[asan][clang] Add flag to outline instrumentation

Summary This option can be used to reduce the size of the
binary. The trade-off in this case would be the run-time
performance.

Reviewed By: vitalybuka

Differential Revision: https://reviews.llvm.org/D105726

clang/docs/AddressSanitizer.rst

@@ -276,6 +276,18 @@ library name in the symbolized stack trace of the leak report. See
 <https://github.com/google/sanitizers/wiki/AddressSanitizerLeakSanitizer#suppressions>`_
 for more details.
 
+Code generation control
+=======================
+
+Instrumentation code outlining
+------------------------------
+
+By default AddressSanitizer inlines the instumentation code to improve the
+run-time performance, which leads to increased binary size. Using the
+(clang flag ``-fsanitize-address-outline-instrumentation` default: ``false``)
+flag forces all code instumentation to be outlined, which reduces the size
+of the binary, but also reduces the run-time performace.
+
 Limitations
 ===========
 

clang/docs/UsersManual.rst

@@ -1649,6 +1649,14 @@ are listed below.
    Enable simple code coverage in addition to certain sanitizers.
    See :doc:`SanitizerCoverage` for more details.
 
+**-f[no-]sanitize-address-outline-instrumentation**
+
+   Controls how address sanitizer code is generated. If enabled will always use
+   a function call instead of inlining the code. Turning this option on could
+   reduce the binary size, but might result in a worse run-time performance.
+
+   See :doc: `AddressSanitizer` for more details.
+
 **-f[no-]sanitize-stats**
 
    Enable simple statistics gathering for the enabled sanitizers.

clang/include/clang/Driver/Options.td

@@ -1558,6 +1558,12 @@ def fno_sanitize_memory_track_origins : Flag<["-"], "fno-sanitize-memory-track-o
                                         Group<f_clang_Group>,
                                         Flags<[CoreOption, NoXarchOption]>,
                                         HelpText<"Disable origins tracking in MemorySanitizer">;
+def fsanitize_address_outline_instrumentation : Flag<["-"], "fsanitize-address-outline-instrumentation">,
+                                                Group<f_clang_Group>,
+                                                HelpText<"Always generate function calls for address sanitizer instrumentation">;
+def fno_sanitize_address_outline_instrumentation : Flag<["-"], "fno-sanitize-address-outline-instrumentation">,
+                                                   Group<f_clang_Group>,
+                                                   HelpText<"Use default code inlining logic for the address sanitizer">;
 def fsanitize_hwaddress_experimental_aliasing
   : Flag<["-"], "fsanitize-hwaddress-experimental-aliasing">,
     Group<f_clang_Group>,

clang/include/clang/Driver/SanitizerArgs.h

@@ -44,6 +44,7 @@ class SanitizerArgs {
   bool AsanUseOdrIndicator = false;
   bool AsanInvalidPointerCmp = false;
   bool AsanInvalidPointerSub = false;
+  bool AsanOutlineInstrumentation = false;
   llvm::AsanDtorKind AsanDtorKind = llvm::AsanDtorKind::Invalid;
   std::string HwasanAbi;
   bool LinkRuntimes = true;

clang/lib/Driver/SanitizerArgs.cpp

@@ -805,6 +805,11 @@ SanitizerArgs::SanitizerArgs(const ToolChain &TC,
         options::OPT_fno_sanitize_address_poison_custom_array_cookie,
         AsanPoisonCustomArrayCookie);
 
+    AsanOutlineInstrumentation =
+        Args.hasFlag(options::OPT_fsanitize_address_outline_instrumentation,
+                     options::OPT_fno_sanitize_address_outline_instrumentation,
+                     AsanOutlineInstrumentation);
+
     // As a workaround for a bug in gold 2.26 and earlier, dead stripping of
     // globals in ASan is disabled by default on ELF targets.
     // See https://sourceware.org/bugzilla/show_bug.cgi?id=19002
@@ -1118,6 +1123,11 @@ void SanitizerArgs::addArgs(const ToolChain &TC, const llvm::opt::ArgList &Args,
     CmdArgs.push_back("-asan-detect-invalid-pointer-sub");
   }
 
