[compiler-rt][memprof] Disambiguate checks for __tls_get_addr in output

[leonardchan]

Summary

TestCases/stress_dtls.c was failing when we ran memprof tests for the first time. The test checks that __tls_get_addr is not in the output for the last run when it is possible for the interceptor __interceptor___tls_get_addr to be in the output from stack dumps. The test actually intends to check that the various __tls_get_addr reports don't get emitted when intercept_tls_get_addr=0. This updates the test to also check for the following : which should ignore the __interceptor___tls_get_addr interceptor.

[leonardchan]

https://luci-milo.appspot.com/ui/artifact/raw/invocations/u-swarming-2021-10-04-23-04-00-7ae3a948d9c5c831/tests/MemProfiler-x86_64-linux%20::%20TestCases%2Fstress_dtls.c/results/7705c5d3-01778/artifacts/artifact-content-in-request contains the full log for the failure. One thing worth noting is that I couldn't reproduce this locally, so I'm not entirely sure if this patch is the right way to approach this and it's just sweeping something under the rug.

[MaskRay]

May be more robust to use ==__tls_get_addr: to ensure the printed line is not __interceptor___tls_get_addr

[tejohnson]

lgtm, but I like @MaskRay 's suggested change. I ran it locally and don't see any stack traces that involve __libc_memalign, so perhaps that is only used in some environments. I looked at some documentation and it appears to be dependent on the version of libc used. So that could explain why it is only showing up in some cases.

compiler-rt/test/memprof/TestCases/stress_dtls.c

 // REQUIRES: memprof-64-bits
 // Stress test dynamic TLS + dlopen + threads.
 //
 // RUN: %clang_memprof -x c -DSO_NAME=f0 %s -shared -o %t-f0.so -fPIC
 // RUN: %clang_memprof -x c -DSO_NAME=f1 %s -shared -o %t-f1.so -fPIC
 // RUN: %clang_memprof -x c -DSO_NAME=f2 %s -shared -o %t-f2.so -fPIC
 // 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
-// CHECK: __tls_get_addr
+// CHECK: ==__tls_get_addr:
 // CHECK: Creating thread 0
-// CHECK: __tls_get_addr
+// CHECK: ==__tls_get_addr:
 // CHECK: Creating thread 1
-// CHECK: __tls_get_addr
+// CHECK: ==__tls_get_addr:
 // CHECK: Creating thread 2
-// CHECK: __tls_get_addr
+// CHECK: ==__tls_get_addr:
 // CHECK: Creating thread 3
-// CHECK: __tls_get_addr
+// CHECK: ==__tls_get_addr:
 // Make sure that TLS slots don't leak
 // CHECK-NOT: num_live_dtls 5
 //
-// CHECK0-NOT: __tls_get_addr
+// CHECK0-NOT: ==__tls_get_addr:
 /*
 cc=your-compiler
 
 $cc stress_dtls.c -pthread -ldl
 for((i=0;i<100;i++)); do
   $cc -fPIC -shared -DSO_NAME=f$i -o a.out-f$i.so stress_dtls.c;
 done
 ./a.out 2 4  # <<<<<< 2 threads, 4 libs