[Darwin] Remove workaround for symbolication in iOS simulator runtimes

A while ago we added some code to the sanitizer runtimes for iOS
simulators to allow `atos` (external process) to inspect the sanitized
process during report generation to enable symbolication.  This was done
by setting the `__check_mach_ports_lookup` env var early during process
startup which came with a couple of complications.

This workaround is not required anymore and removing it fixes TSan in
the iOS simulator after the new TSan runtime landed.
(https://reviews.llvm.org/D112603)

Relevant/reverted revisions:
https://reviews.llvm.org/D78178
https://reviews.llvm.org/D78179
https://reviews.llvm.org/D78525

rdar://86472733

Differential Revision: https://reviews.llvm.org/D115767

compiler-rt/lib/sanitizer_common/sanitizer_symbolizer.cpp

@@ -138,10 +138,4 @@ Symbolizer::SymbolizerScope::~SymbolizerScope() {
     sym_->end_hook_();
 }
 
-void Symbolizer::LateInitializeTools() {
-  for (auto &tool : tools_) {
-    tool.LateInitialize();
-  }
-}
-
 }  // namespace __sanitizer

compiler-rt/lib/sanitizer_common/sanitizer_symbolizer.h

@@ -213,9 +213,6 @@ class Symbolizer final {
    private:
     const Symbolizer *sym_;
   };
-
-  // Calls `LateInitialize()` on all items in `tools_`.
-  void LateInitializeTools();
 };
 
 #ifdef SANITIZER_WINDOWS

compiler-rt/lib/sanitizer_common/sanitizer_symbolizer_internal.h

@@ -70,11 +70,6 @@ class SymbolizerTool {
     return nullptr;
   }
 
-  // Called during the LateInitialize phase of Sanitizer initialization.
-  // Usually this is a safe place to call code that might need to use user
-  // memory allocators.
-  virtual void LateInitialize() {}
-
  protected:
   ~SymbolizerTool() {}
 };

compiler-rt/lib/sanitizer_common/sanitizer_symbolizer_mac.cpp

@@ -20,7 +20,6 @@
 
 #include <dlfcn.h>
 #include <errno.h>
-#include <mach/mach.h>
 #include <stdlib.h>
 #include <sys/wait.h>
 #include <unistd.h>
@@ -58,13 +57,6 @@ bool DlAddrSymbolizer::SymbolizeData(uptr addr, DataInfo *datainfo) {
   return true;
 }
 
-#define K_ATOS_ENV_VAR "__check_mach_ports_lookup"
-
-// This cannot live in `AtosSymbolizerProcess` because instances of that object
-// are allocated by the internal allocator which under ASan is poisoned with
-// kAsanInternalHeapMagic.
-static char kAtosMachPortEnvEntry[] = K_ATOS_ENV_VAR "=000000000000000";
-
 class AtosSymbolizerProcess final : public SymbolizerProcess {
  public:
   explicit AtosSymbolizerProcess(const char *path)
@@ -72,51 +64,13 @@ class AtosSymbolizerProcess final : public SymbolizerProcess {
     pid_str_[0] = '\0';
   }
 
-  void LateInitialize() {
-    if (SANITIZER_IOSSIM) {
-      // `putenv()` may call malloc/realloc so it is only safe to do this
-      // during LateInitialize() or later (i.e. we can't do this in the
-      // constructor).  We also can't do this in `StartSymbolizerSubprocess()`
-      // because in TSan we switch allocators when we're symbolizing.
-      // We use `putenv()` rather than `setenv()` so that we can later directly
-      // write into the storage without LibC getting involved to change what the
-      // variable is set to
-      int result = putenv(kAtosMachPortEnvEntry);
-      CHECK_EQ(result, 0);
-    }
-  }
-
  private:
   bool StartSymbolizerSubprocess() override {
-    // Configure sandbox before starting atos process.
-
     // Put the string command line argument in the object so that it outlives
     // the call to GetArgV.
     internal_snprintf(pid_str_, sizeof(pid_str_), "%d", internal_getpid());
 
