[vm, fuchsia] Consume specialized symbols for the Dart VM's profiler.

Bug: FL-238
Change-Id: Ie5e2786aeb47063ea1c534b2169b2547d6693a96
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/100200
Reviewed-by: Zach Anderson <zra@google.com>
Commit-Queue: Ryan Macnak <rmacnak@google.com>

runtime/bin/BUILD.gn

@@ -36,9 +36,6 @@ template("build_libdart_builtin") {
                  "..:dart_arch_config",
                  "..:dart_config",
                ] + extra_configs
-    if (is_fuchsia) {
-      configs -= [ "//build/config:symbol_visibility_hidden" ]
-    }
     public_configs = [ ":libdart_builtin_config" ]
     deps = []
     if (is_fuchsia) {
@@ -90,9 +87,6 @@ static_library("crashpad") {
     "..:dart_product_config",
     "..:dart_os_fuchsia_config",
   ]
-  if (is_fuchsia) {
-    configs -= [ "//build/config:symbol_visibility_hidden" ]
-  }
   include_dirs = [ ".." ]
   sources = [
     "crashpad.cc",
@@ -127,9 +121,6 @@ template("build_gen_snapshot") {
                  "..:dart_config",
                  "..:dart_precompiler_config",
                ] + extra_configs
-    if (is_fuchsia) {
-      configs -= [ "//build/config:symbol_visibility_hidden" ]
-    }
     deps = [ ":generate_abi_version_cc_file" ] + extra_deps
 
     defines = [ "EXCLUDE_CFE_AND_KERNEL_PLATFORM" ]
@@ -263,7 +254,6 @@ template("build_gen_snapshot_dart_io") {
       public_deps = [
         "//zircon/public/lib/fdio",
       ]
-      configs -= [ "//build/config:symbol_visibility_hidden" ]
     }
 
     deps += [ "//third_party/zlib" ]
@@ -345,9 +335,6 @@ template("dart_io") {
                  "..:dart_os_config",
                ] + extra_configs
     public_configs = [ "..:dart_public_config" ]
-    if (is_fuchsia) {
-      configs -= [ "//build/config:symbol_visibility_hidden" ]
-    }
     custom_sources_filter = [
       "*_test.cc",
       "*_test.h",
@@ -698,9 +685,6 @@ template("dart_executable") {
                  "..:dart_os_config",
                  "..:dart_maybe_product_config",
                ] + extra_configs
-    if (is_fuchsia) {
-      configs -= [ "//build/config:symbol_visibility_hidden" ]
-    }
     if (target_os != current_os && target_os == "fuchsia") {
       # We already have these in the standalone build, but Fuchsia doesn't
       # have them. They are needed for running Fuchsia binaries built for the
@@ -906,9 +890,6 @@ executable("run_vm_tests") {
   if (dart_target_arch != "ia32") {
     configs += [ "..:dart_precompiler_config" ]
   }
-  if (is_fuchsia) {
-    configs -= [ "//build/config:symbol_visibility_hidden" ]
-  }
 
   deps = [
     ":crashpad",

runtime/configs.gni

@@ -156,9 +156,6 @@ template("library_for_all_configs") {
                                "extra_deps",
                                "configurable_deps",
                              ])
-      if (is_fuchsia) {
-        configs -= [ "//build/config:symbol_visibility_hidden" ]
-      }
       configs += conf.configs + extra_configs
       configured_deps = []
       foreach(dep, configurable_deps) {

runtime/include/dart_api.h

@@ -975,6 +975,16 @@ DART_EXPORT void Dart_ThreadDisableProfiling();
  */
 DART_EXPORT void Dart_ThreadEnableProfiling();
 
+/**
+ * Register symbol information for the Dart VM's profiler and crash dumps.
+ *
+ * This consumes the output of //topaz/runtime/dart/profiler_symbols, which
+ * should be treated as opaque.
+ */
+DART_EXPORT void Dart_AddSymbols(const char* dso_name,
+                                 void* buffer,
+                                 intptr_t buffer_size);
+
 /**
  * Exits an isolate. After this call, Dart_CurrentIsolate will
  * return NULL.

runtime/third_party/double-conversion/src/BUILD.gn

@@ -8,9 +8,6 @@ source_set("libdouble_conversion") {
     "../../..:dart_config",
     "../../..:dart_os_config",
   ]
-  if (is_fuchsia) {
-    configs -= [ "//build/config:symbol_visibility_hidden" ]
-  }
   sources = [
     "bignum-dtoa.cc",
     "bignum-dtoa.h",

runtime/vm/dart_api_impl.cc

@@ -33,6 +33,7 @@
 #include "vm/message.h"
 #include "vm/message_handler.h"
 #include "vm/native_entry.h"
+#include "vm/native_symbol.h"
 #include "vm/object.h"
 #include "vm/object_store.h"
 #include "vm/os.h"
@@ -1280,6 +1281,12 @@ DART_EXPORT void Dart_ThreadEnableProfiling() {
   os_thread->EnableThreadInterrupts();
 }
 
