From 401452e57ae897d3e5829ed12bfcccac82548e91 Mon Sep 17 00:00:00 2001 From: Eelco Dolstra Date: Mon, 21 Jul 2003 08:55:49 +0000 Subject: [PATCH] * Memoize the evaluation of Fix expressions to speed up computation. --- src/fix.cc | 62 ++++++++++++++++++++++++++++++++++++----------------- src/test.cc | 10 ++++----- 2 files changed, 47 insertions(+), 25 deletions(-) diff --git a/src/fix.cc b/src/fix.cc index cf6d5617a..6e3809f82 100644 --- a/src/fix.cc +++ b/src/fix.cc @@ -8,15 +8,24 @@ typedef ATerm Expr; +typedef map NormalForms; -static Strings searchDirs; +struct EvalState +{ + Strings searchDirs; + NormalForms normalForms; +}; -static string searchPath(string relPath) +static Expr evalFile(EvalState & state, string fileName); +static Expr evalExpr(EvalState & state, Expr e); + + +static string searchPath(const Strings & searchDirs, string relPath) { if (string(relPath, 0, 1) == "/") return relPath; - for (Strings::iterator i = searchDirs.begin(); + for (Strings::const_iterator i = searchDirs.begin(); i != searchDirs.end(); i++) { string path = *i + "/" + relPath; @@ -29,9 +38,6 @@ static string searchPath(string relPath) } -static Expr evalFile(string fileName); - - static Expr substExpr(string x, Expr rep, Expr e) { char * s; @@ -98,7 +104,7 @@ static Expr substExprMany(ATermList formals, ATermList args, Expr body) } -static Expr evalExpr(Expr e) +static Expr evalExpr2(EvalState & state, Expr e) { char * s1; Expr e1, e2, e3, e4; @@ -119,21 +125,22 @@ static Expr evalExpr(Expr e) /* Application. */ if (ATmatch(e, "App(, [])", &e1, &e2)) { - e1 = evalExpr(e1); + e1 = evalExpr(state, e1); if (!ATmatch(e1, "Function([], )", &e3, &e4)) throw badTerm("expecting a function", e1); - return evalExpr(substExprMany((ATermList) e3, (ATermList) e2, e4)); + return evalExpr(state, + substExprMany((ATermList) e3, (ATermList) e2, e4)); } /* Fix inclusion. */ if (ATmatch(e, "IncludeFix()", &s1)) { string fileName(s1); - return evalFile(s1); + return evalFile(state, s1); } /* Relative files. */ if (ATmatch(e, "Relative()", &s1)) { - string srcPath = searchPath(s1); + string srcPath = searchPath(state.searchDirs, s1); string dstPath; FSId id; addToStore(srcPath, dstPath, id, true); @@ -160,7 +167,7 @@ static Expr evalExpr(Expr e) ATerm bnd = ATgetFirst(bnds); if (!ATmatch(bnd, "(, )", &s1, &e1)) throw badTerm("binding expected", bnd); - bndMap[s1] = evalExpr(e1); + bndMap[s1] = evalExpr(state, e1); bnds = ATgetNext(bnds); } @@ -218,7 +225,7 @@ static Expr evalExpr(Expr e) /* BaseName primitive function. */ if (ATmatch(e, "BaseName()", &e1)) { - e1 = evalExpr(e1); + e1 = evalExpr(state, e1); if (!ATmatch(e1, "", &s1)) throw badTerm("string expected", e1); return ATmake("", baseNameOf(s1).c_str()); @@ -229,22 +236,37 @@ static Expr evalExpr(Expr e) } -static Expr evalFile(string relPath) +static Expr evalExpr(EvalState & state, Expr e) { - string path = searchPath(relPath); + /* Consult the memo table to quickly get the normal form of + previously evaluated expressions. */ + NormalForms::iterator i = state.normalForms.find(e); + if (i != state.normalForms.end()) return i->second; + + /* Otherwise, evaluate and memoize. */ + Expr nf = evalExpr2(state, e); + state.normalForms[e] = nf; + return nf; +} + + +static Expr evalFile(EvalState & state, string relPath) +{ + string path = searchPath(state.searchDirs, relPath); Expr e = ATreadFromNamedFile(path.c_str()); if (!e) throw Error(format("unable to read a term from `%1%'") % path); - return evalExpr(e); + return evalExpr(state, e); } void run(Strings args) { + EvalState state; Strings files; - searchDirs.push_back("."); - searchDirs.push_back(nixDataDir + "/fix"); + state.searchDirs.push_back("."); + state.searchDirs.push_back(nixDataDir + "/fix"); for (Strings::iterator it = args.begin(); it != args.end(); ) @@ -254,7 +276,7 @@ void run(Strings args) if (arg == "--includedir" || arg == "-I") { if (it == args.end()) throw UsageError(format("argument required in `%1%'") % arg); - searchDirs.push_back(*it++); + state.searchDirs.push_back(*it++); } else if (arg[0] == '-') throw UsageError(format("unknown flag `%1%`") % arg); @@ -267,7 +289,7 @@ void run(Strings args) for (Strings::iterator it = files.begin(); it != files.end(); it++) { - Expr e = evalFile(*it); + Expr e = evalFile(state, *it); char * s; if (ATmatch(e, "FSId()", &s)) { cout << format("%1%\n") % s; diff --git a/src/test.cc b/src/test.cc index 5c7559af6..6b567abe0 100644 --- a/src/test.cc +++ b/src/test.cc @@ -117,7 +117,7 @@ void runTests() ((string) builder1id).c_str(), builder1fn.c_str(), ((string) builder1id).c_str()); - FSId fs1id = writeTerm(fs1, "", 0); + FSId fs1id = writeTerm(fs1, ""); realise(fs1id); realise(fs1id); @@ -127,7 +127,7 @@ void runTests() ((string) builder1id).c_str(), (builder1fn + "_bla").c_str(), ((string) builder1id).c_str()); - FSId fs2id = writeTerm(fs2, "", 0); + FSId fs2id = writeTerm(fs2, ""); realise(fs2id); realise(fs2id); @@ -143,7 +143,7 @@ void runTests() thisSystem.c_str(), out1fn.c_str()); debug(printTerm(fs3)); - FSId fs3id = writeTerm(fs3, "", 0); + FSId fs3id = writeTerm(fs3, ""); realise(fs3id); realise(fs3id); @@ -158,7 +158,7 @@ void runTests() ((string) builder4id).c_str(), builder4fn.c_str(), ((string) builder4id).c_str()); - FSId fs4id = writeTerm(fs4, "", 0); + FSId fs4id = writeTerm(fs4, ""); realise(fs4id); @@ -174,7 +174,7 @@ void runTests() out5fn.c_str(), ((string) builder4fn).c_str()); debug(printTerm(fs5)); - FSId fs5id = writeTerm(fs5, "", 0); + FSId fs5id = writeTerm(fs5, ""); realise(fs5id); realise(fs5id);