diff --git a/compiler-rt/lib/memprof/memprof_interface_internal.h b/compiler-rt/lib/memprof/memprof_interface_internal.h
--- a/compiler-rt/lib/memprof/memprof_interface_internal.h
+++ b/compiler-rt/lib/memprof/memprof_interface_internal.h
@@ -46,6 +46,9 @@
 SANITIZER_INTERFACE_ATTRIBUTE
 extern uptr __memprof_shadow_memory_dynamic_address;
 
+SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE extern char
+    __memprof_profile_filename[1];
+
 SANITIZER_INTERFACE_ATTRIBUTE void __memprof_load(uptr p);
 SANITIZER_INTERFACE_ATTRIBUTE void __memprof_store(uptr p);
 
diff --git a/compiler-rt/lib/memprof/memprof_rtl.cpp b/compiler-rt/lib/memprof/memprof_rtl.cpp
--- a/compiler-rt/lib/memprof/memprof_rtl.cpp
+++ b/compiler-rt/lib/memprof/memprof_rtl.cpp
@@ -27,6 +27,9 @@
 
 uptr __memprof_shadow_memory_dynamic_address; // Global interface symbol.
 
+// Allow the user to specify a profile output file via the binary.
+SANITIZER_WEAK_ATTRIBUTE char __memprof_profile_filename[1] = {0};
+
 namespace __memprof {
 
 static void MemprofDie() {
@@ -174,7 +177,12 @@
   AddDieCallback(MemprofDie);
   SetCheckFailedCallback(MemprofCheckFailed);
 
-  __sanitizer_set_report_path(common_flags()->log_path);
+  // Use profile name specified via the binary itself if it exists, and hasn't
+  // been overrriden by a flag at runtime.
+  if (__memprof_profile_filename[0] != 0 && !common_flags()->log_path)
+    __sanitizer_set_report_path(__memprof_profile_filename);
+  else
+    __sanitizer_set_report_path(common_flags()->log_path);
 
   __sanitizer::InitializePlatformEarly();
 
diff --git a/compiler-rt/lib/memprof/weak_symbols.txt b/compiler-rt/lib/memprof/weak_symbols.txt
--- a/compiler-rt/lib/memprof/weak_symbols.txt
+++ b/compiler-rt/lib/memprof/weak_symbols.txt
@@ -1 +1 @@
-___memprof_default_options
+___memprof_default_options __memprof_profile_filename
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_file.cpp b/compiler-rt/lib/sanitizer_common/sanitizer_file.cpp
--- a/compiler-rt/lib/sanitizer_common/sanitizer_file.cpp
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_file.cpp
@@ -69,24 +69,23 @@
 }
 
 void ReportFile::SetReportPath(const char *path) {
-  if (!path)
-    return;
-  uptr len = internal_strlen(path);
-  if (len > sizeof(path_prefix) - 100) {
-    Report("ERROR: Path is too long: %c%c%c%c%c%c%c%c...\n",
-           path[0], path[1], path[2], path[3],
-           path[4], path[5], path[6], path[7]);
-    Die();
+  if (path) {
+    uptr len = internal_strlen(path);
+    if (len > sizeof(path_prefix) - 100) {
+      Report("ERROR: Path is too long: %c%c%c%c%c%c%c%c...\n", path[0], path[1],
+             path[2], path[3], path[4], path[5], path[6], path[7]);
+      Die();
+    }
   }
 