+DART_EXPORT void Dart_AddSymbols(const char* dso_name,
+                                 void* buffer,
+                                 intptr_t buffer_size) {
+  NativeSymbolResolver::AddSymbols(dso_name, buffer, buffer_size);
+}
+
 DART_EXPORT bool Dart_WriteProfileToTimeline(Dart_Port main_port,
                                              char** error) {
 #if defined(PRODUCT)

runtime/vm/native_symbol.h

@@ -19,6 +19,7 @@ class NativeSymbolResolver : public AllStatic {
   static char* LookupSymbolName(uintptr_t pc, uintptr_t* start);
   static bool LookupSharedObject(uword pc, uword* dso_base, char** dso_name);
   static void FreeSymbolName(char* name);
+  static void AddSymbols(const char* dso_name, void* buffer, size_t size);
 };
 
 }  // namespace dart

runtime/vm/native_symbol_android.cc

@@ -6,6 +6,7 @@
 #if defined(HOST_OS_ANDROID)
 
 #include "vm/native_symbol.h"
+#include "vm/os.h"
 
 #include <cxxabi.h>  // NOLINT
 #include <dlfcn.h>   // NOLINT
@@ -55,6 +56,12 @@ bool NativeSymbolResolver::LookupSharedObject(uword pc,
   return true;
 }
 
+void NativeSymbolResolver::AddSymbols(const char* dso_name,
+                                      void* buffer,
+                                      size_t size) {
+  OS::PrintErr("warning: Dart_AddSymbols has no effect on Android\n");
+}
+
 }  // namespace dart
 
 #endif  // defined(HOST_OS_ANDROID)

runtime/vm/native_symbol_fuchsia.cc

@@ -8,14 +8,97 @@
 #include "platform/memory_sanitizer.h"
 #include "vm/native_symbol.h"
 
-#include <cxxabi.h>  // NOLINT
 #include <dlfcn.h>   // NOLINT
 
 namespace dart {
 
+// On Fuchsia, in lieu of the ELF dynamic symbol table consumed through dladdr,
+// we consumes symbols produced by //topaz/runtime/dart/profiler_symbols and
+// provided to the VM by the embedder through Dart_AddSymbols. They have the
+// format
+//
+// struct {
+//    uint32_t num_entries;
+//    struct {
+//      uint32_t offset;
+//      uint32_t size;
+//      uint32_t string_table_offset;
+//    } entries[num_entries];
+//    const char* string_table;
+// }
+//
+// Entries are sorted by offset. String table entries are NUL-terminated.
+class NativeSymbols {
+ public:
+  NativeSymbols(const char* dso_name, void* buffer, size_t size)
+      : next_(NULL), dso_name_(dso_name) {
+    num_entries_ = *reinterpret_cast<uint32_t*>(buffer);
+    entries_ =
+        reinterpret_cast<Entry*>(reinterpret_cast<uint32_t*>(buffer) + 1);
+    name_table_ = reinterpret_cast<const char*>(entries_ + num_entries_);
+  }
+
+  NativeSymbols* next() const { return next_; }
+  void set_next(NativeSymbols* symbols) { next_ = symbols; }
+
+  bool Lookup(const char* dso_name,
+              uword dso_offset,
+              uword* start_offset,
+              const char** name) {
+    if (strcmp(dso_name, dso_name_) != 0) {
+      return false;
+    }
+
+    intptr_t lo = 0;
+    intptr_t hi = num_entries_ - 1;
+    while (lo <= hi) {
+      intptr_t mid = (hi - lo + 1) / 2 + lo;
+      ASSERT(mid >= lo);
+      ASSERT(mid <= hi);
+      const Entry& entry = entries_[mid];
+      if (dso_offset < entry.offset) {
+        hi = mid - 1;
+      } else if (dso_offset >= (entry.offset + entry.size)) {
+        lo = mid + 1;
+      } else {
+        *start_offset = entry.offset;
+        *name = &name_table_[entry.name_offset];
+        return true;
+      }
+    }
+
+    return false;
+  }
+
+ private:
+  struct Entry {
+    uint32_t offset;
+    uint32_t size;
+    uint32_t name_offset;
+  };
+
+  NativeSymbols* next_;
+  const char* const dso_name_;
+  uint32_t num_entries_;
+  Entry* entries_;
+  const char* name_table_;
+
+  DISALLOW_COPY_AND_ASSIGN(NativeSymbols);
+};
+
+static NativeSymbols* symbols_ = NULL;
+
 void NativeSymbolResolver::Init() {}
 
