[bugpoint] Increase the default memory limit for subprocesses to 300MB.

Summary:
Currently shared library builds (BUILD_SHARED_LIBS=ON in cmake) fail three
bugpoint tests (BugPoint/remove_arguments_test.ll,
BugPoint/crash-narrowfunctiontest.ll, and BugPoint/metadata.ll).

If I run the bugpoint commands that llvm-lit runs with without -silence-passes
I see errors such as this:
    opt: error while loading shared libraries: libLLVMSystemZInfo.so: failed to
    map segment from shared object: Cannot allocate memory

It seems that the increased size of the binaries in a shared library build is
causing the subprocess to exceed the 100MB memory limit. This patch therefore
increases the default limit to a level at which these tests pass.

Reviewers: dsanders

Reviewed By: dsanders

CC: llvm-commits, rafael

Differential Revision: http://llvm-reviews.chandlerc.com/D2013

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@193420 91177308-0d34-0410-b5e6-96231b3b80d8

tools/bugpoint/bugpoint.cpp

@@ -49,8 +49,8 @@ TimeoutValue("timeout", cl::init(300), cl::value_desc("seconds"),
 
 static cl::opt<int>
 MemoryLimit("mlimit", cl::init(-1), cl::value_desc("MBytes"),
-             cl::desc("Maximum amount of memory to use. 0 disables check."
-                      " Defaults to 100MB (800MB under valgrind)."));
+            cl::desc("Maximum amount of memory to use. 0 disables check."
+                     " Defaults to 300MB (800MB under valgrind)."));
 
 static cl::opt<bool>
 UseValgrind("enable-valgrind",
@@ -152,7 +152,7 @@ int main(int argc, char **argv) {
     if (sys::RunningOnValgrind() || UseValgrind)
       MemoryLimit = 800;
     else
-      MemoryLimit = 100;
+      MemoryLimit = 300;
   }
 
   BugDriver D(argv[0], FindBugs, TimeoutValue, MemoryLimit,