[TestMiBreak] Print a formatted string via printf in the test case.

[sivachandra]

Summary

If the string is not formatted, these can happen when compiled with GCC:

1. If it is a null string "", then GCC completely removes the call to

printf even with -O0.

2. If the string is a single character string, say "\n" for example,

then GCC replaces the call to printf with a call to putchar.

3. If the string length is greater than 1, but is not formatted, then

GCC replaces the call to printf with a call to puts.

All the above will fail the test as we want a breakpoint on "printf" to
hit.

test/tools/lldb-mi/breakpoint/TestMiBreak.py

 """
 Test lldb-mi -break-xxx commands.
 """
 
 import lldbmi_testcase
 from lldbtest import *
 import unittest2
 
 class MiBreakTestCase(lldbmi_testcase.MiTestCaseBase):
 
     mydir = TestBase.compute_mydir(__file__)
 
     @lldbmi_test
     @expectedFailureWindows("llvm.org/pr22274: need a pexpect replacement for windows")
     @skipIfFreeBSD # llvm.org/pr22411: Failure presumably due to known thread races
-    @expectedFailureGcc #xfail to get buildbot green, test failed with gcc4.8.2
     def test_lldbmi_break_insert_function_pending(self):
         """Test that 'lldb-mi --interpreter' works for pending function breakpoints."""
 
         self.spawnLldbMi(args = None)
 
         self.runCmd("-file-exec-and-symbols %s" % self.myexe)
         self.expect("\^done")
 
         self.runCmd("-break-insert -f printf")
         self.expect("\^done,bkpt={number=\"1\"")
 
         self.runCmd("-exec-run")
         self.expect("\^running")
         self.expect("\*stopped,reason=\"breakpoint-hit\"")
 
     @lldbmi_test
     @expectedFailureWindows("llvm.org/pr22274: need a pexpect replacement for windows")
     @skipIfFreeBSD # llvm.org/pr22411: Failure presumably due to known thread races
-    @expectedFailureGcc #xfail to get buildbot green, test failed with gcc4.8.2
     def test_lldbmi_break_insert_function(self):
         """Test that 'lldb-mi --interpreter' works for function breakpoints."""
 
         self.spawnLldbMi(args = None)
 
         self.runCmd("-file-exec-and-symbols %s" % self.myexe)
         self.expect("\^done")
 
def test_lldbmi_break_insert_file_line_pending(self):
 
         self.runCmd("-exec-run")
         self.expect("\^running")
         self.expect("\*stopped,reason=\"breakpoint-hit\"")
 
     @lldbmi_test
     @expectedFailureWindows("llvm.org/pr22274: need a pexpect replacement for windows")
     @skipIfFreeBSD # llvm.org/pr22411: Failure presumably due to known thread races
-    @expectedFailureGcc #xfail to get buildbot green, test failed with gcc4.8.2
     def test_lldbmi_break_insert_file_line(self):
         """Test that 'lldb-mi --interpreter' works for file:line breakpoints."""
 
         self.spawnLldbMi(args = None)
 
         self.runCmd("-file-exec-and-symbols %s" % self.myexe)
         self.expect("\^done")
 

test/tools/lldb-mi/breakpoint/main.cpp

 //===-- main.cpp ------------------------------------------------*- C++ -*-===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 
 #include <cstdio>
 
 int
 main(int argc, char const *argv[])
 {
-    printf("");
+    printf("Print a formatted string so that GCC does not optimize this printf call: %s\n", argv[0]);
     return 0; // BP_return
 }