tests: Stop "using namespace std" in unittest/.

These are the historical "unit test"s, which aren't really unit tests,
they're actually complete builds of gem5 with main functions which run a
fairly specific test instead of a simulation. They test a single unit,
but they do it with all the other units in place and potentially
participating in the test.

Change-Id: Ib0ea68f26091a79992396d932627e4ce180f7825
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/39565
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Maintainer: Giacomo Travaglini <giacomo.travaglini@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>

src/unittest/cprintftime.cc

@@ -36,8 +36,6 @@
 
 #include "base/cprintf.hh"
 
-using namespace std;
-
 volatile int stop = false;
 
 void
@@ -56,14 +54,14 @@ do_test(int seconds)
 int
 main()
 {
-    stringstream result;
+    std::stringstream result;
     int iterations = 0;
 
     signal(SIGALRM, handle_alarm);
 
     do_test(10);
     while (!stop) {
-        stringstream result;
+        std::stringstream result;
         ccprintf(result,
                  "this is a %s of %d iterations %3.2f %p\n",
                  "test", iterations, 51.934, &result);

src/unittest/nmtest.cc

@@ -34,8 +34,6 @@
 #include "base/logging.hh"
 #include "base/str.hh"
 
-using namespace std;
-
 int
 main(int argc, char *argv[])
 {
@@ -50,7 +48,7 @@ main(int argc, char *argv[])
         for (const Loader::Symbol &symbol: obj->symtab())
             cprintf("%#x %s\n", symbol.address, symbol.name);
     } else {
-        string symbol = argv[2];
+        std::string symbol = argv[2];
         Addr address;
 
         if (symbol[0] == '0' && symbol[1] == 'x') {

src/unittest/stattest.cc

@@ -50,7 +50,6 @@ const char *m5MainCommands[] = {
     0 // sentinel is required
 };
 
-using namespace std;
 using namespace Stats;
 
 double testfunc();

src/unittest/symtest.cc

@@ -31,14 +31,13 @@
 #include "base/loader/symtab.hh"
 #include "base/str.hh"
 
-using namespace std;
-
 void usage(const char *progname);
 
 void
 usage(const char *progname)
 {
-    cout << "Usage: " << progname << " <symbol file> <symbol>" << endl;
+    std::cout << "Usage: " << progname << " <symbol file> <symbol>"
+        << std::endl;
 
     exit(1);
 }
@@ -52,29 +51,31 @@ main(int argc, char *argv[])
         usage(argv[0]);
 
     if (!symtab.load(argv[1])) {
-        cout << "could not load symbol file: " << argv[1] << endl;
+        std::cout << "could not load symbol file: " << argv[1] << std::endl;
         exit(1);
     }
 
-    string symbol = argv[2];
+    std::string symbol = argv[2];
     Addr address;
 
     if (!to_number(symbol, address)) {
         auto it = symtab.find(symbol);
         if (it == symtab.end()) {
-            cout << "could not find symbol: " << symbol << endl;
+            std::cout << "could not find symbol: " << symbol << std::endl;
             exit(1);
         }
 
-        cout << symbol << " -> " << "0x" << hex << it->address << endl;
+        std::cout << symbol << " -> " << "0x" << std::hex << it->address <<
+            std::endl;
     } else {
         auto it = symtab.find(address);
         if (it == symtab.end()) {
-            cout << "could not find address: " << address << endl;
+            std::cout << "could not find address: " << address << std::endl;
             exit(1);
         }
 
-        cout << "0x" << hex << address << " -> " << it->name << endl;
+        std::cout << "0x" << std::hex << address << " -> " << it->name <<
+            std::endl;
     }
 
     return 0;