine::Level level,
                                        const DiagnosticInfo &info) {
                if (info.getID() == diag::ext_implicit_function_decl &&
                    info.getNumArgs() == 1 &&
                    info.getArgKind(0) == DiagnosticsEngine::ak_identifierinfo &&
                    is_implicit(info.getArgIdentifier(0), pencil))
                        /* ignore warning */;
                else
                        TextDiagnosticPrinter::HandleDiagnostic(level, info);
        }
};

#ifdef USE_ARRAYREF

#ifdef HAVE_CXXISPRODUCTION
static Driver *construct_driver(const char *binary, DiagnosticsEngine &Diags)
{
        return new Driver(binary, llvm::sys::getDefaultTargetTriple(),
                            "", false, false, Diags);
}
#elif defined(HAVE_ISPRODUCTION)
static Driver *construct_driver(const char *binary, DiagnosticsEngine &Diags)
{
        return new Driver(binary, llvm::sys::getDefaultTargetTriple(),
                            "", false, Diags);
}
#elif defined(DRIVER_CTOR_TAKES_DEFAULTIMAGENAME)
static Driver *construct_driver(const char *binary, DiagnosticsEngine &Diags)
{
        return new Driver(binary, llvm::sys::getDefaultTargetTriple(),
                            "", Diags);
}
#else
static Driver *construct_driver(const char *binary, DiagnosticsEngine &Diags)
{
        return new Driver(binary, llvm::sys::getDefaultTargetTriple(), Diags);
}
#endif

namespace clang { namespace driver { class Job; } }

/* Clang changed its API from 3.5 to 3.6 and once more in 3.7.
 * We fix this with a simple overloaded function here.
 */
struct ClangAPI {
        static Job *command(Job *J) { return J; }
        static Job *command(Job &J) { return &J; }
        static Command *command(Command &C) { return &C; }
};

/* Create a CompilerInvocation object that stores the command line
 * arguments constructed by the driver.
 * The arguments are mainly useful for setting up the system include
 * paths on newer clangs and on some platforms.
 */
static CompilerInvocation *construct_invocation(const char *filename,
        DiagnosticsEngine &Diags)
{
        const char *binary = CLANG_PREFIX"/bin/clang";
        const unique_ptr<Driver> driver(construct_driver(binary, Diags));
        std::vector<const char *> Argv;
        Argv.push_back(binary);
        Argv.push_back(filename);
        const unique_ptr<Compilation> compilation(
                driver->BuildCompilation(llvm::ArrayRef<const char *>(Argv)));
        JobList &Jobs = compilation->getJobs();
        if (Jobs.size() < 1)
                return NULL;

        Command *cmd = cast<Command>(ClangAPI::command(*Jobs.begin()));
        if (strcmp(cmd->getCreator().getName(), "clang"))
                return NULL;

        const ArgStringList *args = &cmd->getArguments();

        CompilerInvocation *invocation = new CompilerInvocation;
        CompilerInvocation::CreateFromArgs(*invocation, args->data() + 1,
                                                args->data() + args->size(),
                                                Diags);
        return invocation;
}

#else

static CompilerInvocation *construct_invocation(const char *filename,
        DiagnosticsEngine &Diags)
{
        return NULL;
}

#endif

#ifdef HAVE_BASIC_DIAGNOSTICOPTIONS_H

static MyDiagnosticPrinter *construct_printer(CompilerInstance *Clang,
        int pencil)
{
        return new MyDiagnosticPrinter(new DiagnosticOptions(), pencil);
}

#else

static MyDiagnosticPrinter *construct_printer(CompilerInstance *Clang,
        int pencil)
{
        return new MyDiagnosticPrinter(Clang->getDiagnosticOpts(), pencil);
}

#endif

#ifdef CREATETARGETINFO_TAKES_SHARED_PTR

static TargetInfo *create_target_info(CompilerInstance *Clang,
        DiagnosticsEngine &Diags)
{
        shared_ptr<TargetOptions> TO = Clang->getInvocation().TargetOpts;
        TO->Triple = llvm::sys::getDefaultTargetTriple();
        return TargetInfo::CreateTargetInfo(Diags, TO);
}

#elif defined(CREATETARGETINFO_TAKES_POINTER)

static TargetInfo *create_target_info(CompilerInstance *Clang,
        DiagnosticsEngine &Diags)
{
        TargetOptions &TO = Clang->getTargetOpts();
        TO.Triple = llvm::sys::getDefaultTargetTriple();
        return TargetInfo::CreateTargetInfo(Diags, &TO);
}

#else

static TargetInfo *create_target_info(CompilerInstance *Clang,
        DiagnosticsEngine &Diags)
{
        TargetOptions &TO = Clang->getTargetOpts();
        TO.Triple = llvm::sys::getDefaultTargetTriple();
        return TargetInfo::CreateTargetInfo(Diags, TO);
}

#endif

#ifdef CREATEDIAGNOSTICS_TAKES_ARG

static void create_diagnostics(CompilerInstance *Clang)
{
        Clang->createDiagnostics(0, NULL);
}

