[Support] Implement getMainExecutable on Solaris

Many `flang` tests currently `FAIL` on Solaris because the module files
aren't found.  I could trace this to `sys::fs::getMainExecutable` not being
implemented.

This patch does this and fixes all affected `flang` tests.

Tested on `amd64-pc-solaris2.11`.

Differential Revision: https://reviews.llvm.org/D109374

diff --git a/llvm/lib/Support/Unix/Path.inc b/llvm/lib/Support/Unix/Path.inc
index c37b3a5..33c6259 100644 (file)
--- a/llvm/lib/Support/Unix/Path.inc
+++ b/llvm/lib/Support/Unix/Path.inc
@@ -125,7 +125,8 @@ const file_t kInvalidFile = -1;
 
 #if defined(__FreeBSD__) || defined(__NetBSD__) || defined(__OpenBSD__) ||     \
     defined(__minix) || defined(__FreeBSD_kernel__) || defined(__linux__) ||   \
-    defined(__CYGWIN__) || defined(__DragonFly__) || defined(_AIX) || defined(__GNU__)
+    defined(__CYGWIN__) || defined(__DragonFly__) || defined(_AIX) || defined(__GNU__) || \
+    (defined(__sun__) && defined(__svr4__))
 static int
 test_dir(char ret[PATH_MAX], const char *dir, const char *bin)
 {
@@ -283,6 +284,20 @@ std::string getMainExecutable(const char *argv0, void *MainAddr) {
   // Fall back to the classical detection.
   if (getprogpath(exe_path, argv0))
     return exe_path;
+#elif defined(__sun__) && defined(__svr4__)
+  char exe_path[PATH_MAX];
+  const char *aPath = "/proc/self/execname";
+  if (sys::fs::exists(aPath)) {
+    int fd = open(aPath, O_RDONLY);
+    if (fd == -1)
+      return "";
+    if (read(fd, exe_path, sizeof(exe_path)) < 0)
+      return "";
+    return exe_path;
+  }
+  // Fall back to the classical detection.
+  if (getprogpath(exe_path, argv0) != NULL)
+    return exe_path;
 #elif defined(__MVS__)
   int token = 0;
   W_PSPROC buf;