* NEWS: Document minor wording changes in diagnostics of

Bison-generated parsers.
* data/glr.c (yyMemoryExhausted): Renamed from yyStackOverflow.
Remove unused formals.  All uses changed.
(yyreportAmbiguity): "ambiguity detected" -> "syntax is ambiguous".
(yyparse): Rename yyoverflowlab to yyexhaustedlab.
* data/yacc.c (yyparse): "parser stack overflow" -> "memory exhausted".
Rename yyoverflowab to yyexhaustedlab.
When memory exhaustion occurs during syntax-error reporting,
report it separately rather than in a single diagnostic; this
eases translation.
* doc/bison.texinfo (Memory Management): Renamed from Stack Overflow.
(Memory Exhausted): Renamed from Parser Stack Overflow.
Revamp wording slightly to prefer "memory exhaustion".
* tests/actions.at: "parser stack overflow" -> "memory exhausted".
This commit is contained in:
Paul Eggert
2005-07-19 00:05:57 +00:00
parent a778f668a1
commit 1a05945136
6 changed files with 81 additions and 53 deletions

View File

@@ -267,7 +267,7 @@ The Bison Parser Algorithm
* Reduce/Reduce:: When two rules are applicable in the same situation.
* Mystery Conflicts:: Reduce/reduce conflicts that look unjustified.
* Generalized LR Parsing:: Parsing arbitrary context-free grammars.
* Stack Overflow:: What happens when stack gets full. How to avoid it.
* Memory Management:: What happens when memory is exhausted. How to avoid it.
Operator Precedence
@@ -318,7 +318,7 @@ A Complete C++ Example
Frequently Asked Questions
* Parser Stack Overflow:: Breaking the Stack Limits
* Memory Exhausted:: Breaking the Stack Limits
* How Can I Reset the Parser:: @code{yyparse} Keeps some State
* Strings are Destroyed:: @code{yylval} Loses Track of Strings
* Implementing Gotos/Loops:: Control Flow in the Calculator
@@ -4592,13 +4592,16 @@ declarations section (@pxref{Bison Declarations, ,The Bison Declarations
Section}), then Bison provides a more verbose and specific error message
string instead of just plain @w{@code{"syntax error"}}.
The parser can detect one other kind of error: stack overflow. This
happens when the input contains constructions that are very deeply
The parser can detect one other kind of error: memory exhaustion. This
can happen when the input contains constructions that are very deeply
nested. It isn't likely you will encounter this, since the Bison
parser extends its stack automatically up to a very large limit. But
if overflow happens, @code{yyparse} calls @code{yyerror} in the usual
fashion, except that the argument string is @w{@code{"parser stack
overflow"}}.
parser normally extends its stack automatically up to a very large limit. But
if memory is exhausted, @code{yyparse} calls @code{yyerror} in the usual
fashion, except that the argument string is @w{@code{"memory exhausted"}}.
In some cases diagnostics like @w{@code{"syntax error"}} are
translated automatically from English to some other language before
they are passed to @code{yyerror}. @xref{Internationalization}.
The following definition suffices in simple programs:
@@ -4961,7 +4964,7 @@ This kind of parser is known in the literature as a bottom-up parser.
* Reduce/Reduce:: When two rules are applicable in the same situation.
* Mystery Conflicts:: Reduce/reduce conflicts that look unjustified.
* Generalized LR Parsing:: Parsing arbitrary context-free grammars.
* Stack Overflow:: What happens when stack gets full. How to avoid it.
* Memory Management:: What happens when memory is exhausted. How to avoid it.
@end menu
@node Look-Ahead
@@ -5672,16 +5675,17 @@ London, Department of Computer Science, TR-00-12,
@uref{http://www.cs.rhul.ac.uk/research/languages/publications/tomita_style_1.ps},
(2000-12-24).
@node Stack Overflow
@section Stack Overflow, and How to Avoid It
@node Memory Management
@section Memory Management, and How to Avoid Memory Exhaustion
@cindex memory exhaustion
