Add --fno-inline-funcs to disable function inlining.

Changes

@@ -29,6 +29,7 @@ Verilator 5.031 devel
 * Add coverage point hierarchy to coverage reports (#5575) (#5576). [Andrew Nolte]
 * Add warning on global constraints (#5625). [Ryszard Rozak, Antmicro Ltd.]
 * Add error on `solve before` or soft constraints of `randc` variable.
+* Add `--fno-inline-funcs` to disable function inlining.
 * Improve concatenation performance (#5598) (#5599) (#5602). [Geza Lore]
 * Fix dotted reference in delay value (#2410).
 * Fix `function fork...join_none` regression with unknown type (#4449).

docs/guide/exe_verilator.rst

@@ -599,6 +599,8 @@ Summary:
 
 .. option:: -fno-inline
 
+.. option:: -fno-inline-funcs
+
 .. option:: -fno-life
 
 .. option:: -fno-life-post

src/V3Options.cpp

@@ -1317,6 +1317,7 @@ void V3Options::parseOptsList(FileLine* fl, const string& optdir, int argc,
     DECL_OPTION("-ffunc-opt-split-cat", FOnOff, &m_fFuncSplitCat);
     DECL_OPTION("-fgate", FOnOff, &m_fGate);
     DECL_OPTION("-finline", FOnOff, &m_fInline);
+    DECL_OPTION("-finline-funcs", FOnOff, &m_fInlineFuncs);
     DECL_OPTION("-flife", FOnOff, &m_fLife);
     DECL_OPTION("-flife-post", FOnOff, &m_fLifePost);
     DECL_OPTION("-flocalize", FOnOff, &m_fLocalize);

src/V3Options.h

@@ -390,6 +390,7 @@ private:
     bool m_fFuncSplitCat = true;  // main switch: -fno-func-split-cat: expansion of C macros
     bool m_fGate;        // main switch: -fno-gate: gate wire elimination
     bool m_fInline;      // main switch: -fno-inline: module inlining
+    bool m_fInlineFuncs = true;  // main switch: -fno-inline-funcs: function inlining
     bool m_fLife;        // main switch: -fno-life: variable lifetime
     bool m_fLifePost;    // main switch: -fno-life-post: delayed assignment elimination
     bool m_fLocalize;    // main switch: -fno-localize: convert temps to local variables
@@ -685,6 +686,7 @@ public:
     bool fFunc() const { return fFuncSplitCat() || fFuncBalanceCat(); }
     bool fGate() const { return m_fGate; }
     bool fInline() const { return m_fInline; }
+    bool fInlineFuncs() const { return m_fInlineFuncs; }
     bool fLife() const { return m_fLife; }
     bool fLifePost() const { return m_fLifePost; }
     bool fLocalize() const { return m_fLocalize; }

src/V3Task.cpp

@@ -30,6 +30,7 @@
 #include "V3Const.h"
 #include "V3EmitCBase.h"
 #include "V3Graph.h"
+#include "V3Stats.h"
 
 #include <tuple>
 
@@ -132,7 +133,9 @@ public:
     void remapFuncClassp(AstNodeFTask* nodep, AstNodeFTask* newp) {
         m_funcToClassMap[newp] = getClassp(nodep);
     }
-    bool ftaskNoInline(AstNodeFTask* nodep) { return getFTaskVertex(nodep)->noInline(); }
+    bool ftaskNoInline(AstNodeFTask* nodep) {
+        return !v3Global.opt.fInlineFuncs() || getFTaskVertex(nodep)->noInline();
+    }
     AstCFunc* ftaskCFuncp(AstNodeFTask* nodep) { return getFTaskVertex(nodep)->cFuncp(); }
     void ftaskCFuncp(AstNodeFTask* nodep, AstCFunc* cfuncp) {
         getFTaskVertex(nodep)->cFuncp(cfuncp);
@@ -365,7 +368,10 @@ class TaskVisitor final : public VNVisitor {
     AstNode* m_insStmtp = nullptr;  // Where to insert statement
     bool m_inSensesp = false;  // Are we under a senitem?
     int m_modNCalls = 0;  // Incrementing func # for making symbols
+
+    // STATE - across all visitors
     DpiCFuncs m_dpiNames;  // Map of all created DPI functions
+    VDouble0 m_statInlines;  // Statistic tracking
 
     // METHODS
 
@@ -1454,6 +1460,7 @@ class TaskVisitor final : public VNVisitor {
             beginp = createNonInlinedFTask(nodep, namePrefix, outvscp, cnewp /*ref*/);
         } else {
             beginp = createInlinedFTask(nodep, namePrefix, outvscp);
+            ++m_statInlines;
         }
 
         if (VN_IS(nodep, New)) {
@@ -1606,7 +1613,7 @@ public:
         : m_statep{statep} {
         iterate(nodep);
     }
-    ~TaskVisitor() override = default;
+    ~TaskVisitor() { V3Stats::addStat("Optimizations, Functions inlined", m_statInlines); }
 };
 
 //######################################################################

test_regress/driver.py

@@ -2450,7 +2450,7 @@ class VlTest:
         if not match:
             self.error("File_grep: " + filename + ": Regexp not found: " + regexp)
             return None
-        if expvalue and str(expvalue) != match.group(1):
+        if expvalue is not None and str(expvalue) != match.group(1):
             self.error("File_grep: " + filename + ": Got='" + match.group(1) + "' Expected='" +
                        str(expvalue) + "' in regexp: '" + regexp + "'")
             return None
@@ -2472,7 +2472,7 @@ class VlTest:
                 return
             match = re.search(regexp, contents)
             if match:
-                if expvalue and str(expvalue) != match.group(1):
+                if expvalue is not None and str(expvalue) != match.group(1):
                     self.error("file_grep: " + filename + ": Got='" + match.group(1) +
                                "' Expected='" + str(expvalue) + "' in regexp: " + regexp)
                 return

test_regress/t/t_opt_inline_funcs.py

@@ -0,0 +1,18 @@
+#!/usr/bin/env python3
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2024 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.
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+import vltest_bootstrap
+
+test.scenarios('vlt')
+
+test.compile(verilator_flags2=['--stats'], verilator_make_gmake=False)
+
+test.file_grep(test.stats, r'Optimizations, Functions inlined\s+(\d+)', 2)
+
+test.passes()

test_regress/t/t_opt_inline_funcs.v

@@ -0,0 +1,21 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain, for
+// any use, without warranty, 2024 by Wilson Snyder.
+// SPDX-License-Identifier: CC0-1.0
+
+module t (/*AUTOARG*/);
+
+   function void allfin;
+      $write("*-* All Finished *-*\n");
+   endfunction
+
+   task done;
+      $finish;
+   endtask
+
+   initial begin
+      allfin();
+      done();
+   end
+endmodule

test_regress/t/t_opt_inline_funcs_no.py

@@ -0,0 +1,19 @@
+#!/usr/bin/env python3
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2024 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.
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+import vltest_bootstrap
+
+test.scenarios('vlt')
+test.top_filename = "t/t_opt_inline_funcs.v"
+
+test.compile(verilator_flags2=['--fno-inline-funcs', '--stats'], verilator_make_gmake=False)
+
+test.file_grep(test.stats, r'Optimizations, Functions inlined\s+(\d+)', 0)
+
+test.passes()