diff --git a/llvm/unittests/tools/llvm-exegesis/X86/SubprocessMemoryTest.cpp b/llvm/unittests/tools/llvm-exegesis/X86/SubprocessMemoryTest.cpp
--- a/llvm/unittests/tools/llvm-exegesis/X86/SubprocessMemoryTest.cpp
+++ b/llvm/unittests/tools/llvm-exegesis/X86/SubprocessMemoryTest.cpp
@@ -10,12 +10,14 @@
 
 #include "X86/TestBase.h"
 #include "gtest/gtest.h"
+#include <string>
 #include <unordered_map>
 
 #ifdef __linux__
 #include <endian.h>
 #include <fcntl.h>
 #include <sys/mman.h>
+#include <unistd.h>
 #endif // __linux__
 
 namespace llvm {
@@ -25,11 +27,21 @@
 
 class SubprocessMemoryTest : public X86TestBase {
 protected:
+  // In this function and below, TestNumber is a one-based index of the test
+  // rather than a zero-based index of the test so that the zero-case doesn't
+  // cancel out the differentiation provided by the process PID.
   void
   testCommon(std::unordered_map<std::string, MemoryValue> MemoryDefinitions,
-             const int MainProcessPID) {
-    EXPECT_FALSE(SM.initializeSubprocessMemory(MainProcessPID));
-    EXPECT_FALSE(SM.addMemoryDefinition(MemoryDefinitions, MainProcessPID));
+             const unsigned TestNumber) {
+    EXPECT_FALSE(SM.initializeSubprocessMemory(getpid() * TestNumber));
+    EXPECT_FALSE(
+        SM.addMemoryDefinition(MemoryDefinitions, getpid() * TestNumber));
+  }
+
+  std::string getSharedMemoryName(const unsigned TestNumber,
+                                  const unsigned DefinitionNumber) {
+    return "/" + std::to_string(getpid() * TestNumber) + "memdef" +
+           std::to_string(DefinitionNumber);
   }
 
   void checkSharedMemoryDefinition(const std::string &DefinitionName,
@@ -58,8 +70,9 @@
 #else
 TEST_F(SubprocessMemoryTest, OneDefinition) {
 #endif
-  testCommon({{"test1", {APInt(8, 0xff), 4096, 0}}}, 0);
-  checkSharedMemoryDefinition("/0memdef0", 4096, {0xff});
+  testCommon({{"test1", {APInt(8, 0xff), 4096, 0}}}, 1);
+  std::cout << getSharedMemoryName(1, 0) << "\n";
+  checkSharedMemoryDefinition(getSharedMemoryName(1, 0), 4096, {0xff});
 }
 
 #if defined(__powerpc__) || defined(__s390x__)
@@ -70,10 +83,10 @@
   testCommon({{"test1", {APInt(8, 0xaa), 4096, 0}},
               {"test2", {APInt(8, 0xbb), 4096, 1}},
               {"test3", {APInt(8, 0xcc), 4096, 2}}},
-             1);
-  checkSharedMemoryDefinition("/1memdef0", 4096, {0xaa});
-  checkSharedMemoryDefinition("/1memdef1", 4096, {0xbb});
-  checkSharedMemoryDefinition("/1memdef2", 4096, {0xcc});
+             2);
+  checkSharedMemoryDefinition(getSharedMemoryName(2, 0), 4096, {0xaa});
+  checkSharedMemoryDefinition(getSharedMemoryName(2, 1), 4096, {0xbb});
+  checkSharedMemoryDefinition(getSharedMemoryName(2, 2), 4096, {0xcc});
 }
 
 #if defined(__powerpc__) || defined(__s390x__)
@@ -84,13 +97,13 @@
   testCommon({{"test1", {APInt(8, 0xaa), 4096, 0}},
               {"test2", {APInt(16, 0xbbbb), 4096, 1}},
               {"test3", {APInt(24, 0xcccccc), 4096, 2}}},
-             2);
+             3);
   std::vector<uint8_t> Test1Expected(512, 0xaa);
   std::vector<uint8_t> Test2Expected(512, 0xbb);
   std::vector<uint8_t> Test3Expected(512, 0xcc);
-  checkSharedMemoryDefinition("/2memdef0", 4096, Test1Expected);
-  checkSharedMemoryDefinition("/2memdef1", 4096, Test2Expected);
-  checkSharedMemoryDefinition("/2memdef2", 4096, Test3Expected);
+  checkSharedMemoryDefinition(getSharedMemoryName(3, 0), 4096, Test1Expected);
+  checkSharedMemoryDefinition(getSharedMemoryName(3, 1), 4096, Test2Expected);
+  checkSharedMemoryDefinition(getSharedMemoryName(3, 2), 4096, Test3Expected);
 }
 
 // The following test is only supported on little endian systems.
@@ -99,7 +112,7 @@
 #else
 TEST_F(SubprocessMemoryTest, DefinitionEndTruncation) {
 #endif
-  testCommon({{"test1", {APInt(48, 0xaabbccddeeff), 4096, 0}}}, 3);
+  testCommon({{"test1", {APInt(48, 0xaabbccddeeff), 4096, 0}}}, 4);
   std::vector<uint8_t> Test1Expected(512, 0);
   // order is reversed since we're assuming a little endian system.
   for (size_t I = 0; I < Test1Expected.size(); ++I) {
@@ -123,7 +136,7 @@
       Test1Expected[I] = 0xaa;
     }
   }
-  checkSharedMemoryDefinition("/3memdef0", 4096, Test1Expected);
+  checkSharedMemoryDefinition(getSharedMemoryName(4, 0), 4096, Test1Expected);
 }
 
 #endif // defined(__linux__) && !defined(__ANDROID__)