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With --bbox-ignore, don't warn about always order.

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This commit is contained in:
Wilson Snyder 2015-10-24 07:24:53 -04:00
parent 4464b13163
commit 4f269e336d
3 changed files with 61 additions and 9 deletions
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19
src/V3Undriven.cpp
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@ -229,7 +229,7 @@ private:
// STATE
vector<UndrivenVarEntry*> m_entryps[3]; // Nodes to delete when we are finished
bool m_markBoth; // Mark as driven+used
bool m_inBBox; // In black box; mark as driven+used
AstNodeFTask* m_taskp; // Current task
AstAlways* m_alwaysp; // Current always
@ -258,6 +258,7 @@ private:
void warnAlwCombOrder(AstVarRef* nodep) {
AstVar* varp = nodep->varp();
if (!varp->isParam() && !varp->isGenVar() && !varp->isUsedLoopIdx()
&& !m_inBBox // We may have falsely considered a SysIgnore as a driver
&& !varp->fileline()->warnIsOff(V3ErrorCode::ALWCOMBORDER)) { // Warn only once per variable
nodep->v3warn(ALWCOMBORDER, "Always_comb variable driven after use: "<<nodep->prettyName());
varp->fileline()->modifyWarnOff(V3ErrorCode::ALWCOMBORDER, true); // Complain just once for any usage
@ -294,7 +295,7 @@ private:
for (int usr=1; usr<(m_alwaysp?3:2); ++usr) {
UndrivenVarEntry* entryp = getEntryp (varrefp->varp(), usr);
int lsb = constp->toUInt();
if (m_markBoth || varrefp->lvalue()) {
if (m_inBBox || varrefp->lvalue()) {
// Don't warn if already driven earlier as "a=0; if(a) a=1;" is fine.
if (usr==2 && m_alwaysp && entryp->isUsedNotDrivenBit(lsb, nodep->width())) {
UINFO(9," Select. Entryp="<<(void*)entryp<<endl);
@ -302,7 +303,7 @@ private:
}
entryp->drivenBit(lsb, nodep->width());
}
if (m_markBoth || !varrefp->lvalue()) entryp->usedBit(lsb, nodep->width());
if (m_inBBox || !varrefp->lvalue()) entryp->usedBit(lsb, nodep->width());
}
} else {
// else other varrefs handled as unknown mess in AstVarRef
@ -314,23 +315,23 @@ private:
for (int usr=1; usr<(m_alwaysp?3:2); ++usr) {
UndrivenVarEntry* entryp = getEntryp (nodep->varp(), usr);
bool fdrv = nodep->lvalue() && nodep->varp()->attrFileDescr(); // FD's are also being read from
if (m_markBoth || nodep->lvalue()) {
if (m_inBBox || nodep->lvalue()) {
if (usr==2 && m_alwaysp && entryp->isUsedNotDrivenAny()) {
UINFO(9," Full bus. Entryp="<<(void*)entryp<<endl);
warnAlwCombOrder(nodep);
}
entryp->drivenWhole();
}
if (m_markBoth || !nodep->lvalue() || fdrv) entryp->usedWhole();
if (m_inBBox || !nodep->lvalue() || fdrv) entryp->usedWhole();
}
}
// Don't know what black boxed calls do, assume in+out
virtual void visit(AstSysIgnore* nodep, AstNUser*) {
bool prevMark = m_markBoth;
m_markBoth = true;
bool prevMark = m_inBBox;
m_inBBox = true;
nodep->iterateChildren(*this);
m_markBoth = prevMark;
m_inBBox = prevMark;
}
virtual void visit(AstAlways* nodep, AstNUser*) {
@ -371,7 +372,7 @@ private:
public:
// CONSTUCTORS
explicit UndrivenVisitor(AstNetlist* nodep) {
m_markBoth = false;
m_inBBox = false;
m_taskp = NULL;
m_alwaysp = NULL;
nodep->accept(*this);

21
test_regress/t/t_lint_comb_use.pl Executable file
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@ -0,0 +1,21 @@
#!/usr/bin/perl
if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
# DESCRIPTION: Verilator: Verilog Test driver/expect definition
#
# Copyright 2008 by Wilson Snyder. This program is free software; you can
# redistribute it and/or modify it under the terms of either the GNU
# Lesser General Public License Version 3 or the Perl Artistic License
# Version 2.0.
$Self->{vlt} or $Self->skip("Verilator only test");
compile (
verilator_flags2 => ["--lint-only --bbox-sys"],
fails=>0,
verilator_make_gcc => 0,
make_top_shell => 0,
make_main => 0,
);
ok(1);
1;

30
test_regress/t/t_lint_comb_use.v Normal file
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@ -0,0 +1,30 @@
// DESCRIPTION: Verilator: Verilog Test module
//
// This file ONLY is placed into the Public Domain, for any use,
// without warranty, 2010 by Wilson Snyder.
module t (/*AUTOARG*/
// Outputs
hval,
// Inputs
sel
);
input logic [2:0] sel;
output logic [3:0] hval;
/*AUTOINPUT*/
/*AUTOOUTPUT*/
always_comb begin
unique case (sel)
3'h0: hval = 4'hd;
3'h1: hval = 4'hc;
3'h7: hval = 4'hf;
default: begin
$ignore ("ERROR : %s [%m]", $sformatf ("Illegal sel = %x", sel));
hval = 4'bx;
end
endcase
end
endmodule