Add AddressSanitizer support to fibers.

.travis.yml

@@ -10,7 +10,7 @@ matrix:
     #  env: LLVM_VERSION=7.0.1 OPTS="-DBUILD_SHARED_LIBS=ON"
     - os: linux
       d: ldc-beta
-      env: LLVM_VERSION=6.0.1 OPTS="-DBUILD_SHARED_LIBS=OFF -DLIB_SUFFIX=64"
+      env: LLVM_VERSION=6.0.1 OPTS="-DBUILD_SHARED_LIBS=OFF -DLIB_SUFFIX=64 -DRT_SUPPORT_SANITIZERS=ON"
     - os: linux
       d: ldc
       env: LLVM_VERSION=5.0.2 OPTS="-DBUILD_SHARED_LIBS=ON -DLIB_SUFFIX=64"

runtime/CMakeLists.txt

@@ -47,9 +47,15 @@ set(LD_FLAGS              ""                                  CACHE STRING "Runt
 set(C_SYSTEM_LIBS         AUTO                                CACHE STRING "C system libraries for linking shared libraries and test runners, separated by ';'")
 set(TARGET_SYSTEM         AUTO                                CACHE STRING "Target OS/toolchain for cross-compilation (e.g., 'Linux;UNIX', 'Darwin;APPLE;UNIX', 'Windows;MSVC')")
 set(LDC_TARGET_PRESET     ""                                  CACHE STRING "Use a preset target configuration for cross-compilation, by passing format OS-arch (e.g., 'Linux-arm', 'Mac-x64', 'Windows-aarch64', 'Android-x86')")
+set(RT_SUPPORT_SANITIZERS OFF                                 CACHE BOOL   "Build runtime libraries with sanitizer support (e.g. for AddressSanitizer)")
 
 set(CMAKE_INSTALL_LIBDIR ${CMAKE_INSTALL_PREFIX}/lib${LIB_SUFFIX})
 
+if (RT_SUPPORT_SANITIZERS)
+    message(STATUS "Building runtime libraries with sanitizer support")
+    set(D_FLAGS "${D_FLAGS};-d-version=SupportSanitizers")
+endif()
+
 # Find gnu make, use specific version first (BSD) and fall back to default 'make' (LINUX)
 find_program(GNU_MAKE_BIN NAMES gmake gnumake make)
 if ("${GNU_MAKE_BIN}" STREQUAL "")

tests/lit.site.cfg.in

@@ -27,6 +27,7 @@ config.gnu_make_bin        = "@GNU_MAKE_BIN@"
 config.ldc_host_arch       = "@LDC_HOST_ARCH@"
 config.ldc_with_lld        = "@LDC_WITH_LLD@" == "ON"
 config.spirv_enabled       = @LLVM_SPIRV_FOUND@ +0 # LLVM_SPIRV_FOUND is blank if not set
+config.rt_supports_sanitizers = "@RT_SUPPORT_SANITIZERS@" == "ON"
 
 config.name = 'LDC'
 
@@ -92,6 +93,9 @@ for t in config.llvm_targetsstr.split(';'):
 if config.spirv_enabled:
     config.available_features.add('target_SPIRV')
 
+if config.rt_supports_sanitizers:
+    config.available_features.add('RTSupportsSanitizers')
+
 # Add specific features for Windows x86/x64 testing
 if (platform.system() == 'Windows') and (config.default_target_bits == 32):
     config.available_features.add('Windows_x86')

