From 0a7746603eda58c4b368e977e87d0aa4db397f5b Mon Sep 17 00:00:00 2001 From: pennae Date: Wed, 19 Jan 2022 13:39:42 +0100 Subject: [PATCH] remove ExprIndStr MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit it can be replaced with StringToken if we add another bit if information to StringToken, namely whether this string should take part in indentation scanning or not. since all escaping terminates indentation scanning we need to set this bit only for the non-escaped IND_STRING rule. this improves performance by about 1%. before nix search --no-eval-cache --offline ../nixpkgs hello Time (mean ± σ): 8.880 s ± 0.048 s [User: 6.809 s, System: 1.643 s] Range (min … max): 8.781 s … 8.993 s 20 runs nix eval -f ../nixpkgs/pkgs/development/haskell-modules/hackage-packages.nix Time (mean ± σ): 375.0 ms ± 2.2 ms [User: 339.8 ms, System: 35.2 ms] Range (min … max): 371.5 ms … 379.3 ms 20 runs nix eval --raw --impure --expr 'with import {}; system' Time (mean ± σ): 2.831 s ± 0.040 s [User: 2.536 s, System: 0.225 s] Range (min … max): 2.769 s … 2.912 s 20 runs after nix search --no-eval-cache --offline ../nixpkgs hello Time (mean ± σ): 8.832 s ± 0.048 s [User: 6.757 s, System: 1.657 s] Range (min … max): 8.743 s … 8.921 s 20 runs nix eval -f ../nixpkgs/pkgs/development/haskell-modules/hackage-packages.nix Time (mean ± σ): 367.4 ms ± 3.2 ms [User: 332.7 ms, System: 34.7 ms] Range (min … max): 364.6 ms … 374.6 ms 20 runs nix eval --raw --impure --expr 'with import {}; system' Time (mean ± σ): 2.810 s ± 0.030 s [User: 2.517 s, System: 0.225 s] Range (min … max): 2.742 s … 2.854 s 20 runs --- src/libexpr/lexer.l | 18 ++++----- src/libexpr/nixexpr.hh | 7 ---- src/libexpr/parser.y | 86 +++++++++++++++++++++++------------------- 3 files changed, 57 insertions(+), 54 deletions(-) diff --git a/src/libexpr/lexer.l b/src/libexpr/lexer.l index a0e7a1877..e276b0467 100644 --- a/src/libexpr/lexer.l +++ b/src/libexpr/lexer.l @@ -66,7 +66,7 @@ static void adjustLoc(YYLTYPE * loc, const char * s, size_t len) // we make use of the fact that the parser receives a private copy of the input // string and can munge around in it. -static Expr * unescapeStr(SymbolTable & symbols, char * s, size_t length) +static StringToken unescapeStr(SymbolTable & symbols, char * s, size_t length) { char * result = s; char * t = s; @@ -89,7 +89,7 @@ static Expr * unescapeStr(SymbolTable & symbols, char * s, size_t length) else *t = c; t++; } - return new ExprString(symbols.create({result, size_t(t - result)})); + return {result, size_t(t - result)}; } @@ -176,7 +176,7 @@ or { return OR_KW; } /* It is impossible to match strings ending with '$' with one regex because trailing contexts are only valid at the end of a rule. (A sane but undocumented limitation.) */ - yylval->e = unescapeStr(data->symbols, yytext, yyleng); + yylval->str = unescapeStr(data->symbols, yytext, yyleng); return STR; } \$\{ { PUSH_STATE(DEFAULT); return DOLLAR_CURLY; } @@ -191,26 +191,26 @@ or { return OR_KW; } \'\'(\ *\n)? { PUSH_STATE(IND_STRING); return IND_STRING_OPEN; } ([^\$\']|\$[^\{\']|\'[^\'\$])+ { - yylval->e = new ExprIndStr(yytext); + yylval->str = {yytext, (size_t) yyleng, true}; return IND_STR; } \'\'\$ | \$ { - yylval->e = new ExprIndStr("$"); + yylval->str = {"$", 1}; return IND_STR; } \'\'\' { - yylval->e = new ExprIndStr("''"); + yylval->str = {"''", 2}; return IND_STR; } \'\'\\{ANY} { - yylval->e = unescapeStr(data->symbols, yytext + 2, yyleng - 2); + yylval->str = unescapeStr(data->symbols, yytext + 2, yyleng - 2); return IND_STR; } \$\{ { PUSH_STATE(DEFAULT); return DOLLAR_CURLY; } \'\' { POP_STATE(); return IND_STRING_CLOSE; } \' { - yylval->e = new ExprIndStr("'"); + yylval->str = {"'", 1}; return IND_STR; } @@ -264,7 +264,7 @@ or { return OR_KW; } PUSH_STATE(INPATH_SLASH); else PUSH_STATE(INPATH); - yylval->e = new ExprString(data->symbols.create(string(yytext))); + yylval->str = {yytext, (size_t) yyleng}; return STR; } {ANY} | diff --git a/src/libexpr/nixexpr.hh b/src/libexpr/nixexpr.hh index 0a60057e5..ae11560ea 100644 --- a/src/libexpr/nixexpr.hh +++ b/src/libexpr/nixexpr.hh @@ -117,13 +117,6 @@ struct ExprString : Expr Value * maybeThunk(EvalState & state, Env & env); }; -/* Temporary class used during parsing of indented strings. */ -struct ExprIndStr : Expr -{ - string s; - ExprIndStr(const string & s) : s(s) { }; -}; - struct ExprPath : Expr { string s; diff --git a/src/libexpr/parser.y b/src/libexpr/parser.y index a3e713937..38b218156 100644 --- a/src/libexpr/parser.y +++ b/src/libexpr/parser.y @@ -16,6 +16,8 @@ #ifndef BISON_HEADER #define BISON_HEADER +#include + #include "util.hh" #include "nixexpr.hh" @@ -41,6 +43,15 @@ namespace nix { } +// using C a struct allows us to avoid having to define the special +// members that using string_view here would implicitly delete. +struct StringToken { + const char * p; + size_t l; + bool hasIndentation; + operator std::string_view() const { return {p, l}; } +}; + #define YY_DECL int yylex \ (YYSTYPE * yylval_param, YYLTYPE * yylloc_param, yyscan_t yyscanner, nix::ParseData * data) @@ -152,7 +163,8 @@ static void addFormal(const Pos & pos, Formals * formals, const Formal & formal) } -static Expr * stripIndentation(const Pos & pos, SymbolTable & symbols, vector > & es) +static Expr * stripIndentation(const Pos & pos, SymbolTable & symbols, + vector > > & es) { if (es.empty()) return new ExprString(symbols.create("")); @@ -163,20 +175,20 @@ static Expr * stripIndentation(const Pos & pos, SymbolTable & symbols, vector(i); - if (!e) { - /* Anti-quotations end the current start-of-line whitespace. */ + auto * str = std::get_if(&i); + if (!str || !str->hasIndentation) { + /* Anti-quotations and escaped characters end the current start-of-line whitespace. */ if (atStartOfLine) { atStartOfLine = false; if (curIndent < minIndent) minIndent = curIndent; } continue; } - for (size_t j = 0; j < e->s.size(); ++j) { + for (size_t j = 0; j < str->l; ++j) { if (atStartOfLine) { - if (e->s[j] == ' ') + if (str->p[j] == ' ') curIndent++; - else if (e->s[j] == '\n') { + else if (str->p[j] == '\n') { /* Empty line, doesn't influence minimum indentation. */ curIndent = 0; @@ -184,7 +196,7 @@ static Expr * stripIndentation(const Pos & pos, SymbolTable & symbols, vectors[j] == '\n') { + } else if (str->p[j] == '\n') { atStartOfLine = true; curIndent = 0; } @@ -196,33 +208,31 @@ static Expr * stripIndentation(const Pos & pos, SymbolTable & symbols, vector >::iterator i = es.begin(); i != es.end(); ++i, --n) { - ExprIndStr * e = dynamic_cast(i->second); - if (!e) { - atStartOfLine = false; - curDropped = 0; - es2->push_back(*i); - continue; - } - + auto i = es.begin(); + const