GHDL Migration Check — Vivado xsim to GHDL
Flags the VHDL lines that AMD Vivado's xsim simulator accepts but GHDL rejects or needs a flag for — before your first ghdl -a run in CI stops on them.
Tool page: https://getreadystack.com/tools/ghdl-migration-check
Yardstick: Mouser lists a Vivado ML Enterprise node-locked seat (EF-VIVADO-ENTER-NL) at $5,063.25 (checked 2026-09-29). GHDL is free under GPL-2.0.
What it checks (12 rules)
| Rule |
Line it flags |
GHDL fix |
| GH01 unisim-library |
library unisim; |
compile UNISIM with GHDL's compile-xilinx-vivado.sh, pass -P<dir> |
| GH02 xpm-macro-library |
library xpm; |
XPM macros are SystemVerilog; use an inferred VHDL FIFO/RAM or a behavioural model |
| GH03 unimacro-library |
library unimacro; |
compile with the vendor script, or generic RTL |
| GH04 secureip-library |
library secureip; |
encrypted models; stub the block |
| GH05 synopsys-packages |
use ieee.std_logic_unsigned.all; |
-fsynopsys, or better ieee.numeric_std |
| GH06 vhdl2008-process-all |
process(all) |
--std=08 (GHDL defaults to 93c) |
| GH07 vhdl2008-matching-op |
?=, ?/=, ?< … |
--std=08 |
| GH08 vhdl2008-std-env |
std.env.stop; |
--std=08, or assert … severity failure |
| GH09 vhdl2008-context |
context vunit_lib.vunit_context; |
--std=08 |
| GH10 vhdl2008-to-string |
to_string(, to_hstring( |
--std=08 |
| GH11 shared-variable-not-protected |
shared variable errors : integer; in a file that needs --std=08 |
protected type, or -frelaxed |
| GH12 encrypted-ip-envelope |
`protect begin_protected |
ask the vendor for a plain model |
If a comment in the file already sets a flag — for example -- ghdl -a --std=08 -fsynopsys — the rules that flag covers stay silent.
Measured on the sample
tb_uart_rx.vhd, a 34-line testbench that ran in Vivado xsim: 6 findings — 3 errors, 3 warnings.
| Vivado xsim line |
GHDL fix |
library unisim; |
compile UNISIM: compile-xilinx-vivado.sh |
library xpm; |
inferred VHDL FIFO, no XPM |
shared variable errors : integer |
protected type, or -frelaxed |
use ieee.std_logic_unsigned.all; |
use ieee.numeric_std.all; |
process(all) |
ghdl -a --std=08 |
std.env.stop; |
--std=08 |
Command line the file needs: ghdl -a --std=08 -fsynopsys.
How to use
- Open a
.vhd or .vhdl file.
- Run GHDL Migration Check: Check this file from the Command Palette. Findings appear in the Problems panel with the fix in the message.
- Or paste the file into the free web page at the tool link above — same engine, nothing uploaded.
Free and full version
Free, no key: check the open file, every finding, every fix, the ghdl -a command line.
Full version ($29 once, one licence key per person or team seat): scan every .vhd file in the workspace in one pass and export a Markdown migration report with the flag set per library. Get the full version
Sources
