Revert "[LSan] Detect dynamic loader by its base address."

This reverts commit r315024.

Breaks sysconf_interceptor_bypass_test.cc

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@315031 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 18 insertions, 29 deletions

diff --git a/lib/lsan/lsan_common.cc b/lib/lsan/lsan_common.cc
index 651bbe1f3..622aae734 100644
--- a/lib/lsan/lsan_common.cc
+++ b/lib/lsan/lsan_common.cc
@@ -411,9 +411,8 @@ static void MarkInvalidPCCb(uptr chunk, void *arg) {
   }
 }
 
-// On Linux, treats all chunks allocated from ld-linux.so as reachable, which
-// covers dynamically allocated TLS blocks, internal dynamic loader's loaded
-// modules accounting etc.
+// On Linux, handles dynamically allocated TLS blocks by treating all chunks
+// allocated from ld-linux.so as reachable.
 // Dynamic TLS blocks contain the TLS variables of dynamically loaded modules.
 // They are allocated with a __libc_memalign() call in allocate_and_init()
 // (elf/dl-tls.c). Glibc won't tell us the address ranges occupied by those
diff --git a/lib/lsan/lsan_common_linux.cc b/lib/lsan/lsan_common_linux.cc
index 5acff0b2d..5042c7b3a 100644
--- a/lib/lsan/lsan_common_linux.cc
+++ b/lib/lsan/lsan_common_linux.cc
@@ -23,10 +23,6 @@
 #include "sanitizer_common/sanitizer_linux.h"
 #include "sanitizer_common/sanitizer_stackdepot.h"
 
-#if SANITIZER_USE_GETAUXVAL
-#include <sys/auxv.h>
-#endif  // SANITIZER_USE_GETAUXVAL
-
 namespace __lsan {
 
 static const char kLinkerName[] = "ld";
@@ -34,12 +30,8 @@ static const char kLinkerName[] = "ld";
 static char linker_placeholder[sizeof(LoadedModule)] ALIGNED(64);
 static LoadedModule *linker = nullptr;
 
-static bool IsLinker(const LoadedModule& module) {
-#if SANITIZER_USE_GETAUXVAL
-  return module.base_address() == getauxval(AT_BASE);
-#else
-  return LibraryNameIs(module.full_name(), kLinkerName);
-#endif  // SANITIZER_USE_GETAUXVAL
+static bool IsLinker(const char* full_name) {
+  return LibraryNameIs(full_name, kLinkerName);
 }
 
 __attribute__((tls_model("initial-exec")))
@@ -57,25 +49,22 @@ void InitializePlatformSpecificModules() {
   ListOfModules modules;
   modules.init();
   for (LoadedModule &module : modules) {
-    if (!IsLinker(module))
-      continue;
+    if (!IsLinker(module.full_name())) continue;
     if (linker == nullptr) {
       linker = reinterpret_cast<LoadedModule *>(linker_placeholder);
       *linker = module;
       module = LoadedModule();
     } else {
       VReport(1, "LeakSanitizer: Multiple modules match \"%s\". "
-              "TLS and other allocations originating from linker might be "
-              "falsely reported as leaks.\n", kLinkerName);
+              "TLS will not be handled correctly.\n", kLinkerName);
       linker->clear();
       linker = nullptr;
       return;
     }
   }
   if (linker == nullptr) {
-    VReport(1, "LeakSanitizer: Dynamic linker not found. TLS and other "
-               "allocations originating from linker might be falsely reported "
-                "as leaks.\n");
+    VReport(1, "LeakSanitizer: Dynamic linker not found. "
+               "TLS will not be handled correctly.\n");
   }
 }
 
diff --git a/lib/sanitizer_common/sanitizer_linux.cc b/lib/sanitizer_common/sanitizer_linux.cc
index f239b4fba..48c53d46d 100644
--- a/lib/sanitizer_common/sanitizer_linux.cc
+++ b/lib/sanitizer_common/sanitizer_linux.cc
@@ -93,6 +93,16 @@ extern char **environ;  // provided by crt1
 #include <sys/signal.h>
 #endif
 
+#ifndef __GLIBC_PREREQ
+#define __GLIBC_PREREQ(x, y) 0
+#endif
+
+#if SANITIZER_LINUX && __GLIBC_PREREQ(2, 16)
+# define SANITIZER_USE_GETAUXVAL 1
+#else
+# define SANITIZER_USE_GETAUXVAL 0
+#endif
+
 #if SANITIZER_USE_GETAUXVAL
 #include <sys/auxv.h>
 #endif
diff --git a/lib/sanitizer_common/sanitizer_platform.h b/lib/sanitizer_common/sanitizer_platform.h
index 763d6e01b..81d9164c3 100644
--- a/lib/sanitizer_common/sanitizer_platform.h
+++ b/lib/sanitizer_common/sanitizer_platform.h
@@ -282,14 +282,5 @@
 # define SANITIZER_SUPPRESS_LEAK_ON_PTHREAD_EXIT 0
 #endif
 
-#ifndef __GLIBC_PREREQ
-#define __GLIBC_PREREQ(x, y) 0
-#endif
-
-#if SANITIZER_LINUX && __GLIBC_PREREQ(2, 16)
-# define SANITIZER_USE_GETAUXVAL 1
-#else
-# define SANITIZER_USE_GETAUXVAL 0
-#endif
 
 #endif // SANITIZER_PLATFORM_H