#else

static void create_diagnostics(CompilerInstance *Clang)
{
        Clang->createDiagnostics();
}

#endif

#ifdef CREATEPREPROCESSOR_TAKES_TUKIND

static void create_preprocessor(CompilerInstance *Clang)
{
        Clang->createPreprocessor(TU_Complete);
}

#else

static void create_preprocessor(CompilerInstance *Clang)
{
        Clang->createPreprocessor();
}

#endif

#ifdef ADDPATH_TAKES_4_ARGUMENTS

void add_path(HeaderSearchOptions &HSO, string Path)
{
        HSO.AddPath(Path, frontend::Angled, false, false);
}

#else

void add_path(HeaderSearchOptions &HSO, string Path)
{
        HSO.AddPath(Path, frontend::Angled, true, false, false);
}

#endif

#ifdef HAVE_SETMAINFILEID

static void create_main_file_id(SourceManager &SM, const FileEntry *file)
{
        SM.setMainFileID(SM.createFileID(file, SourceLocation(),
                                        SrcMgr::C_User));
}

#else

static void create_main_file_id(SourceManager &SM, const FileEntry *file)
{
        SM.createMainFileID(file);
}

#endif

/* Add pet specific predefines to the preprocessor.
 * Currently, these are all pencil specific, so they are only
 * added if "pencil" is set.
 *
 * We mimic the way <command line> is handled inside clang.
 */
void add_predefines(Preprocessor &PP, int pencil)
{
        string s;

        if (!pencil)
                return;

        s = PP.getPredefines();
        s += "# 1 \"<pet>\" 1\n"
             "void __pencil_assume(int assumption);\n"
             "#define pencil_access(f) annotate(\"pencil_access(\" #f \")\")\n"
             "# 1 \"<built-in>\" 2\n";
        PP.setPredefines(s);
}

/* Extract a pet_scop from each function in the C source file called "filename".
 * Each detected scop is passed to "fn".
 * If "function" is not NULL, only extract a pet_scop from the function
 * with that name.
 * If "autodetect" is set, extract any pet_scop we can find.
 * Otherwise, extract the pet_scop from the region delimited
 * by "scop" and "endscop" pragmas.
 *
 * We first set up the clang parser and then try to extract the
 * pet_scop from the appropriate function(s) in PetASTConsumer.
 */
static int foreach_scop_in_C_source(isl_ctx *ctx,
        const char *filename, const char *function, pet_options *options,
        int (*fn)(struct pet_scop *scop, void *user), void *user)
{
        CompilerInstance *Clang = new CompilerInstance();
        create_diagnostics(Clang);
        DiagnosticsEngine &Diags = Clang->getDiagnostics();
        Diags.setSuppressSystemWarnings(true);
        CompilerInvocation *invocation = construct_invocation(filename, Diags);
        if (invocation)
                Clang->setInvocation(invocation);
        Diags.setClient(construct_printer(Clang, options->pencil));
        Clang->createFileManager();
        Clang->createSourceManager(Clang->getFileManager());
        TargetInfo *target = create_target_info(Clang, Diags);
        Clang->setTarget(target);
        CompilerInvocation::setLangDefaults(Clang->getLangOpts(), IK_C,
                                            LangStandard::lang_unspecified);
        HeaderSearchOptions &HSO = Clang->getHeaderSearchOpts();
        HSO.ResourceDir = ResourceDir;
        for (int i = 0; i < options->n_path; ++i)
                add_path(HSO, options->paths[i]);
        PreprocessorOptions &PO = Clang->getPreprocessorOpts();
        for (int i = 0; i < options->n_define; ++i)
                PO.addMacroDef(options->defines[i]);
        create_preprocessor(Clang);
        Preprocessor &PP = Clang->getPreprocessor();
        add_predefines(PP, options->pencil);
        PP.getBuiltinInfo().InitializeBuiltins(PP.getIdentifierTable(),
                PP.getLangOpts());

        ScopLocList scops;

        const FileEntry *file = Clang->getFileManager().getFile(filename);
        if (!file)
                isl_die(ctx, isl_error_unknown, "unable to open file",
                        do { delete Clang; return -1; } while (0));
        create_main_file_id(Clang->getSourceManager(), file);

        Clang->createASTContext();
        PetASTConsumer consumer(ctx, PP, Clang->getASTContext(), Diags,
                                scops, function, options, fn, user);
        Sema *sema = new Sema(PP, Clang->getASTContext(), consumer);

        if (!options->autodetect) {
                PP.AddPragmaHandler(new PragmaScopHandler(scops));
                PP.AddPragmaHandler(new PragmaEndScopHandler(scops));
                PP.AddPragmaHandler(new PragmaLiveOutHandler(*sema,
                                                        consumer.live_out));
        }

        consumer.add_pragma_handlers(sema);

