From 840970e8f72b8352f09901fe29e7eaf5204aedb9 Mon Sep 17 00:00:00 2001
From: Wilson Snyder <wsnyder@wsnyder.org>
Date: Sat, 30 Mar 2024 11:54:29 -0400
Subject: [PATCH] Internals: Add VL_MT_SAFE flags

---
 include/verilatedos.h   | 14 +++++++-------
 include/verilatedos_c.h | 12 +++++++-----
 2 files changed, 14 insertions(+), 12 deletions(-)

diff --git a/include/verilatedos.h b/include/verilatedos.h
index 2bbfbb69a..e4e2baab1 100644
--- a/include/verilatedos.h
+++ b/include/verilatedos.h
@@ -616,35 +616,35 @@ static inline double VL_ROUND(double n) {
 
 namespace VlOs {
 
-extern uint64_t memUsageBytes();  ///< Return memory usage in bytes, or 0 if not implemented
+extern uint64_t memUsageBytes() VL_MT_SAFE;  ///< Return memory usage in bytes, or 0 if unknown
 
 // Internal: Record CPU time, starting point on construction, and current delta from that
 class DeltaCpuTime final {
     double m_start{};  // Time constructed at
-    static double gettime();
+    static double gettime() VL_MT_SAFE;
 
 public:
     // Construct, and if startit is true, start() timer
     explicit DeltaCpuTime(bool startit) {
         if (startit) start();
     }
-    void start() { m_start = gettime(); }  // Start timer; record current time
-    double deltaTime() const {  // Return time between now and start()
+    void start() VL_MT_SAFE { m_start = gettime(); }  // Start timer; record current time
+    double deltaTime() const VL_MT_SAFE {  // Return time between now and start()
         return (m_start == 0.0) ? 0.0 : gettime() - m_start;
     }
 };
 // Internal: Record wall time, starting point on construction, and current delta from that
 class DeltaWallTime final {
     double m_start{};  // Time constructed at
-    static double gettime();
+    static double gettime() VL_MT_SAFE;
 
 public:
     // Construct, and if startit is true, start() timer
     explicit DeltaWallTime(bool startit) {
         if (startit) start();
     }
-    void start() { m_start = gettime(); }  // Start timer; record current time
-    double deltaTime() const {  // Return time between now and start()
+    void start() VL_MT_SAFE { m_start = gettime(); }  // Start timer; record current time
+    double deltaTime() const VL_MT_SAFE {  // Return time between now and start()
         return (m_start == 0.0) ? 0.0 : gettime() - m_start;
     }
 };
diff --git a/include/verilatedos_c.h b/include/verilatedos_c.h
index 2178984f4..dc7778e34 100644
--- a/include/verilatedos_c.h
+++ b/include/verilatedos_c.h
@@ -38,7 +38,7 @@ namespace VlOs {
 //=========================================================================
 // VlOs::VlGetCpuTime/VlGetWallTime implementation
 
-double DeltaCpuTime::gettime() {
+double DeltaCpuTime::gettime() VL_MT_SAFE {
 #if defined(_WIN32) || defined(__MINGW32__)
     FILETIME lpCreationTime, lpExitTime, lpKernelTime, lpUserTime;
     if (0
@@ -51,11 +51,12 @@ double DeltaCpuTime::gettime() {
 #else
     // NOLINTNEXTLINE(cppcoreguidelines-pro-type-member-init)
     timespec ts;
-    if (0 != clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &ts)) return ts.tv_sec + ts.tv_nsec * 1e-9;
+    if (0 != clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &ts))  // MT-Safe
+        return ts.tv_sec + ts.tv_nsec * 1e-9;
 #endif
     return 0.0;
 }
-double DeltaWallTime::gettime() {
+double DeltaWallTime::gettime() VL_MT_SAFE {
 #if defined(_WIN32) || defined(__MINGW32__)
     FILETIME ft;  // contains number of 0.1us intervals since the beginning of 1601 UTC.
     GetSystemTimeAsFileTime(&ft);
@@ -65,7 +66,8 @@ double DeltaWallTime::gettime() {
 #else
     // NOLINTNEXTLINE(cppcoreguidelines-pro-type-member-init)
     timespec ts;
-    if (0 == clock_gettime(CLOCK_MONOTONIC, &ts)) return ts.tv_sec + ts.tv_nsec * 1e-9;
+    if (0 == clock_gettime(CLOCK_MONOTONIC, &ts))  // MT-Safe
+        return ts.tv_sec + ts.tv_nsec * 1e-9;
     return 0.0;
 #endif
 }
@@ -73,7 +75,7 @@ double DeltaWallTime::gettime() {
 //=========================================================================
 // VlOs::memUsageBytes implementation
 
-uint64_t memUsageBytes() {
+uint64_t memUsageBytes() VL_MT_SAFE {
 #if defined(_WIN32) || defined(__MINGW32__)
     const HANDLE process = GetCurrentProcess();
     PROCESS_MEMORY_COUNTERS pmc;