-void NativeSymbolResolver::Cleanup() {}
+void NativeSymbolResolver::Cleanup() {
+  NativeSymbols* symbols = symbols_;
+  symbols_ = NULL;
+  while (symbols != NULL) {
+    NativeSymbols* next = symbols->next();
+    delete symbols;
+    symbols = next;
+  }
+}
 
 char* NativeSymbolResolver::LookupSymbolName(uintptr_t pc, uintptr_t* start) {
   Dl_info info;
@@ -23,20 +106,25 @@ char* NativeSymbolResolver::LookupSymbolName(uintptr_t pc, uintptr_t* start) {
   if (r == 0) {
     return NULL;
   }
-  if (info.dli_sname == NULL) {
-    return NULL;
+
+  const char* dso_name = info.dli_fname;
+  uword dso_base = reinterpret_cast<uword>(info.dli_fbase);
+  uword dso_offset = pc - dso_base;
+
+  for (NativeSymbols* symbols = symbols_; symbols != NULL;
+       symbols = symbols->next()) {
+    uword symbol_start_offset;
+    const char* symbol_name;
+    if (symbols->Lookup(dso_name, dso_offset, &symbol_start_offset,
+                        &symbol_name)) {
+      if (start != NULL) {
+        *start = symbol_start_offset + dso_base;
+      }
+      return strdup(symbol_name);
+    }
   }
-  if (start != NULL) {
-    *start = reinterpret_cast<uintptr_t>(info.dli_saddr);
-  }
-  int status = 0;
-  size_t len = 0;
-  char* demangled = abi::__cxa_demangle(info.dli_sname, NULL, &len, &status);
-  MSAN_UNPOISON(demangled, len);
-  if (status == 0) {
-    return demangled;
-  }
-  return strdup(info.dli_sname);
+
+  return NULL;
 }
 
 void NativeSymbolResolver::FreeSymbolName(char* name) {
@@ -56,6 +144,13 @@ bool NativeSymbolResolver::LookupSharedObject(uword pc,
   return true;
 }
 
+void NativeSymbolResolver::AddSymbols(const char* dso_name,
+                                      void* buffer, size_t size) {
+  NativeSymbols* symbols = new NativeSymbols(dso_name, buffer, size);
+  symbols->set_next(symbols_);
+  symbols_ = symbols;
+}
+
 }  // namespace dart
 
 #endif  // defined(HOST_OS_FUCHSIA)

runtime/vm/native_symbol_linux.cc

@@ -7,6 +7,7 @@
 
 #include "platform/memory_sanitizer.h"
 #include "vm/native_symbol.h"
+#include "vm/os.h"
 
 #include <cxxabi.h>  // NOLINT
 #include <dlfcn.h>   // NOLINT
@@ -56,6 +57,12 @@ bool NativeSymbolResolver::LookupSharedObject(uword pc,
   return true;
 }
 
+void NativeSymbolResolver::AddSymbols(const char* dso_name,
+                                      void* buffer,
+                                      size_t size) {
+  OS::PrintErr("warning: Dart_AddSymbols has no effect on Linux\n");
+}
+
 }  // namespace dart
 
 #endif  // defined(HOST_OS_LINUX)

runtime/vm/native_symbol_macos.cc

@@ -6,6 +6,7 @@
 #if defined(HOST_OS_MACOS)
 
 #include "vm/native_symbol.h"
+#include "vm/os.h"
 
 #include <cxxabi.h>  // NOLINT
 #include <dlfcn.h>   // NOLINT
@@ -53,6 +54,12 @@ bool NativeSymbolResolver::LookupSharedObject(uword pc,
   return true;
 }
 
+void NativeSymbolResolver::AddSymbols(const char* dso_name,
+                                      void* buffer,
+                                      size_t size) {
+  OS::PrintErr("warning: Dart_AddSymbols has no effect on MacOS\n");
+}
+
 }  // namespace dart
 
 #endif  // defined(HOST_OS_MACOS)

runtime/vm/native_symbol_win.cc

@@ -7,6 +7,7 @@
 
 #include "vm/lockers.h"
 #include "vm/native_symbol.h"
+#include "vm/os.h"
 #include "vm/os_thread.h"
 
 #include <dbghelp.h>  // NOLINT
@@ -83,6 +84,12 @@ bool NativeSymbolResolver::LookupSharedObject(uword pc,
   return false;
 }
 
+void NativeSymbolResolver::AddSymbols(const char* dso_name,
+                                      void* buffer,
+                                      size_t size) {
+  OS::PrintErr("warning: Dart_AddSymbols has no effect on Windows\n");
+}
+
 }  // namespace dart
 
 #endif  // defined(HOST_OS_WINDOWS)