diff --git a/compiler-rt/lib/memprof/memprof_flags.inc b/compiler-rt/lib/memprof/memprof_flags.inc
--- a/compiler-rt/lib/memprof/memprof_flags.inc
+++ b/compiler-rt/lib/memprof/memprof_flags.inc
@@ -35,7 +35,7 @@
              "realloc(p, 0) is equivalent to free(p) by default (Same as the "
              "POSIX standard). If set to false, realloc(p, 0) will return a "
              "pointer to an allocated space which can not be used.")
-MEMPROF_FLAG(bool, print_text, true,
+MEMPROF_FLAG(bool, print_text, false,
   "If set, prints the heap profile in text format. Else use the raw binary serialization format.")
 MEMPROF_FLAG(bool, print_terse, false,
              "If set, prints memory profile in a terse format. Only applicable if print_text = true.")
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=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
+// RUN: %env_memprof_opts=print_text=true:log_path=stderr:atexit=1 %run %t 2>&1 | FileCheck %s
+// RUN: %env_memprof_opts=print_text=true: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 print_module_map option.
 
 // RUN: %clangxx_memprof -O0 %s -o %t
-// RUN: %env_memprof_opts=log_path=stderr:print_module_map=1 %run %t 2>&1 | FileCheck %s
-// RUN: %env_memprof_opts=log_path=stderr:print_module_map=0 %run %t 2>&1 | FileCheck %s --check-prefix=NOMAP
+// RUN: %env_memprof_opts=print_text=true:log_path=stderr:print_module_map=1 %run %t 2>&1 | FileCheck %s
+// RUN: %env_memprof_opts=print_text=true:log_path=stderr:print_module_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
@@ -3,19 +3,19 @@
 //
 // RUN: %clangxx_memprof  %s -o %t
 
-// stderr log_path
-// RUN: %env_memprof_opts=log_path=stderr %run %t 2>&1 | FileCheck %s --check-prefix=CHECK-GOOD --dump-input=always
+// stderr print_text=true:log_path
+// RUN: %env_memprof_opts=print_text=true:log_path=stderr %run %t 2>&1 | FileCheck %s --check-prefix=CHECK-GOOD --dump-input=always
 
-// Good log_path.
+// Good print_text=true:log_path.
 // RUN: rm -f %t.log.*
-// RUN: %env_memprof_opts=log_path=%t.log %run %t
+// RUN: %env_memprof_opts=print_text=true:log_path=%t.log %run %t
 // RUN: FileCheck %s --check-prefix=CHECK-GOOD --dump-input=always < %t.log.*
 
-// Invalid log_path.
-// RUN: %env_memprof_opts=log_path=/dev/null/INVALID not %run %t 2>&1 | FileCheck %s --check-prefix=CHECK-INVALID --dump-input=always
+// Invalid print_text=true:log_path.
+// RUN: %env_memprof_opts=print_text=true:log_path=/dev/null/INVALID not %run %t 2>&1 | FileCheck %s --check-prefix=CHECK-INVALID --dump-input=always
 
-// Too long log_path.
-// RUN: %env_memprof_opts=log_path=`for((i=0;i<10000;i++)); do echo -n $i; done` \
+// Too long print_text=true:log_path.
+// RUN: %env_memprof_opts=print_text=true:log_path=`for((i=0;i<10000;i++)); do echo -n $i; done` \
 // RUN:   not %run %t 2>&1 | FileCheck %s --check-prefix=CHECK-LONG --dump-input=always
 
 // Specifying the log name via the __memprof_profile_filename variable.
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=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
+// RUN: %env_memprof_opts=print_text=true: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=print_text=true: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=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
+// RUN: %env_memprof_opts=print_text=true: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/memprof_merge_mib.cpp b/compiler-rt/test/memprof/TestCases/memprof_merge_mib.cpp
--- a/compiler-rt/test/memprof/TestCases/memprof_merge_mib.cpp
+++ b/compiler-rt/test/memprof/TestCases/memprof_merge_mib.cpp
@@ -1,6 +1,6 @@
 // RUN: %clangxx_memprof  %s -o %t
 
-// RUN: %env_memprof_opts=log_path=stdout %run %t | FileCheck %s
+// RUN: %env_memprof_opts=print_text=true:log_path=stdout %run %t | FileCheck %s
 