        Diags.getClient()->BeginSourceFile(Clang->getLangOpts(), &PP);
        ParseAST(*sema);
        Diags.getClient()->EndSourceFile();

        delete sema;
        delete Clang;

        return consumer.error ? -1 : 0;
}

/* Extract a pet_scop from each function in the C source file called "filename".
 * Each detected scop is passed to "fn".
 *
 * This wrapper around foreach_scop_in_C_source is mainly used to ensure
 * that all objects on the stack (of that function) are destroyed before we
 * call llvm_shutdown.
 */
static int pet_foreach_scop_in_C_source(isl_ctx *ctx,
        const char *filename, const char *function,
        int (*fn)(struct pet_scop *scop, void *user), void *user)
{
        int r;
        pet_options *options;
        bool allocated = false;

        options = isl_ctx_peek_pet_options(ctx);
        if (!options) {
                options = pet_options_new_with_defaults();
                allocated = true;
        }

        r = foreach_scop_in_C_source(ctx, filename, function, options,
                                        fn, user);
        llvm::llvm_shutdown();

        if (allocated)
                pet_options_free(options);

        return r;
}

/* Store "scop" into the address pointed to by "user".
 * Return -1 to indicate that we are not interested in any further scops.
 * This function should therefore not be called a second call
 * so in principle there is no need to check if we have already set *user.
 */
static int set_first_scop(pet_scop *scop, void *user)
{
        pet_scop **p = (pet_scop **) user;

        if (!*p)
                *p = scop;
        else
                pet_scop_free(scop);

        return -1;
}

/* Extract a pet_scop from the C source file called "filename".
 * If "function" is not NULL, extract the pet_scop from the function
 * with that name.
 *
 * We start extracting scops from every function and then abort
 * as soon as we have extracted one scop.
 */
struct pet_scop *pet_scop_extract_from_C_source(isl_ctx *ctx,
        const char *filename, const char *function)
{
        pet_scop *scop = NULL;

        pet_foreach_scop_in_C_source(ctx, filename, function,
                                        &set_first_scop, &scop);

        return scop;
}

/* Internal data structure for pet_transform_C_source
 *
 * transform is the function that should be called to print a scop
 * in is the input source file
 * out is the output source file
 * end is the offset of the end of the previous scop (zero if we have not
 *      found any scop yet)
 * p is a printer that prints to out.
 */
struct pet_transform_data {
        __isl_give isl_printer *(*transform)(__isl_take isl_printer *p,
                struct pet_scop *scop, void *user);
        void *user;

        FILE *in;
        FILE *out;
        unsigned end;
        isl_printer *p;
};

/* This function is called each time a scop is detected.
 *
 * We first copy the input text code from the end of the previous scop
 * until the start of "scop" and then print the scop itself through
 * a call to data->transform.  We set up the printer to print
 * the transformed code with the same (initial) indentation as
 * the original code.
 * Finally, we keep track of the end of "scop" so that we can
 * continue copying when we find the next scop.
 *
 * Before calling data->transform, we store a pointer to the original
 * input file in the extended scop in case the user wants to call
 * pet_scop_print_original from the callback.
 */
static int pet_transform(struct pet_scop *scop, void *user)
{
        struct pet_transform_data *data = (struct pet_transform_data *) user;
        unsigned start;

        start = pet_loc_get_start(scop->loc);
        if (copy(data->in, data->out, data->end, start) < 0)
                goto error;
        data->end = pet_loc_get_end(scop->loc);
        scop = pet_scop_set_input_file(scop, data->in);
        data->p = isl_printer_set_indent_prefix(data->p,
                                        pet_loc_get_indent(scop->loc));
        data->p = data->transform(data->p, scop, data->user);
        if (!data->p)
                return -1;
        return 0;
error:
        pet_scop_free(scop);
        return -1;
}

/* Transform the C source file "input" by rewriting each scop
 * through a call to "transform".
 * When autodetecting scops, at most one scop per function is rewritten.
 * The transformed C code is written to "output".
 *
 * For each scop we find, we first copy the input text code
 * from the end of the previous scop (or the beginning of the file
 * in case of the first scop) until the start of the scop
 * and then print the scop itself through a call to "transform".
 * At the end we copy everything from the end of the final scop
 * until the end of the input file to "output".
 */
int pet_transform_C_source(isl_ctx *ctx, const char *input, FILE *out,
        __isl_give isl_printer *(*transform)(__isl_take isl_printer *p,
                struct pet_scop *scop, void *user), void *user)
{
        struct pet_transform_data data;
        int r;

        data.in = stdin;
        data.out = out;
        if (input && strcmp(input, "-")) {
                data.in = fopen(input, "r");
                if (!data.in)
                        isl_die(ctx, isl_error_unknown, "unable to open file",
                                return -1);
        }

        data.p = isl_printer_to_file(ctx, data.out);
        data.p = isl_printer_set_output_format(data.p, ISL_FORMAT_C);

        data.transform = transform;
        data.user = user;
        data.end = 0;
        r = pet_foreach_scop_in_C_source(ctx, input, NULL,
                                        &pet_transform, &data);

        isl_printer_free(data.p);
        if (!data.p)
                r = -1;
        if (r == 0 && copy(data.in, data.out, data.end, -1) < 0)
                r = -1;

        if (data.in != stdin)
                fclose(data.in);

        return r;
}