scale.common
Class PragmaStk

java.lang.Object
  scale.common.PragmaStk

public final class PragmaStk
extends java.lang.Object

This class is used to hold and process #pragma information.

$Id: PragmaStk.java,v 1.5 2007-08-16 17:27:39 burrill Exp $

Copyright 2007 by the Scale Compiler Group,
Department of Computer Science
University of Massachusetts,
Amherst MA. 01003, USA
All Rights Reserved.

This implementation allows multiple pragma stacks which, in turn, allows multiple threads to compile separate source files.

The parser allocates a new PragmaStk and uses the newPragma() method to obtain the pragma that contains the appropriate information. The AST nodes can then link to this Pragma instance.

Pragmas have the following syntax:

   pragma := "#pragma" text
   text   := ["push" | "pop"] [cmd]
   cmd    := switch | unroll 
   switch := sw {"on" | "off" | "default"} 
   sw     := "STDC FP_CONTRACT" | "STDC FENV_ACCESS" |
             "STDC CX_LIMITED_RANGE" | "LOOP_PERMUTE" |
             "LOOP_TEST_AT_END"
   unroll := "UNROLL" integer
 

The push prefix causes the current pragma values to be pushed on a stack and a copy made that is then changed. The pop prefix causes the pragma values on the top of the stack to be poped off and used as the current values before being changed.

Nested Class Summary

static class

PragmaStk.Pragma

Field Summary

static int	CX_LIMITED_RANGE
static PragmaStk.Pragma	defaultPragma The default prama contains the defaults switch settings and values.
static int	FENV_ACCESS
static int	FP_CONTRACT
static int	JUST_TO_HAVE_2 Not used.
static int	LOOP_PERMUTE
static int	LOOP_TEST_AT_END
static int	UNROLL The user specified loop unrolling factor.

Constructor Summary

PragmaStk(java.lang.String filename)
Create a pragma stack to be used in processing pragma information.

Method Summary

PragmaStk.Pragma	getTop() Return the current (top) pragma entry.
boolean	newPragma(java.lang.String pragmaText, int lineno) Obtain the pragma information to be used.
static void	setDefaultFlag(int flag, boolean on) Specify the default for the specified flag.
static void	setDefaultValue(int index, int value) Specify the default for the specified value.
java.lang.String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

FP_CONTRACT

public static final int FP_CONTRACT

See Also:

Constant Field Values

FENV_ACCESS

public static final int FENV_ACCESS

See Also:

Constant Field Values

CX_LIMITED_RANGE

public static final int CX_LIMITED_RANGE

See Also:

Constant Field Values

LOOP_PERMUTE

public static final int LOOP_PERMUTE

See Also:

Constant Field Values

LOOP_TEST_AT_END

public static final int LOOP_TEST_AT_END

See Also:

Constant Field Values

UNROLL

public static final int UNROLL

The user specified loop unrolling factor. The default is 0 which means that the compiler is to determine the unroll factor. An unroll factor of 1 inhibits unrolling.

See Also:

Constant Field Values

JUST_TO_HAVE_2

public static final int JUST_TO_HAVE_2

Not used. It's here to show how new ones should be added.

See Also:

Constant Field Values

defaultPragma

public static final PragmaStk.Pragma defaultPragma

The default prama contains the defaults switch settings and values. Some are set by compiler command line switches. This pragma is used when no pragmas have been provided. For example, Fortran has no pragma-like facility.

Constructor Detail

PragmaStk

public PragmaStk(java.lang.String filename)

Create a pragma stack to be used in processing pragma information.

Parameters:

filename - is the filename of the source code that will be parsed

Method Detail

getTop

public PragmaStk.Pragma getTop()

Return the current (top) pragma entry.

setDefaultFlag

public static void setDefaultFlag(int flag,
                                  boolean on)

Specify the default for the specified flag.

setDefaultValue

public static void setDefaultValue(int index,
                                   int value)

Specify the default for the specified value.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

newPragma

public boolean newPragma(java.lang.String pragmaText,
                         int lineno)

Obtain the pragma information to be used. The text is parsed. It must be of the form (whitespace required between elements):

   text   := ["push" | "pop"] [cmd]
   cmd    := switch | unroll 
   switch := sw {"on" | "off" | "default"} 
   sw     := "STDC FP_CONTRACT" | "STDC FENV_ACCESS" |
             "STDC CX_LIMITED_RANGE" | "LOOP_PERMUTE" |
             "LOOP_TEST_AT_END"
   unroll := "UNROLL" integer
 

The push prefix causes the current pragma values to be pushed on a stack and a copy made that is then changed. The pop prefix causes the pragma values on the top of the stack to be poped off and used as the current values before being changed.

Parameters:

pragmaText - is the pragma text to be processed

lineno - is the current line in the source code

Returns:

true if the pragma was not valid