 #include <sanitizer/memprof_interface.h>
 #include <stdlib.h>
diff --git a/compiler-rt/test/memprof/TestCases/memprof_profile_dump.cpp b/compiler-rt/test/memprof/TestCases/memprof_profile_dump.cpp
--- a/compiler-rt/test/memprof/TestCases/memprof_profile_dump.cpp
+++ b/compiler-rt/test/memprof/TestCases/memprof_profile_dump.cpp
@@ -1,7 +1,7 @@
 // RUN: %clangxx_memprof  %s -o %t
 
-// RUN: %env_memprof_opts=log_path=stdout %run %t | FileCheck --check-prefix=CHECK-TEXT %s
-// RUN: %env_memprof_opts=log_path=stdout,print_text=false %run %t > %t.memprofraw
+// RUN: %env_memprof_opts=print_text=true:log_path=stdout %run %t | FileCheck --check-prefix=CHECK-TEXT %s
+// RUN: %env_memprof_opts=print_text=true:log_path=stdout,print_text=false %run %t > %t.memprofraw
 // RUN: od -c -N 8 %t.memprofraw | FileCheck --check-prefix=CHECK-RAW %s
 
 #include <sanitizer/memprof_interface.h>
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: %clang_memprof %s -ldl -pthread -o %t
 // RUN: %run %t 0 3
 // RUN: %run %t 2 3
-// 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
+// RUN: %env_memprof_opts=print_text=true:log_path=stderr:verbosity=2 %run %t 10 2 2>&1 | FileCheck %s
+// RUN: %env_memprof_opts=print_text=true:log_path=stderr:verbosity=2:intercept_tls_get_addr=1 %run %t 10 2 2>&1 | FileCheck %s
+// RUN: %env_memprof_opts=print_text=true: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: %clang_memprof -O0 %s -o %t
-// RUN: %env_memprof_opts=log_path=stderr %run %t 2>&1 | FileCheck %s
+// RUN: %env_memprof_opts=print_text=true:log_path=stderr %run %t 2>&1 | FileCheck %s
 
 // RUN: %clang_memprof -DFREE -O0 %s -o %t
-// RUN: %env_memprof_opts=log_path=stderr %run %t 2>&1 | FileCheck %s
+// RUN: %env_memprof_opts=print_text=true: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 && %env_memprof_opts=log_path=stderr %run %t 2>&1 | FileCheck %s
+// RUN: %clangxx_memprof -O0 %s -o %t && %env_memprof_opts=print_text=true: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=log_path=stderr %run %t 2>&1 | FileCheck %s
+// RUN: %env_memprof_opts=print_text=true:log_path=stderr %run %t 2>&1 | FileCheck %s
 
 // RUN: %clangxx_memprof -DFREE -O0 %s -o %t
-// RUN: %env_memprof_opts=log_path=stderr %run %t 2>&1 | FileCheck %s
+// RUN: %env_memprof_opts=print_text=true: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=log_path=stderr %run %t 2>&1 | FileCheck %s
+// RUN: %env_memprof_opts=print_text=true: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=log_path=stderr:print_terse=1 %run %t 2>&1 | FileCheck %s
+// RUN: %env_memprof_opts=print_text=true:log_path=stderr:print_terse=1 %run %t 2>&1 | FileCheck %s
 
 // RUN: %clangxx_memprof -DFREE -O0 %s -o %t
-// RUN: %env_memprof_opts=log_path=stderr:print_terse=1 %run %t 2>&1 | FileCheck %s
+// RUN: %env_memprof_opts=print_text=true: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]]/{{[01]}}/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 && %env_memprof_opts=log_path=stderr %run %t 2>&1 | FileCheck %s
+// RUN: %clangxx_memprof -O0 %s -o %t && %env_memprof_opts=print_text=true:log_path=stderr %run %t 2>&1 | FileCheck %s
 
 // This is actually:
 //  Memory allocation stack id = STACKID
diff --git a/compiler-rt/test/memprof/lit.cfg.py b/compiler-rt/test/memprof/lit.cfg.py
--- a/compiler-rt/test/memprof/lit.cfg.py
+++ b/compiler-rt/test/memprof/lit.cfg.py
@@ -30,7 +30,9 @@
 # Platform-specific default MEMPROF_OPTIONS for lit tests.
 default_memprof_opts = list(config.default_sanitizer_opts)
 
-default_memprof_opts_str = ':'.join(default_memprof_opts)
+# We need a trailing ':' since the substitution from the test is appended to
+# this string.
+default_memprof_opts_str = ':'.join(default_memprof_opts) + ':'
 if default_memprof_opts_str:
   config.environment['MEMPROF_OPTIONS'] = default_memprof_opts_str
 config.substitutions.append(('%env_memprof_opts=',