riscv
/
yosys
mirror of https://github.com/YosysHQ/yosys.git
1
0
Fork 0
Code Issues Projects Releases Wiki Activity

Small fixes and improvements in $allconst/$allseq handling 

Signed-off-by: Clifford Wolf <clifford@clifford.at>
This commit is contained in:
Clifford Wolf 2018-02-26 11:58:44 +01:00
parent fba499b866
commit 675dd5347a
2 changed files with 23 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
README.md
View File

@ -396,10 +396,11 @@ Non-standard or SystemVerilog features for formal verification
but also works outside of checkers. (Yosys also supports ``rand``
variables outside checkers.)
- The system functions ``$allconst`` and ``$allseq`` are used to construct formal
exist-forall problems. Assertions are only violated if the trace vialoates
the assertion for all ``$allconst/$allseq`` values and assumptions only hold
if the trace satisfies the assumtion for all ``$allconst/$allseq`` values.
- The system functions ``$allconst`` and ``$allseq`` can be used to construct
formal exist-forall problems. Assumptions only hold if the trace satisfies
the assumtion for all ``$allconst/$allseq`` values. For assertions and cover
statements it is sufficient if just one ``$allconst/$allseq`` value triggers
the property (similar to ``$anyconst/$anyseq``).
- The SystemVerilog tasks ``$past``, ``$stable``, ``$rose`` and ``$fell`` are
supported in any clocked block.

30
backends/smt2/smtbmc.py
View File

@ -1019,6 +1019,12 @@ def smt_state(step):
smt.write("(declare-fun s%d () |%s_s|)" % (step, topmod))
states.append("s%d" % step)
def smt_assert(expr):
if expr == "true":
return
smt.write("(assert %s)" % expr)
def smt_assert_antecedent(expr):
if expr == "true":
return
@ -1158,12 +1164,12 @@ if tempind:
smt_assert_consequent(get_constr_expr(constr_assumes, step))
if step == num_steps:
smt_assert_consequent("(not (and (|%s_a| s%d) %s))" % (topmod, step, get_constr_expr(constr_asserts, step)))
smt_assert("(not (and (|%s_a| s%d) %s))" % (topmod, step, get_constr_expr(constr_asserts, step)))
else:
smt_assert_antecedent("(|%s_t| s%d s%d)" % (topmod, step, step+1))
smt_assert_consequent("(|%s_a| s%d)" % (topmod, step))
smt_assert_consequent(get_constr_expr(constr_asserts, step))
smt_assert("(|%s_a| s%d)" % (topmod, step))
smt_assert(get_constr_expr(constr_asserts, step))
if step > num_steps-skip_steps:
print_msg("Skipping induction in step %d.." % (step))
@ -1234,7 +1240,7 @@ elif covermode:
while "1" in cover_mask:
print_msg("Checking cover reachability in step %d.." % (step))
smt_push()
smt_assert_antecedent("(distinct (covers_%d s%d) #b%s)" % (coveridx, step, "0" * len(cover_desc)))
smt_assert("(distinct (covers_%d s%d) #b%s)" % (coveridx, step, "0" * len(cover_desc)))
if smt_check_sat() == "unsat":
smt_pop()
@ -1317,8 +1323,8 @@ else: # not tempind, covermode
if step < skip_steps:
if assume_skipped is not None and step >= assume_skipped:
print_msg("Skipping step %d (and assuming pass).." % (step))
smt_assert_consequent("(|%s_a| s%d)" % (topmod, step))
smt_assert_consequent(get_constr_expr(constr_asserts, step))
smt_assert("(|%s_a| s%d)" % (topmod, step))
smt_assert(get_constr_expr(constr_asserts, step))
else:
print_msg("Skipping step %d.." % (step))
step += 1
@ -1354,7 +1360,7 @@ else: # not tempind, covermode
print_msg("Checking assertions in steps %d to %d.." % (step, last_check_step))
smt_push()
smt_assert_consequent("(not (and %s))" % " ".join(["(|%s_a| s%d)" % (topmod, i) for i in range(step, last_check_step+1)] +
smt_assert("(not (and %s))" % " ".join(["(|%s_a| s%d)" % (topmod, i) for i in range(step, last_check_step+1)] +
[get_constr_expr(constr_asserts, i) for i in range(step, last_check_step+1)]))
if smt_check_sat() == "sat":
@ -1380,8 +1386,8 @@ else: # not tempind, covermode
if (constr_final_start is not None) or (last_check_step+1 != num_steps):
for i in range(step, last_check_step+1):
smt_assert_consequent("(|%s_a| s%d)" % (topmod, i))
smt_assert_consequent(get_constr_expr(constr_asserts, i))
smt_assert("(|%s_a| s%d)" % (topmod, i))
smt_assert(get_constr_expr(constr_asserts, i))
if constr_final_start is not None:
for i in range(step, last_check_step+1):
@ -1392,7 +1398,7 @@ else: # not tempind, covermode
smt_push()
smt_assert_consequent(get_constr_expr(constr_assumes, i, final=True))
smt_assert_consequent("(not %s)" % get_constr_expr(constr_asserts, i, final=True))
smt_assert("(not %s)" % get_constr_expr(constr_asserts, i, final=True))
if smt_check_sat() == "sat":
print("%s BMC failed!" % smt.timestamp())
@ -1408,8 +1414,8 @@ else: # not tempind, covermode
else: # gentrace
for i in range(step, last_check_step+1):
smt_assert_consequent("(|%s_a| s%d)" % (topmod, i))
smt_assert_consequent(get_constr_expr(constr_asserts, i))
smt_assert("(|%s_a| s%d)" % (topmod, i))
smt_assert(get_constr_expr(constr_asserts, i))
print_msg("Solving for step %d.." % (last_check_step))
if smt_check_sat() != "sat":