   SpinMutexLock l(mu);
   if (fd != kStdoutFd && fd != kStderrFd && fd != kInvalidFd)
     CloseFile(fd);
   fd = kInvalidFd;
-  if (internal_strcmp(path, "stdout") == 0) {
-    fd = kStdoutFd;
-  } else if (internal_strcmp(path, "stderr") == 0) {
+  if (!path || internal_strcmp(path, "stderr") == 0) {
     fd = kStderrFd;
+  } else if (internal_strcmp(path, "stdout") == 0) {
+    fd = kStdoutFd;
   } else {
     internal_snprintf(path_prefix, kMaxPathLength, "%s", path);
   }
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_flags.inc b/compiler-rt/lib/sanitizer_common/sanitizer_flags.inc
--- a/compiler-rt/lib/sanitizer_common/sanitizer_flags.inc
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_flags.inc
@@ -47,9 +47,9 @@
 COMMON_FLAG(int, malloc_context_size, 1,
             "Max number of stack frames kept for each allocation/deallocation.")
 COMMON_FLAG(
-    const char *, log_path, "stderr",
+    const char *, log_path, nullptr,
     "Write logs to \"log_path.pid\". The special values are \"stdout\" and "
-    "\"stderr\". The default is \"stderr\".")
+    "\"stderr\". If unspecified, defaults to \"stderr\".")
 COMMON_FLAG(
     bool, log_exe_name, false,
     "Mention name of executable when reporting error and "
diff --git a/compiler-rt/test/memprof/TestCases/atexit_stats.cpp b/compiler-rt/test/memprof/TestCases/atexit_stats.cpp
--- a/compiler-rt/test/memprof/TestCases/atexit_stats.cpp
+++ b/compiler-rt/test/memprof/TestCases/atexit_stats.cpp
@@ -1,8 +1,8 @@
 // Check atexit option.
 
 // RUN: %clangxx_memprof -O0 %s -o %t
-// RUN: %env_memprof_opts=atexit=1 %run %t 2>&1 | FileCheck %s
-// RUN: %env_memprof_opts=atexit=0 %run %t 2>&1 | FileCheck %s --check-prefix=NOATEXIT
+// RUN: %env_memprof_opts=log_path=stderr:atexit=1 %run %t 2>&1 | FileCheck %s
+// RUN: %env_memprof_opts=log_path=stderr:atexit=0 %run %t 2>&1 | FileCheck %s --check-prefix=NOATEXIT
 
 // CHECK: MemProfiler exit stats:
 // CHECK: Stats: {{[0-9]+}}M malloced ({{[0-9]+}}M for overhead) by {{[0-9]+}} calls
diff --git a/compiler-rt/test/memprof/TestCases/dump_process_map.cpp b/compiler-rt/test/memprof/TestCases/dump_process_map.cpp
--- a/compiler-rt/test/memprof/TestCases/dump_process_map.cpp
+++ b/compiler-rt/test/memprof/TestCases/dump_process_map.cpp
@@ -1,8 +1,8 @@
 // Check dump_process_map option.
 
 // RUN: %clangxx_memprof -O0 %s -o %t
-// RUN: %env_memprof_opts=dump_process_map=1 %run %t 2>&1 | FileCheck %s
-// RUN: %env_memprof_opts=dump_process_map=0 %run %t 2>&1 | FileCheck %s --check-prefix=NOMAP
+// RUN: %env_memprof_opts=log_path=stderr:dump_process_map=1 %run %t 2>&1 | FileCheck %s
+// RUN: %env_memprof_opts=log_path=stderr:dump_process_map=0 %run %t 2>&1 | FileCheck %s --check-prefix=NOMAP
 
 // CHECK: Process memory map follows:
 // CHECK: dump_process_map.cpp.tmp
diff --git a/compiler-rt/test/memprof/TestCases/log_path_test.cpp b/compiler-rt/test/memprof/TestCases/log_path_test.cpp
--- a/compiler-rt/test/memprof/TestCases/log_path_test.cpp
+++ b/compiler-rt/test/memprof/TestCases/log_path_test.cpp
@@ -3,8 +3,8 @@
 //
 // RUN: %clangxx_memprof  %s -o %t
 
-// Regular run.
-// RUN: %run %t 2> %t.out
+// stderr log_path
+// RUN: %env_memprof_opts=log_path=stderr %run %t 2> %t.out
 // RUN: FileCheck %s --check-prefix=CHECK-GOOD < %t.out
 