@cindex memory management
@cindex stack overflow
@cindex parser stack overflow
@cindex overflow of parser stack
The Bison parser stack can overflow if too many tokens are shifted and
The Bison parser stack can run out of memory if too many tokens are shifted and
not reduced. When this happens, the parser function @code{yyparse}
returns a nonzero value, pausing only to call @code{yyerror} to report
the overflow.
calls @code{yyerror} and then returns 2.
Because Bison parsers have growing stacks, hitting the upper limit
usually results from using a right recursion instead of a left
@@ -5689,12 +5693,12 @@ recursion, @xref{Recursion, ,Recursive Rules}.
@vindex YYMAXDEPTH
By defining the macro @code{YYMAXDEPTH}, you can control how deep the
parser stack can become before a stack overflow occurs. Define the
parser stack can become before memory is exhausted. Define the
macro with a value that is an integer. This value is the maximum number
of tokens that can be shifted (and not reduced) before overflow.
The stack space allowed is not necessarily allocated. If you specify a
large value for @code{YYMAXDEPTH}, the parser actually allocates a small
large value for @code{YYMAXDEPTH}, the parser normally allocates a small
stack at first, and then makes it bigger by stages as needed. This
increasing allocation happens automatically and silently. Therefore,
you do not need to make @code{YYMAXDEPTH} painfully small merely to save
@@ -5716,17 +5720,14 @@ macro @code{YYINITDEPTH} to a positive integer. For the C
unless you are assuming C99 or some other target language or compiler
that allows variable-length arrays. The default is 200.
Do not allow @code{YYINITDEPTH} to be a value so large that arithmetic
overflow would occur when calculating the size of the stack space.
Also, do not allow @code{YYINITDEPTH} to be greater than
@code{YYMAXDEPTH}.
Do not allow @code{YYINITDEPTH} to be greater than @code{YYMAXDEPTH}.
@c FIXME: C++ output.
Because of semantical differences between C and C++, the
@acronym{LALR}(1) parsers in C produced by Bison by compiled as C++
cannot grow. In this precise case (compiling a C parser as C++) you are
suggested to grow @code{YYINITDEPTH}. In the near future, a C++ output
output will be provided which addresses this issue.
@acronym{LALR}(1) parsers in C produced by Bison cannot grow when compiled
by C++ compilers. In this precise case (compiling a C parser as C++) you are
suggested to grow @code{YYINITDEPTH}. The Bison maintainers hope to fix
this deficiency in a future release.
@node Error Recovery
@chapter Error Recovery
@@ -7539,17 +7540,17 @@ Several questions about Bison come up occasionally. Here some of them
are addressed.
@menu
* Parser Stack Overflow:: Breaking the Stack Limits
* Memory Exhausted:: Breaking the Stack Limits
* How Can I Reset the Parser:: @code{yyparse} Keeps some State
* Strings are Destroyed:: @code{yylval} Loses Track of Strings
* Implementing Gotos/Loops:: Control Flow in the Calculator
@end menu
@node Parser Stack Overflow
@section Parser Stack Overflow
@node Memory Exhausted
@section Memory Exhausted
@display
My parser returns with error with a @samp{parser stack overflow}
My parser returns with error with a @samp{memory exhausted}
message. What can I do?
@end display
@@ -8031,7 +8032,7 @@ use for @code{YYERROR_VERBOSE}, just whether you define it. Using
@deffn {Macro} YYINITDEPTH
Macro for specifying the initial size of the parser stack.
@xref{Stack Overflow}.
@xref{Memory Management}.
@end deffn
@deffn {Function} yylex
@@ -8069,8 +8070,8 @@ variable within @code{yyparse}, and its address is passed to
@end deffn
@deffn {Macro} YYMAXDEPTH
Macro for specifying the maximum size of the parser stack. @xref{Stack
Overflow}.
Macro for specifying the maximum size of the parser stack. @xref{Memory
Management}.
@end deffn
@deffn {Variable} yynerrs