From b3ffa8b5f0bbd7038863826f8b20f0d73b93b43f Mon Sep 17 00:00:00 2001
From: TCMalloc Team <tcmalloc-eng@google.com>
Date: Fri, 17 Jul 2026 03:16:18 -0700
Subject: [PATCH] Add portability fixes for non-Linux platforms to tcmalloc
 internals.

PiperOrigin-RevId: 949467889
---
 tcmalloc/internal/cpu_utils.h | 22 ++++++++++++++++++++++
 tcmalloc/internal/sysinfo.h   | 17 ++++++++++++++++-
 2 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/tcmalloc/internal/cpu_utils.h b/tcmalloc/internal/cpu_utils.h
index ab76e4a4e..a6a2fab91 100644
--- a/tcmalloc/internal/cpu_utils.h
+++ b/tcmalloc/internal/cpu_utils.h
@@ -22,6 +22,20 @@
 #include "absl/base/attributes.h"
 #include "tcmalloc/internal/config.h"
 
+#if !defined(__linux__)
+// Stub types and macros for non-Linux platforms.
+typedef struct {
+  char dummy;
+} cpu_set_t;
+
+#define CPU_ALLOC_SIZE(x) 1
+#define CPU_ZERO_S(size, set)
+#define CPU_SET_S(cpu, size, set)
+#define CPU_ISSET_S(cpu, size, set) ((cpu) == 0)
+#define CPU_CLR_S(cpu, size, set)
+#define CPU_COUNT_S(size, set) 1
+#endif
+
 GOOGLE_MALLOC_SECTION_BEGIN
 namespace tcmalloc {
 namespace tcmalloc_internal {
@@ -57,14 +71,22 @@ class CpuSet {
   // successful. If returns false, please check the global 'errno' variable to
   // determine the specific error that occurred.
   [[nodiscard]] bool SetAffinity(pid_t pid) {
+#if defined(__linux__)
     return sched_setaffinity(pid, kCpuSetBytes, cpu_set_.data()) == 0;
+#else
+    return true;
+#endif
   }
 
   // Gets the CPU affinity of the process with the given pid. Return trues if
   // successful. If returns false, please check the global 'errno' variable to
   // determine the specific error that occurred.
   [[nodiscard]] bool GetAffinity(pid_t pid) {
+#if defined(__linux__)
     return sched_getaffinity(pid, kCpuSetBytes, cpu_set_.data()) == 0;
+#else
+    return true;
+#endif
   }
 
   const cpu_set_t* data() const { return cpu_set_.data(); }
diff --git a/tcmalloc/internal/sysinfo.h b/tcmalloc/internal/sysinfo.h
index a7aa9694f..93dfdb0ba 100644
--- a/tcmalloc/internal/sysinfo.h
+++ b/tcmalloc/internal/sysinfo.h
@@ -17,6 +17,9 @@
 
 #include <sched.h>
 #include <sys/types.h>
+#if !defined(__linux__) && __has_include(<unistd.h>)
+#include <unistd.h>
+#endif
 
 #include <cstddef>
 #include <optional>
@@ -25,7 +28,9 @@
 #include "absl/base/call_once.h"
 #include "absl/functional/function_ref.h"
 #include "tcmalloc/internal/config.h"
+#if __linux__
 #include "tcmalloc/internal/cpu_utils.h"
+#endif
 #include "tcmalloc/internal/logging.h"
 
 GOOGLE_MALLOC_SECTION_BEGIN
@@ -67,7 +72,17 @@ inline std::optional<int> NumCPUsMaybe() {
 
 #else  // __linux__
 
-inline std::optional<int> NumCPUsMaybe() { return std::nullopt; }
+inline std::optional<int> NumCPUsMaybe() {
+#if defined(_SC_NPROCESSORS_ONLN)
+  int n = static_cast<int>(sysconf(_SC_NPROCESSORS_ONLN));
+  if (n == -1) {
+    return std::nullopt;
+  }
+  return n;
+#else
+  return std::nullopt;
+#endif
+}
 
 #endif  // __linux__