Add a wrapper script for the instruction generator build

This is the first such script, but the idea is that we're going to
move a bunch of logic out of the Makefile and into Python scripts
where things are a bit easier to understand.

dv/uvm/core_ibex/Makefile

@@ -99,6 +99,10 @@ OUT-DIR := $(dir $(OUT)/)
 # get printed when VERBOSE.
 verb = $(if $(filter-out 0,$(VERBOSE)),,@)
 
+# Like verb, but expands to --verbose if we're in verbose mode (used
+# for running sub-commands)
+verb-arg = $(if $(filter-out 0,$(VERBOSE)),--verbose,)
+
 SHELL=/bin/bash
 
 export PRJ_DIR:= $(realpath ../../..)
@@ -286,15 +290,15 @@ risc-dv-files := $(shell find $(GEN_DIR) -type f)
 # than running it for every target otherwise.
 
 $(metadata)/.instr_gen.build.stamp: \
-  $(instr-gen-build-vars-prereq) $(risc-dv-files) | $(metadata)
+  $(instr-gen-build-vars-prereq) \
+  $(risc-dv-files) scripts/build-instr-gen.py | $(metadata)
 	$(verb)rm -rf $(OUT-SEED)/instr_gen
-	$(verb)python3 ${GEN_DIR}/run.py \
-	       --co --steps=gen \
-	       --output=$(OUT-SEED)/instr_gen \
-	       --simulator="${SIMULATOR}" \
-	       ${_RISCV_DV_OPTS} \
-	       --isa=${ISA} \
-	       ${CSR_OPTS}
+	$(verb)scripts/build-instr-gen.py        \
+	  $(verb-arg)                            \
+	  --simulator $(SIMULATOR)               \
+	  --end-signature-addr $(SIGNATURE_ADDR) \
+	  --output $(OUT-SEED)/instr_gen         \
+	  --isa $(ISA)
 	$(call dump-vars,$(metadata)/.instr_gen.build.vars.mk,gen,$(instr-gen-build-var-deps))
 	@touch $@
 

dv/uvm/core_ibex/scripts/build-instr-gen.py

@@ -0,0 +1,34 @@
+#!/usr/bin/env python3
+
+# Copyright lowRISC contributors.
+# Licensed under the Apache License, Version 2.0, see LICENSE for details.
+# SPDX-License-Identifier: Apache-2.0
+
+import argparse
+import sys
+
+from scripts_lib import run_one, start_riscv_dv_run_cmd
+
+
+def main() -> int:
+    parser = argparse.ArgumentParser()
+    parser.add_argument('--verbose', action='store_true')
+    parser.add_argument('--simulator', required=True)
+    parser.add_argument('--end-signature-addr', required=True)
+    parser.add_argument('--output', required=True)
+    parser.add_argument('--isa', required=True)
+
+    args = parser.parse_args()
+
+    cmd = (start_riscv_dv_run_cmd(args.verbose) +
+           ['--co', '--steps=gen',
+            '--simulator', args.simulator,
+            '--output', args.output,
+            '--isa', args.isa,
+            '--end_signature_addr', args.end_signature_addr])
+
+    return run_one(args.verbose, cmd)
+
+
+if __name__ == '__main__':
+    sys.exit(main())

dv/uvm/core_ibex/scripts/scripts_lib.py

@@ -0,0 +1,47 @@
+#!/usr/bin/env python3
+# Copyright lowRISC contributors.
+# Licensed under the Apache License, Version 2.0, see LICENSE for details.
+# SPDX-License-Identifier: Apache-2.0
+
+import os
+import shlex
+import subprocess
+import sys
+from typing import List
+
+THIS_DIR = os.path.dirname(__file__)
+IBEX_ROOT = os.path.join(THIS_DIR, 4 * '../')
+RISCV_DV_ROOT = os.path.normpath(os.path.join(IBEX_ROOT,
+                                              'vendor/google_riscv-dv'))
+
+
+def run_one(verbose: bool, cmd: List[str]) -> int:
+    if verbose:
+        # The equivalent of bash -x
+        print('+ ' + ' '.join(shlex.quote(w) for w in cmd),
+              file=sys.stderr)
+
+    # Passing close_fds=False ensures that if cmd is a call to Make then we'll
+    # pass through the jobserver fds. If you don't do this, you get a warning
+    # starting "warning: jobserver unavailable".
+    return subprocess.run(cmd, close_fds=False).returncode
+
+
+def start_riscv_dv_run_cmd(verbose: bool):
+    '''Return the command parts of a call to riscv-dv's run.py'''
+    riscv_dv_extension = os.path.join(THIS_DIR, '../riscv_dv_extension')
+
+    csr_desc = os.path.join(riscv_dv_extension, 'csr_description.yaml')
+    testlist = os.path.join(riscv_dv_extension, 'testlist.yaml')
+
+    cmd = ['python3',
+           os.path.join(RISCV_DV_ROOT, 'run.py'),
+           '--testlist', testlist,
+           '--gcc_opts=-mno-strict-align',
+           '--custom_target', riscv_dv_extension,
+           '--csr_yaml', csr_desc,
+           '--mabi=ilp32']
+    if verbose:
+        cmd.append('--verbose')
+
+    return cmd