LEF to OpenAccess Translator (lef2oa)

The LEF to OpenAccess Translator imports a file in the LEF format into a technology database and in some cases design data in the OpenAccess library structure. LEF contains technology information, design rules, macro cell definitions, and information about design objects such as vias, sites, and layers. LEF to OpenAccess is available from the command line through the executable lef2oa. A LEF file and destination library are required to begin a translation.

Command Syntax

To run lef2oa, enter the following:

lef2oa -lef file -lib library  [Optional Arguments]

Use the -help or -h argument to display command-line help. The command-line arguments are described in the following table.

    lef2oa ... -DMAttributes "name1=value name2=value name3=value"

   <layerName>  <layerNumber>

# Example layer map file
#layerName  	layerNumber
   Metal1        1 
   Via1          2
   Metal2        3
   Via2          4
   Metal3        5
   Via3          6
   Metal4        7
   Via4          8
   Metal5        9
   Via5          10

logFile        mylef2oa.log
layerMap       mylefmap.txt
pinLabels
update

Note: Command line arguments specifying library, cell, and view names are interpreted according to the Native name space. See Native Name Space in the Name Mapping article of the Programmers Guide for details about the native name space.

The following is an example of lef2oa command line syntax.

    lef2oa -lef ac36.lef -lib ac36 -libPath /db/myProject/cds/ac36 -techLib techLib2  \
    -techLibPath /db/myProject/cds/techLib2/ -view abstract2 -layerMap layerMap.txt 

For information about how lef2oa can be used to work with incremental technology databases, refer to Translator Support in the Using Technology Databases section of the Programmers Guide.

How the Translator Uses Namespaces

A namespace is a set of rules that define the legal characters and determine how names are interpretted. This translator uses the oaNative namespace to interpret library, cell, and view names in the command line. Other names that refer to name-mapped OpenAccess objects, such as net and module names, use the LEF namespace.

Merging Verilog and LEF/DEF Information

If you need to merge Verilog and LEF/DEF information, you must follow a particular sequence of steps. Refer to the verilog2oa documentation and the section Creating a Design by Merging Verilog and LEF/DEF Information for the steps you must follow.

Error Handling

If an error occurs during translation, usually the translator can emit a warning or error message and continue. However, certain translation errors halt further translation. The manner in which translation errors are handled depend on the type of error.

• Parse Error The translator issues *Parse Error* (instead of an error ID and message) and translation is halted.
• OpenAccess Data Creation Error The translator issues an error message, proceeds to the next object, and continues translation.
• Special Case If the translator encounters OBS/PIN geometry with missing layers, a warning message is issued, translation of the geometry with missing layers is skipped, and translation of the next shape continues.

Error and Warning Message Format

Translators emit messages that report translation progress, report warnings about unusual data or conditions, or report problems with files or data that caused partial or complete translation failure. These messages are written to a log file so you can review translation status, identify error and warning conditions, and consider whether additional actions are needed.

OpenAccess translators use a standard message format to ensure comprehensive and consistent messaging. This message format consists of three elements, which are: message type keyword, message prefix, and message text. The message text can be further divided into three parts. The first part indicates what caused the message, the second indicates the consequence of the problem or condition, and the third part suggests an action you can take to remedy the problem or condition.

In addition to the three standard elements, messages can also include two optional elements. An optional filename and optional line number element are included, when available, to more precisely identify the source of a problem or condition within the source data file. When present in an error or warning message, the filename and line number correspond to the location of the last line parsed for the object, and therefore, the cause of the error or warning can occur on a line preceding the indicated line number. A context string is another optional element that is included, when available, to identify the type of data object that caused the message to be emitted. Following is an example of an error message that includes the optional filename and line number element.

    ERROR: (OALEFDEF-50004): file.lef(123): A cell was not specified. Translation was terminated. 
    You must specify a cell.

One benefit of this message format is that it allows you to sort, filter, and examine only those types of messages that interest you. The keyword at the start of each message is either ERROR or WARNING and is always all uppercase. The message prefix identifies the translator family and the specific message source within the translator. The message prefix is a stable value that will not change between versions even when the message text gets updated. This makes it suitable for routine sorting and filtering.

If you seek assistance for resolving an issue related to a translator error or warning message, be sure to retain the message type keyword (ERROR or WARNING), and retain the message prefix to identify the translator family and the message source. Also make note of the filename/line number and context information if these are included in the message.

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