Replace calls to system() with new run_process() helper.

src/CodeGen_Metal_Dev.cpp

@@ -883,16 +883,11 @@ vector<char> CodeGen_Metal_Dev::compile_to_src() {
         // Compile the Metal source to a metallib.
         string metalir = tmpfile + ".ir";
         string metallib = tmpfile + "lib";
-        string cmd = string(metal_compiler) + " -c -o " + metalir + " " + tmpfile;
-        debug(2) << "Running: " << cmd << "\n";
 
-        int ret = system(cmd.c_str());
+        int ret = run_process({metal_compiler, "-c", "-o", metalir, tmpfile});
         user_assert(ret == 0) << "Metal compiler set, but failed to compile Metal source to Metal IR.\n";
 
-        cmd = string(metal_linker) + " -o " + metallib + " " + metalir;
-        debug(2) << "Running: " << cmd << "\n";
-
-        ret = system(cmd.c_str());
+        ret = run_process({metal_linker, "-o", metallib, metalir});
         user_assert(ret == 0) << "Metal linker set, but failed to compile Metal IR to Metal library.\n";
 
         // Read the metallib into a buffer.

src/CodeGen_PTX_Dev.cpp

@@ -756,11 +756,8 @@ vector<char> CodeGen_PTX_Dev::compile_to_src() {
         f.write(buffer.data(), buffer.size());
         f.close();
 
-        string cmd = "ptxas --gpu-name " + mcpu_target() + " " + ptx.pathname() + " -o " + sass.pathname();
-        if (system(cmd.c_str()) == 0) {
-            cmd = "nvdisasm " + sass.pathname();
-            int ret = system(cmd.c_str());
-            (void)ret;  // Don't care if it fails
+        if (run_process({"ptxas", "--gpu-name", mcpu_target(), ptx.pathname(), "-o", sass.pathname()}) == 0) {
+            (void)run_process({"nvdisasm", sass.pathname()});  // Don't care if it fails
         }
 
         // Note: It works to embed the contents of the .sass file in

src/HexagonOffload.cpp

@@ -1101,11 +1101,8 @@ Buffer<uint8_t> compile_module_to_hexagon_shared_object(const Module &device_cod
         write_entire_file(input.pathname(), shared_object);
 
         debug(1) << "Signing tool: (" << signer << ")\n";
-        std::string cmd = signer + " " + input.pathname() + " " + output.pathname();
-        int result = system(cmd.c_str());
-        internal_assert(result == 0)
-            << "HL_HEXAGON_CODE_SIGNER failed: result = " << result
-            << " for cmd (" << cmd << ")";
+        int result = run_process({signer, input.pathname(), output.pathname()});
+        internal_assert(result == 0) << "HL_HEXAGON_CODE_SIGNER failed: result = " << result;
 
         shared_object = read_entire_file(output.pathname());
     }

src/Util.cpp

@@ -18,11 +18,16 @@
 
 #ifdef _MSC_VER
 #include <io.h>
+#include <process.h>  // For _spawnvp
 #else
 #include <cstdlib>
+#include <spawn.h>
 #include <sys/mman.h>  // For mmap
+#include <sys/wait.h>
 #include <unistd.h>
+extern char **environ;
 #endif
+
 #include <sys/stat.h>
 #include <sys/types.h>
 
@@ -31,16 +36,19 @@
 #include <linux/limits.h>  // For PATH_MAX
 #include <ucontext.h>      // For swapcontext
 #endif
+
 #if defined(_MSC_VER) && !defined(NOMINMAX)
 #define NOMINMAX
 #endif
+
 #ifdef _WIN32
 #include <Objbase.h>  // needed for CoCreateGuid
 #include <Shlobj.h>   // needed for SHGetFolderPath
 #include <windows.h>
 #else
 #include <dlfcn.h>
 #endif
+
 #ifdef __APPLE__
 #define CAN_GET_RUNNING_PROGRAM_NAME
 #include <mach-o/dyld.h>
@@ -497,6 +505,32 @@ void write_entire_file(const std::string &pathname, const void *source, size_t s
     f.close();
 }
 
+int run_process(std::vector<std::string> args) {
+    internal_assert(!args.empty()) << "run_process called with empty args\n";
+
+    std::vector<char *> argv;
+    argv.reserve(args.size() + 1);
+    for (auto &a : args) {
+        argv.push_back(a.data());
+    }
+    argv.push_back(nullptr);
+
+    debug(2) << "Running process: " << PrintSpan(args) << "\n";
+
+#ifdef _WIN32
+    // Wait for completion; return the child's exit code.
+    int rc = _spawnvp(_P_WAIT, argv[0], argv.data());
+    return (rc >= 0) ? rc : -1;
+#else
+    pid_t pid = 0;
+    int status = posix_spawnp(&pid, argv[0], nullptr, nullptr, argv.data(), environ);
+    if (status != 0 || waitpid(pid, &status, 0) == -1) {
+        return -1;
+    }
+    return WIFEXITED(status) ? WEXITSTATUS(status) : -1;
+#endif
+}
+
 bool add_would_overflow(int bits, int64_t a, int64_t b) {
     int64_t max_val = 0x7fffffffffffffffLL >> (64 - bits);
     int64_t min_val = -max_val - 1;

src/Util.h

@@ -371,6 +371,13 @@ class TemporaryFile final {
     TemporaryFile &operator=(TemporaryFile &&) = delete;
 };
 
+/** Run an executable with the given arguments without going through
+ * the shell. The first element of args should be the program name/path.
+ * If a name without a path-separator is given, it will be searched for
+ * in the PATH. Returns the exit code of the process, or -1 if the process
+ * could not be started. */
+int run_process(std::vector<std::string> args);
+
 /** Routines to test if math would overflow for signed integers with
  * the given number of bits. */
 // @{