( ESNUG 248 Item 4 ) -------------------------------------------- [8/22/96]
From: Iain Finlay <ifinlay@qualcomm.com>
Subject: Intermittent VHDL 3.3a Elaboration w/ Multiple Libraries
Hi John,
We have experienced intermittent problems with the following design
library setup (see below). The "elaborate" command occasionally fails
to link in a component or two from a separate, but correctly
referenced, design library.
Design library: "A" contains a VHDL package of constants.
Design library: "B" references "A" and contains
(1) a VHDL package of functions
(2) a VHDL component package and the corresponding
entity-architecture implementations - some of these
are parameterized (i.e. a fifo)
Design library: "DEFAULT" contains the design source.
WORK points to this library.
Assume there is a design entity "D" in the design library default.
1) the symptom:
dc_shell> elaborate
produces some message saying that it "can't find synthetic module
"FIFO..." in library 'WORK'.
2) FIFO exists in library "B":
dc_shell> report_design_lib -lib
reports that "B" is defined and points to the appropriate unix directory.
dc_shell> report_design_lib B
lists the contents of B showing that FIFO exists and is up-to-date.
3) confirmation:
dc_shell> elaborate FIFO -lib B
works !
NOTE: this problem occurs for both parameterized and non-parameterized parts.
This problem has been lurking around for some time. We've checked that
the VHDL source uses the appropriate "library" and "use" clauses; that
the design libraries are correctly defined and contain the correct,
properly analyzed source (and are on the search path).
Unfortunately, every time we try to extract a small test case from our
environment the problem evaporates. Often the problem disappears after
deleting all analyzed files and re-analyzing everything. We've just
been unable to isolate the factor(s) which trigger this problem.
We'd like to know if anyone else has experienced this and if they
have a better idea of the cause. Our only workaround is to throw
everything into the WORK library.
- Iain W. Finlay
Qualcomm, Inc.
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