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// Copyright (c) 2016, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
#include "vm/globals.h"
#if defined(HOST_OS_FUCHSIA)
#include "platform/memory_sanitizer.h"
#include "vm/native_symbol.h"
#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_;
intptr_t num_entries_;
Entry* entries_;
const char* name_table_;
DISALLOW_COPY_AND_ASSIGN(NativeSymbols);
};
static NativeSymbols* symbols_ = NULL;
void NativeSymbolResolver::Init() {}
void NativeSymbolResolver::Cleanup() {
NativeSymbols* symbols = symbols_;
symbols_ = NULL;
while (symbols != NULL) {
NativeSymbols* next = symbols->next();
delete symbols;
symbols = next;
}
}
char* NativeSymbolResolver::LookupSymbolName(uword pc, uword* start) {
Dl_info info;
int r = dladdr(reinterpret_cast<void*>(pc), &info);
if (r == 0) {
return NULL;
}
auto const dso_name = info.dli_fname;
const auto dso_base = reinterpret_cast<uword>(info.dli_fbase);
const auto 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);
}
}
return NULL;
}
void NativeSymbolResolver::FreeSymbolName(char* name) {
free(name);
}
bool NativeSymbolResolver::LookupSharedObject(uword pc,
uword* dso_base,
char** dso_name) {
Dl_info info;
int r = dladdr(reinterpret_cast<void*>(pc), &info);
if (r == 0) {
return false;
}
if (dso_base != nullptr) {
*dso_base = reinterpret_cast<uword>(info.dli_fbase);
}
if (dso_name != nullptr) {
*dso_name = strdup(info.dli_fname);
}
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)