[vm] Support 16k page size on Android.

- Increase the size of the FFI trampoline template. - Increase alignment of ELF binaries generated by the VM. - Pass flags for binaries generated by the NDK's linker increase alignment. - Runtime allocation already either rounds up to the runtime-queried page size or assumes it is no more than 512k. TEST=ci, readelf Bug: go/16k-app-guide Change-Id: I4fdb2a47534a6a24875e205c3a357b5415ca18b8 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/321302 Commit-Queue: Ryan Macnak <[email protected]> Reviewed-by: Liam Appelbe <[email protected]> Reviewed-by: Slava Egorov <[email protected]>
dart-lang · Aug 17, 2023 · 6dcbc9f · 6dcbc9f
1 parent edaea9b
commit 6dcbc9f
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Showing 5 changed files with 10 additions and 1 deletion.
diff --git a/build/config/compiler/BUILD.gn b/build/config/compiler/BUILD.gn
@@ -388,6 +388,10 @@ config("compiler") {
       "-Wl,--exclude-libs=libc++_static.a",
 
       "-fuse-ld=lld",
+
+      # Currently defaults to 4k, but Android will be moving to 16k page size,
+      # and for future-proofing, 64k boundaries will be required.
+      "-Wl,-z,max-page-size=65536",
     ]
 
     if (is_clang) {

diff --git a/pkg/test_runner/lib/src/compiler_configuration.dart b/pkg/test_runner/lib/src/compiler_configuration.dart
@@ -1025,6 +1025,7 @@ class PrecompilerCompilerConfiguration extends CompilerConfiguration
           "$host-x86_64/bin/$abiTriple-gcc";
       shared = '-shared';
       ldFlags.add('-Wl,--no-undefined');
+      ldFlags.add('-Wl,-z,max-page-size=65536');
     } else if (Platform.isLinux) {
       if (_isSimArm || (_isArm && _configuration.useQemu)) {
         cc = 'arm-linux-gnueabihf-gcc';

diff --git a/runtime/vm/elf.h b/runtime/vm/elf.h
@@ -25,6 +25,8 @@ namespace dart {
 // Follow LLVM (https://reviews.llvm.org/D25079) and set maximum page size
 // to 64 KB for ARM64 Linux builds.
 static constexpr intptr_t kElfPageSize = 64 * KB;
+#elif defined(DART_TARGET_OS_ANDROID) && defined(TARGET_ARCH_IS_64_BIT)
+static constexpr intptr_t kElfPageSize = 64 * KB;
 #else
 static constexpr intptr_t kElfPageSize = 16 * KB;
 #endif

diff --git a/runtime/vm/ffi_callback_metadata.cc b/runtime/vm/ffi_callback_metadata.cc
@@ -25,7 +25,7 @@ void FfiCallbackMetadata::EnsureStubPageLocked() {
   const Code& trampoline_code = StubCode::FfiCallbackTrampoline();
   const uword code_start = trampoline_code.EntryPoint();
   const uword code_end = code_start + trampoline_code.Size();
-  const uword page_start = code_start & kPageMask;
+  const uword page_start = code_start & ~(VirtualMemory::PageSize() - 1);
 
   ASSERT_LESS_OR_EQUAL((code_start - page_start) + trampoline_code.Size(),
                        RXMappingSize());

diff --git a/runtime/vm/ffi_callback_metadata.h b/runtime/vm/ffi_callback_metadata.h
@@ -184,6 +184,8 @@ class FfiCallbackMetadata {
   // get it as close as possible to avoid wasting memory.
 #if defined(DART_TARGET_OS_LINUX) && defined(TARGET_ARCH_ARM64)
   static constexpr intptr_t kPageSize = 64 * KB;
+#elif defined(DART_TARGET_OS_ANDROID) && defined(TARGET_ARCH_IS_64_BIT)
+  static constexpr intptr_t kPageSize = 64 * KB;
 #elif defined(DART_TARGET_OS_MACOS) && defined(TARGET_ARCH_ARM64)
   static constexpr intptr_t kPageSize = 16 * KB;
 #elif defined(DART_TARGET_OS_FUCHSIA)