tests/sanitizers/asan_fiber.d

@@ -0,0 +1,40 @@
+// AddressSanitizer: Test stack overflow detection of an array on a fiber's local stack.
+
+// REQUIRES: ASan, RTSupportsSanitizers
+
+// RUN: %ldc -g -fsanitize=address %s -of=%t%exe                             &&  not %t%exe 2>&1 | FileCheck %s
+// RUN: %ldc -g -fsanitize=address %s -of=%t%exe -d-version=BAD_AFTER_YIELD  &&  not %t%exe 2>&1 | FileCheck %s
+
+import core.thread;
+
+// Note: the ordering of `foo` and `prefoo` is intentional to ease FileCheck checking line numbers,
+// because of the order in which ASan reports the stack buffer overflow.
+
+void foo(int* ptr)
+{
+    version (BAD_AFTER_YIELD)
+        Fiber.yield();
+
+    // CHECK: stack-buffer-overflow
+    // CHECK: WRITE of size 4
+    // CHECK-NEXT: #0 {{.*}} in {{.*foo.*}} {{.*}}asan_fiber.d:[[@LINE+1]]
+    ptr[10] = 1;
+
+}
+
+// CHECK-NOT: wild pointer
+// CHECK: Address {{.*}} is located in stack of
+// CHECK-NEXT: #0 {{.*}} in {{.*prefoo.*}} {{.*}}asan_fiber.d:[[@LINE+1]]
+void prefoo()
+{
+    int[10] a;
+    foo(&a[0]);
+}
+
+void main()
+{
+    auto fib = new Fiber(&prefoo);
+    fib.call();
+    version (BAD_AFTER_YIELD)
+        fib.call();
+}

tests/sanitizers/asan_fiber_main.d

@@ -0,0 +1,43 @@
+// AddressSanitizer: Test stack overflow detection inside a fiber of an array on main's stack.
+
+// REQUIRES: ASan, RTSupportsSanitizers
+
+// RUN: %ldc -g -fsanitize=address %s -of=%t1%exe                              &&  not %t1%exe  2>&1 | FileCheck %s
+// RUN: %ldc -g -fsanitize=address %s -of=%t22%exe -d-version=BAD_AFTER_YIELD  &&  not %t22%exe 2>&1 | FileCheck %s
+
+// Test with fake stack enabled
+// RUN: env %env_asan_opts=detect_stack_use_after_return=true not %t1%exe  2>&1 | FileCheck %s --check-prefix=FAKESTACK
+// RUN: env %env_asan_opts=detect_stack_use_after_return=true not %t22%exe 2>&1 | FileCheck %s --check-prefix=FAKESTACK
+
+import core.thread;
+
+void foo(int* arr)
+{
+    version (BAD_AFTER_YIELD)
+        Fiber.yield();
+
+    // CHECK: stack-buffer-overflow
+    // CHECK: WRITE of size 4
+    // CHECK-NEXT: #0 {{.*}} in {{.*foo.*}} {{.*}}asan_fiber_main.d:[[@LINE+1]]
+    arr[10] = 1; // out-of-bounds write
+}
+
+// Without fake stack, ASan only keeps track of the current stack and thus reports
+// the bad memory location as a "wild pointer".
+// But with fake stack enabled we get something much better:
+// FAKESTACK: Address {{.*}} is located in stack of
+// FAKESTACK: #0 {{.*}} in {{.*main.*}} {{.*}}asan_fiber_main.d:[[@LINE+1]]
+void main()
+{
+    int[10] a;
+    int b;
+
+    // Use an extra variable instead of passing `&a[0]` directly to `foo`.
+    // This is to keep `a` on the stack: `ptr` may be heap allocated because
+    // it is used in the lambda (delegate).
+    int* ptr = &a[0];
+    auto fib = new Fiber(() => foo(ptr));
+    fib.call();
+    version (BAD_AFTER_YIELD)
+        fib.call();
+}

tests/sanitizers/lit.local.cfg

@@ -19,7 +19,11 @@ if 'ASan' in config.available_features:
     # On Darwin, ASan defaults to `abort_on_error=1`, which would make tests run
     # much slower. Let's override this and run lit tests with 'abort_on_error=0'.
     # Also, make sure we do not overwhelm the syslog while testing.
-    config.environment['ASAN_OPTIONS'] = 'abort_on_error=0:log_to_syslog=0'
+    default_asan_options = 'abort_on_error=0:log_to_syslog=0'
+    config.environment['ASAN_OPTIONS'] = default_asan_options
+    # And add a convenience substitution so we can append to the default ASAN_OPTIONS
+    config.substitutions.append(('%env_asan_opts=',
+                                 'env ASAN_OPTIONS=' + default_asan_options + ':'))
 
 # Note: To get line numbers in stack traces on Darwin, we need to run dsymutil on the binary,
 # because llvm-symbolizer does not look at the object file for debug info.