[build] Fix Windows ASAN build to actually use ASAN.

Bug: https://github.com/dart-lang/sdk/issues/62263
Change-Id: I77a44aeff0a0685730ff3e5c897e338ddc5561a7
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/464781
Commit-Queue: Ryan Macnak <rmacnak@google.com>
Reviewed-by: Alexander Aprelev <aam@google.com>

build/config/BUILDCONFIG.gn

@@ -525,6 +525,12 @@ foreach(_target_type,
             ]
           }
         }
+        if (is_win && is_asan) {
+          if (!defined(data_deps)) {
+            data_deps = []
+          }
+          data_deps += [ "//build/config/compiler:copy_sanitizer_runtime" ]
+        }
       }
     }
   } else {

build/config/compiler/BUILD.gn

@@ -38,6 +38,13 @@ config("default_include_dirs") {
   ]
 }
 
+if (is_win && is_asan) {
+  copy("copy_sanitizer_runtime") {
+    sources = [ "//buildtools/win-x64/clang/lib/clang/22/lib/x86_64-pc-windows-msvc/clang_rt.asan_dynamic.dll" ]
+    outputs = [ "$root_out_dir/{{source_file_part}}" ]
+  }
+}
+
 # compiler ---------------------------------------------------------------------
 #
 # Base compiler configuration.
@@ -107,11 +114,38 @@ config("compiler") {
       ldflags += [ "-Wl,--fix-cortex-a53-843419" ]
     }
 
-    # Common options for AddressSanitizer, LeakSanitizer, ThreadSanitizer and
-    # MemorySanitizer
+    if (use_custom_libcxx) {
+      cflags_cc += [ "-nostdinc++" ]
+      include_dirs = [
+        "//buildtools/third_party/libc++/trunk/include",
+        "//buildtools/third_party/libc++abi/trunk/include",
+      ]
+    }
+  }
+
+  # Common options for AddressSanitizer, LeakSanitizer, ThreadSanitizer and
+  # MemorySanitizer
+  if (is_clang || !is_win) {
     if (is_asan) {
       cflags += [ "-fsanitize=address" ]
-      ldflags += [ "-fsanitize=address" ]
+      if (is_win) {
+        # Windows directly calls link.exe instead of the compiler driver when
+        # linking.  Hence, pass the runtime libraries instead of -fsanitize=address
+        # or -fsanitize=fuzzer.
+        _clang_lib_dir =
+            "//buildtools/win-x64/clang/lib/clang/22/lib/x86_64-pc-windows-msvc"
+        libs = [ "$_clang_lib_dir/clang_rt.asan_dynamic.lib" ]
+        ldflags += [ "-libpath:" + rebase_path("$_clang_lib_dir") ]
+        if (is_shared_library) {
+          ldflags += [ "-wholearchive:clang_rt.asan_dynamic_runtime_thunk.lib" ]
+          libs += [ "$_clang_lib_dir/clang_rt.asan_dynamic_runtime_thunk.lib" ]
+        } else {
+          ldflags += [ "-wholearchive:clang_rt.asan_static_runtime_thunk.lib" ]
+          libs += [ "$_clang_lib_dir/clang_rt.asan_static_runtime_thunk.lib" ]
+        }
+      } else {
+        ldflags += [ "-fsanitize=address" ]
+      }
     }
     if (is_hwasan && is_android && current_cpu == "arm64") {
       cflags += [ "-fsanitize=hwaddress" ]
@@ -156,14 +190,6 @@ config("compiler") {
         "@loader_path/../../../../buildtools/mac-$host_cpu/clang/lib/clang/22/lib/darwin",
       ]
     }
-
-    if (use_custom_libcxx) {
-      cflags_cc += [ "-nostdinc++" ]
-      include_dirs = [
-        "//buildtools/third_party/libc++/trunk/include",
-        "//buildtools/third_party/libc++abi/trunk/include",
-      ]
-    }
   }
 
   if (is_clang && is_debug) {
@@ -814,6 +840,12 @@ if (is_win) {
     # Warning: This changes C/C++ semantics of function pointer comparison.
     "/OPT:ICF",
   ]
+  if (is_clang) {
+    common_optimize_on_ldflags += [
+      # This interferes with ODR violation checks in ASAN.
+      "/OPT:NOLLDTAILMERGE",
+    ]
+  }
 } else {
   common_optimize_on_cflags = [
     # Don't emit the GCC version ident directives, they just end up in the

runtime/BUILD.gn

@@ -112,7 +112,7 @@ config("dart_precompiler_config") {
 
   # In our GN build rules we'll always compile AOT compiler & AOT runtime in
   # the same mode (TSAN or non-TSAN).
-  if (is_asan && !is_win) {
+  if (is_asan) {
     defines += [ "TARGET_USES_ADDRESS_SANITIZER" ]
   } else if (is_msan) {
     defines += [ "TARGET_USES_MEMORY_SANITIZER" ]

runtime/tests/vm/dart/asan/read_test.dart

@@ -59,7 +59,7 @@ main(List<String> arguments) {
   Expect.contains("READ of size 8", result.stderr);  //# uint64: ok
   Expect.contains("READ of size 4", result.stderr);  //# float32: ok
   Expect.contains("READ of size 8", result.stderr);  //# float64: ok
-  if (Platform.executable.contains("aotruntime")) {
+  if (Platform.executable.contains("aotruntime") && !Platform.isWindows) {
     Expect.contains("expectedFunction", result.stderr);
   }
 }

runtime/tests/vm/dart/asan/write_test.dart

@@ -59,7 +59,7 @@ main(List<String> arguments) {
   Expect.contains("WRITE of size 8", result.stderr);  //# uint64: ok
   Expect.contains("WRITE of size 4", result.stderr);  //# float32: ok
   Expect.contains("WRITE of size 8", result.stderr);  //# float64: ok
-  if (Platform.executable.contains("aotruntime")) {
+  if (Platform.executable.contains("aotruntime") && !Platform.isWindows) {
     Expect.contains("expectedFunction", result.stderr);
   }
 }

runtime/tests/vm/dart/msan/read_test.dart

@@ -59,7 +59,7 @@ main(List<String> arguments) {
   Expect.contains(", 8)", result.stderr);  //# uint64: ok
   Expect.contains(", 4)", result.stderr);  //# float32: ok
   Expect.contains(", 8)", result.stderr);  //# float64: ok
-  if (Platform.executable.contains("aotruntime")) {
+  if (Platform.executable.contains("aotruntime") && !Platform.isWindows) {
     Expect.contains("expectedFunction", result.stderr);
   }
 }