 // Good log_path.
@@ -21,6 +21,24 @@
 // RUN:   not %run %t 2> %t.out
 // RUN: FileCheck %s --check-prefix=CHECK-LONG < %t.out
 
+// Specifying the log name via the __memprof_profile_filename variable.
+// RUN: %clangxx_memprof  %s -o %t -DPROFILE_NAME_VAR="%t.log2"
+// RUN: rm -f %t.log2.*
+// RUN: %run %t 2> %t.out
+// RUN: FileCheck %s --check-prefix=CHECK-GOOD < %t.log2.*
+
+// Check that the log_path option overrides the log name set via the
+// __memprof_profile_filename variable.
+// RUN: rm -f %t.log.*
+// RUN: %env_memprof_opts=log_path=%t.log %run %t 2> %t.out
+// RUN: FileCheck %s --check-prefix=CHECK-GOOD < %t.log.*
+
+#ifdef PROFILE_NAME_VAR
+#define xstr(s) str(s)
+#define str(s) #s
+char __memprof_profile_filename[] = xstr(PROFILE_NAME_VAR);
+#endif
+
 #include <stdlib.h>
 #include <string.h>
 int main(int argc, char **argv) {
diff --git a/compiler-rt/test/memprof/TestCases/malloc-size-too-big.cpp b/compiler-rt/test/memprof/TestCases/malloc-size-too-big.cpp
--- a/compiler-rt/test/memprof/TestCases/malloc-size-too-big.cpp
+++ b/compiler-rt/test/memprof/TestCases/malloc-size-too-big.cpp
@@ -1,8 +1,8 @@
 // RUN: %clangxx_memprof -O0 %s -o %t
-// RUN: %env_memprof_opts=allocator_may_return_null=0 not %run %t 2>&1 | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-SUMMARY
-// RUN: %env_memprof_opts=allocator_may_return_null=1 %run %t 2>&1 | FileCheck %s --check-prefix=CHECK-NULL
+// RUN: %env_memprof_opts=log_path=stderr:allocator_may_return_null=0 not %run %t 2>&1 | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-SUMMARY
+// RUN: %env_memprof_opts=log_path=stderr:allocator_may_return_null=1 %run %t 2>&1 | FileCheck %s --check-prefix=CHECK-NULL
 // Test print_summary
-// RUN: %env_memprof_opts=allocator_may_return_null=0:print_summary=0 not %run %t 2>&1 | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-NOSUMMARY
+// RUN: %env_memprof_opts=log_path=stderr:allocator_may_return_null=0:print_summary=0 not %run %t 2>&1 | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-NOSUMMARY
 
 #include <stdio.h>
 #include <stdlib.h>
diff --git a/compiler-rt/test/memprof/TestCases/mem_info_cache_entries.cpp b/compiler-rt/test/memprof/TestCases/mem_info_cache_entries.cpp
--- a/compiler-rt/test/memprof/TestCases/mem_info_cache_entries.cpp
+++ b/compiler-rt/test/memprof/TestCases/mem_info_cache_entries.cpp
@@ -1,6 +1,6 @@
 // Check mem_info_cache_entries option.
 
-// RUN: %clangxx_memprof -O0 %s -o %t && %env_memprof_opts=mem_info_cache_entries=15:print_mem_info_cache_miss_rate=1:print_mem_info_cache_miss_rate_details=1 %run %t 2>&1 | FileCheck %s
+// RUN: %clangxx_memprof -O0 %s -o %t && %env_memprof_opts=log_path=stderr:mem_info_cache_entries=15:print_mem_info_cache_miss_rate=1:print_mem_info_cache_miss_rate_details=1 %run %t 2>&1 | FileCheck %s
 
 // CHECK: Set 14 miss rate: 0 / {{.*}} = 0.00%
 // CHECK-NOT: Set
diff --git a/compiler-rt/test/memprof/TestCases/print_miss_rate.cpp b/compiler-rt/test/memprof/TestCases/print_miss_rate.cpp
--- a/compiler-rt/test/memprof/TestCases/print_miss_rate.cpp
+++ b/compiler-rt/test/memprof/TestCases/print_miss_rate.cpp
@@ -2,8 +2,8 @@
 // print_mem_info_cache_miss_rate_details options.
 