-    if (SANITIZER_IOSSIM) {
-      // `atos` in the simulator is restricted in its ability to retrieve the
-      // task port for the target process (us) so we need to do extra work
-      // to pass our task port to it.
-      mach_port_t ports[]{mach_task_self()};
-      kern_return_t ret =
-          mach_ports_register(mach_task_self(), ports, /*count=*/1);
-      CHECK_EQ(ret, KERN_SUCCESS);
-
-      // Set environment variable that signals to `atos` that it should look
-      // for our task port. We can't call `setenv()` here because it might call
-      // malloc/realloc. To avoid that we instead update the
-      // `mach_port_env_var_entry_` variable with our current PID.
-      uptr count = internal_snprintf(kAtosMachPortEnvEntry,
-                                     sizeof(kAtosMachPortEnvEntry),
-                                     K_ATOS_ENV_VAR "=%s", pid_str_);
-      CHECK_GE(count, sizeof(K_ATOS_ENV_VAR) + internal_strlen(pid_str_));
-      // Document our assumption but without calling `getenv()` in normal
-      // builds.
-      DCHECK(getenv(K_ATOS_ENV_VAR));
-      DCHECK_EQ(internal_strcmp(getenv(K_ATOS_ENV_VAR), pid_str_), 0);
-    }
-
+    // Configure sandbox before starting atos process.
     return SymbolizerProcess::StartSymbolizerSubprocess();
   }
 
@@ -140,10 +94,6 @@ class AtosSymbolizerProcess final : public SymbolizerProcess {
   }
 
   char pid_str_[16];
-  // Space for `\0` in `K_ATOS_ENV_VAR` is reused for `=`.
-  static_assert(sizeof(kAtosMachPortEnvEntry) ==
-                    (sizeof(K_ATOS_ENV_VAR) + sizeof(pid_str_)),
-                "sizes should match");
 };
 
 #undef K_ATOS_ENV_VAR
@@ -249,8 +199,6 @@ bool AtosSymbolizer::SymbolizeData(uptr addr, DataInfo *info) {
   return true;
 }
 
-void AtosSymbolizer::LateInitialize() { process_->LateInitialize(); }
-
 }  // namespace __sanitizer
 
 #endif  // SANITIZER_MAC

compiler-rt/lib/sanitizer_common/sanitizer_symbolizer_mac.h

@@ -35,7 +35,6 @@ class AtosSymbolizer final : public SymbolizerTool {
 
   bool SymbolizePC(uptr addr, SymbolizedStack *stack) override;
   bool SymbolizeData(uptr addr, DataInfo *info) override;
-  void LateInitialize() override;
 
  private:
   AtosSymbolizerProcess *process_;

compiler-rt/lib/sanitizer_common/sanitizer_symbolizer_markup.cpp

@@ -100,9 +100,7 @@ Symbolizer *Symbolizer::PlatformInit() {
   return new (symbolizer_allocator_) Symbolizer({});
 }
 
-void Symbolizer::LateInitialize() {
-  Symbolizer::GetOrInit()->LateInitializeTools();
-}
+void Symbolizer::LateInitialize() { Symbolizer::GetOrInit(); }
 
 void StartReportDeadlySignal() {}
 void ReportDeadlySignal(const SignalContext &sig, u32 tid,

compiler-rt/lib/sanitizer_common/sanitizer_symbolizer_posix_libcdep.cpp

@@ -492,7 +492,7 @@ Symbolizer *Symbolizer::PlatformInit() {
 }
 
 void Symbolizer::LateInitialize() {
-  Symbolizer::GetOrInit()->LateInitializeTools();
+  Symbolizer::GetOrInit();
   InitializeSwiftDemangler();
 }
 

compiler-rt/lib/sanitizer_common/sanitizer_symbolizer_win.cpp

@@ -318,7 +318,7 @@ Symbolizer *Symbolizer::PlatformInit() {
 }
 
 void Symbolizer::LateInitialize() {
-  Symbolizer::GetOrInit()->LateInitializeTools();
+  Symbolizer::GetOrInit();
 }
 
 }  // namespace __sanitizer