auto trimExpr = [&] (Expr * e) { + atStartOfLine = false; + curDropped = 0; + es2->emplace_back(i->first, e); + }; + const auto trimString = [&] (const StringToken & t) { string s2; - for (size_t j = 0; j < e->s.size(); ++j) { + for (size_t j = 0; j < t.l; ++j) { if (atStartOfLine) { - if (e->s[j] == ' ') { + if (t.p[j] == ' ') { if (curDropped++ >= minIndent) - s2 += e->s[j]; + s2 += t.p[j]; } - else if (e->s[j] == '\n') { + else if (t.p[j] == '\n') { curDropped = 0; - s2 += e->s[j]; + s2 += t.p[j]; } else { atStartOfLine = false; curDropped = 0; - s2 += e->s[j]; + s2 += t.p[j]; } } else { - s2 += e->s[j]; - if (e->s[j] == '\n') atStartOfLine = true; + s2 += t.p[j]; + if (t.p[j] == '\n') atStartOfLine = true; } } @@ -235,6 +245,9 @@ static Expr * stripIndentation(const Pos & pos, SymbolTable & symbols, vectoremplace_back(i->first, new ExprString(symbols.create(s2))); + }; + for (; i != es.end(); ++i, --n) { + std::visit(overloaded { trimExpr, trimString }, i->second); } /* If this is a single string, then don't do a concatenation. */ @@ -273,18 +286,13 @@ void yyerror(YYLTYPE * loc, yyscan_t scanner, ParseData * data, const char * err nix::Formal * formal; nix::NixInt n; nix::NixFloat nf; - // using C a struct allows us to avoid having to define the special - // members that using string_view here would implicitly delete. - struct StringToken { - const char * p; - size_t l; - operator std::string_view() const { return {p, l}; } - }; StringToken id; // !!! -> Symbol StringToken path; StringToken uri; + StringToken str; std::vector * attrNames; std::vector > * string_parts; + std::vector > > * ind_string_parts; } %type start expr expr_function expr_if expr_op @@ -294,11 +302,12 @@ void yyerror(YYLTYPE * loc, yyscan_t scanner, ParseData * data, const char * err %type formals %type formal %type attrs attrpath -%type string_parts_interpolated ind_string_parts +%type string_parts_interpolated +%type ind_string_parts %type path_start string_parts string_attr %type attr %token ID ATTRPATH -%token STR IND_STR +%token STR IND_STR %token INT %token FLOAT %token PATH HPATH SPATH PATH_END @@ -449,18 +458,19 @@ expr_simple ; string_parts - : STR + : STR { $$ = new ExprString(data->symbols.create($1)); } | string_parts_interpolated { $$ = new ExprConcatStrings(CUR_POS, true, $1); } | { $$ = new ExprString(data->symbols.create("")); } ; string_parts_interpolated - : string_parts_interpolated STR { $$ = $1; $1->emplace_back(makeCurPos(@2, data), $2); } + : string_parts_interpolated STR + { $$ = $1; $1->emplace_back(makeCurPos(@2, data), new ExprString(data->symbols.create($2))); } | string_parts_interpolated DOLLAR_CURLY expr '}' { $$ = $1; $1->emplace_back(makeCurPos(@2, data), $3); } | DOLLAR_CURLY expr '}' { $$ = new vector >; $$->emplace_back(makeCurPos(@1, data), $2); } | STR DOLLAR_CURLY expr '}' { $$ = new vector >; - $$->emplace_back(makeCurPos(@1, data), $1); + $$->emplace_back(makeCurPos(@1, data), new ExprString(data->symbols.create($1))); $$->emplace_back(makeCurPos(@2, data), $3); } ; @@ -482,7 +492,7 @@ path_start ind_string_parts : ind_string_parts IND_STR { $$ = $1; $1->emplace_back(makeCurPos(@2, data), $2); } | ind_string_parts DOLLAR_CURLY expr '}' { $$ = $1; $1->emplace_back(makeCurPos(@2, data), $3); } - | { $$ = new vector >; } + | { $$ = new vector > >; } ; binds