 // RUN: %clangxx_memprof -O0 %s -o %t
-// RUN: %env_memprof_opts=print_mem_info_cache_miss_rate=1 %run %t 2>&1 | FileCheck %s
-// RUN: %env_memprof_opts=print_mem_info_cache_miss_rate=1:print_mem_info_cache_miss_rate_details=1 %run %t 2>&1 | FileCheck %s --check-prefix=DETAILS
+// RUN: %env_memprof_opts=log_path=stderr:print_mem_info_cache_miss_rate=1 %run %t 2>&1 | FileCheck %s
+// RUN: %env_memprof_opts=log_path=stderr:print_mem_info_cache_miss_rate=1:print_mem_info_cache_miss_rate_details=1 %run %t 2>&1 | FileCheck %s --check-prefix=DETAILS
 
 // CHECK: Overall miss rate: 0 / {{.*}} = 0.00%
 // DETAILS: Set 0 miss rate: 0 / {{.*}} = 0.00%
diff --git a/compiler-rt/test/memprof/TestCases/stress_dtls.c b/compiler-rt/test/memprof/TestCases/stress_dtls.c
--- a/compiler-rt/test/memprof/TestCases/stress_dtls.c
+++ b/compiler-rt/test/memprof/TestCases/stress_dtls.c
@@ -7,9 +7,9 @@
 // RUN: %clangxx_memprof %s -ldl -pthread -o %t
 // RUN: %run %t 0 3
 // RUN: %run %t 2 3
-// RUN: %env_memprof_opts=verbosity=2 %run %t 10 2 2>&1 | FileCheck %s
-// RUN: %env_memprof_opts=verbosity=2:intercept_tls_get_addr=1 %run %t 10 2 2>&1 | FileCheck %s
-// RUN: %env_memprof_opts=verbosity=2:intercept_tls_get_addr=0 %run %t 10 2 2>&1 | FileCheck %s --check-prefix=CHECK0
+// RUN: %env_memprof_opts=log_path=stderr:verbosity=2 %run %t 10 2 2>&1 | FileCheck %s
+// RUN: %env_memprof_opts=log_path=stderr:verbosity=2:intercept_tls_get_addr=1 %run %t 10 2 2>&1 | FileCheck %s
+// RUN: %env_memprof_opts=log_path=stderr:verbosity=2:intercept_tls_get_addr=0 %run %t 10 2 2>&1 | FileCheck %s --check-prefix=CHECK0
 // CHECK: __tls_get_addr
 // CHECK: Creating thread 0
 // CHECK: __tls_get_addr
diff --git a/compiler-rt/test/memprof/TestCases/test_malloc_load_store.c b/compiler-rt/test/memprof/TestCases/test_malloc_load_store.c
--- a/compiler-rt/test/memprof/TestCases/test_malloc_load_store.c
+++ b/compiler-rt/test/memprof/TestCases/test_malloc_load_store.c
@@ -3,10 +3,10 @@
 // before exit.
 
 // RUN: %clangxx_memprof -O0 %s -o %t
-// RUN: %env_memprof_opts= %run %t 2>&1 | FileCheck %s
+// RUN: %env_memprof_opts=log_path=stderr %run %t 2>&1 | FileCheck %s
 
 // RUN: %clangxx_memprof -DFREE -O0 %s -o %t
-// RUN: %env_memprof_opts= %run %t 2>&1 | FileCheck %s
+// RUN: %env_memprof_opts=log_path=stderr %run %t 2>&1 | FileCheck %s
 
 // This is actually:
 //  Memory allocation stack id = STACKID
diff --git a/compiler-rt/test/memprof/TestCases/test_memintrin.cpp b/compiler-rt/test/memprof/TestCases/test_memintrin.cpp
--- a/compiler-rt/test/memprof/TestCases/test_memintrin.cpp
+++ b/compiler-rt/test/memprof/TestCases/test_memintrin.cpp
@@ -1,6 +1,6 @@
 // Check profile with calls to memory intrinsics.
 