+  if (AsanOutlineInstrumentation) {
+    CmdArgs.push_back("-mllvm");
+    CmdArgs.push_back("-asan-instrumentation-with-call-threshold=0");
+  }
+
   // Only pass the option to the frontend if the user requested,
   // otherwise the frontend will just use the codegen default.
   if (AsanDtorKind != llvm::AsanDtorKind::Invalid) {

clang/test/CodeGen/asan-use-callbacks.cpp

@@ -0,0 +1,12 @@
+// RUN: %clang -S -fsanitize=address -emit-llvm -o - -fsanitize=address %s \
+// RUN:     | FileCheck %s --check-prefixes=CHECK-NO-OUTLINE
+// RUN: %clang -S -fsanitize=address -emit-llvm -o - -fsanitize=address %s \
+// RUN:     -fsanitize-address-outline-instrumentation \
+// RUN:     | FileCheck %s --check-prefixes=CHECK-OUTLINE
+
+// CHECK-NO-OUTLINE-NOT: call{{.*}}@__asan_load4
+// CHECK-OUTLINE: call{{.*}}@__asan_load4
+
+int deref(int *p) {
+  return *p;
+}

clang/test/Driver/fsanitize.c

@@ -247,6 +247,20 @@
 // CHECK-ASAN-GLOBALS: -cc1{{.*}}-fsanitize-address-globals-dead-stripping
 // CHECK-NO-ASAN-GLOBALS-NOT: -cc1{{.*}}-fsanitize-address-globals-dead-stripping
 
+// RUN: %clang -target x86_64-linux-gnu -fsanitize-address-outline-instrumentation %s -### 2>&1 | \
+// RUN:     FileCheck %s --check-prefix=CHECK-ASAN-OUTLINE-WARN
+// CHECK-ASAN-OUTLINE-WARN: warning: argument unused during compilation: '-fsanitize-address-outline-instrumentation'
+// RUN: %clang -target x86_64-linux-gnu -fsanitize=address -fsanitize-address-outline-instrumentation %s -### 2>&1 | \
+// RUN:     FileCheck %s --check-prefix=CHECK-ASAN-OUTLINE-OK
+// RUN: %clang -target x86_64-linux-gnu -fsanitize=address -fno-sanitize-address-outline-instrumentation -fsanitize-address-outline-instrumentation %s -### 2>&1 | \
+// RUN:     FileCheck %s --check-prefix=CHECK-ASAN-OUTLINE-OK
+// CHECK-ASAN-OUTLINE-OK: "-mllvm" "-asan-instrumentation-with-call-threshold=0"
+// RUN: %clang -target x86_64-linux-gnu -fsanitize=address -fno-sanitize-address-outline-instrumentation %s -### 2>&1 | \
+// RUN:     FileCheck %s --check-prefix=CHECK-NO-CHECK-ASAN-CALLBACK
+// RUN: %clang -target x86_64-linux-gnu -fsanitize=address -fsanitize-address-outline-instrumentation -fno-sanitize-address-outline-instrumentation %s -### 2>&1 | \
+// RUN:     FileCheck %s --check-prefix=CHECK-NO-CHECK-ASAN-CALLBACK
+// CHECK-NO-CHECK-ASAN-CALLBACK-NOT: "-mllvm" "-asan-instrumentation-with-call-threshold=0"
+
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=address -fsanitize-address-use-odr-indicator %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-ASAN-ODR-INDICATOR
 // RUN: %clang_cl --target=x86_64-windows -fsanitize=address -fsanitize-address-use-odr-indicator -### -- %s 2>&1 | FileCheck %s --check-prefix=CHECK-ASAN-ODR-INDICATOR
 // CHECK-ASAN-ODR-INDICATOR: -cc1{{.*}}-fsanitize-address-use-odr-indicator