-// RUN: %clangxx_memprof -O0 %s -o %t && %run %t 2>&1 | FileCheck %s
+// RUN: %clangxx_memprof -O0 %s -o %t && %env_memprof_opts=log_path=stderr %run %t 2>&1 | FileCheck %s
 
 // This is actually:
 //  Memory allocation stack id = STACKIDP
diff --git a/compiler-rt/test/memprof/TestCases/test_new_load_store.cpp b/compiler-rt/test/memprof/TestCases/test_new_load_store.cpp
--- a/compiler-rt/test/memprof/TestCases/test_new_load_store.cpp
+++ b/compiler-rt/test/memprof/TestCases/test_new_load_store.cpp
@@ -3,14 +3,14 @@
 // before exit.
 
 // RUN: %clangxx_memprof -O0 %s -o %t
-// RUN: %env_memprof_opts= %run %t 2>&1 | FileCheck %s
+// RUN: %env_memprof_opts=log_path=stderr %run %t 2>&1 | FileCheck %s
 
 // RUN: %clangxx_memprof -DFREE -O0 %s -o %t
-// RUN: %env_memprof_opts= %run %t 2>&1 | FileCheck %s
+// RUN: %env_memprof_opts=log_path=stderr %run %t 2>&1 | FileCheck %s
 
 // Try again with callbacks instead of inline sequences
 // RUN: %clangxx_memprof -mllvm -memprof-use-callbacks -O0 %s -o %t
-// RUN: %env_memprof_opts= %run %t 2>&1 | FileCheck %s
+// RUN: %env_memprof_opts=log_path=stderr %run %t 2>&1 | FileCheck %s
 
 // This is actually:
 //  Memory allocation stack id = STACKID
diff --git a/compiler-rt/test/memprof/TestCases/test_terse.cpp b/compiler-rt/test/memprof/TestCases/test_terse.cpp
--- a/compiler-rt/test/memprof/TestCases/test_terse.cpp
+++ b/compiler-rt/test/memprof/TestCases/test_terse.cpp
@@ -3,10 +3,10 @@
 // deallocated before exit.
 
 // RUN: %clangxx_memprof -O0 %s -o %t
-// RUN: %env_memprof_opts=print_terse=1 %run %t 2>&1 | FileCheck %s
+// RUN: %env_memprof_opts=log_path=stderr:print_terse=1 %run %t 2>&1 | FileCheck %s
 
 // RUN: %clangxx_memprof -DFREE -O0 %s -o %t
-// RUN: %env_memprof_opts=print_terse=1 %run %t 2>&1 | FileCheck %s
+// RUN: %env_memprof_opts=log_path=stderr:print_terse=1 %run %t 2>&1 | FileCheck %s
 
 // CHECK: MIB:[[STACKID:[0-9]+]]/1/40.00/40/40/20.00/20/20/[[AVELIFETIME:[0-9]+]].00/[[AVELIFETIME]]/[[AVELIFETIME]]/0/0/0/0
 // CHECK: Stack for id [[STACKID]]:
diff --git a/compiler-rt/test/memprof/TestCases/unaligned_loads_and_stores.cpp b/compiler-rt/test/memprof/TestCases/unaligned_loads_and_stores.cpp
--- a/compiler-rt/test/memprof/TestCases/unaligned_loads_and_stores.cpp
+++ b/compiler-rt/test/memprof/TestCases/unaligned_loads_and_stores.cpp
@@ -1,4 +1,4 @@
-// RUN: %clangxx_memprof -O0 %s -o %t && %run %t 2>&1 | FileCheck %s
+// RUN: %clangxx_memprof -O0 %s -o %t && %env_memprof_opts=log_path=stderr %run %t 2>&1 | FileCheck %s
 
 // This is actually:
 //  Memory allocation stack id = STACKID