Add -fsanitize=fuzzer-no-link flag to the driver.

The flag will perform instrumentation necessary to the fuzzing,
but will NOT link libLLVMFuzzer.a library.
Necessary when modifying CFLAGS for projects which may produce
executables as well as a fuzzable target.

Differential Revision: https://reviews.llvm.org/D36600

llvm-svn: 310733

5 files changed, 15 insertions, 2 deletions

diff --git a/clang/include/clang/Basic/Sanitizers.def b/clang/include/clang/Basic/Sanitizers.def
index 28a92abf00b..d6df6171729 100644
--- a/clang/include/clang/Basic/Sanitizers.def
+++ b/clang/include/clang/Basic/Sanitizers.def
@@ -50,6 +50,9 @@ SANITIZER("memory", Memory)
 // libFuzzer
 SANITIZER("fuzzer", Fuzzer)
 
+// libFuzzer-required instrumentation, no linking.
+SANITIZER("fuzzer-no-link", FuzzerNoLink)
+
 // ThreadSanitizer
 SANITIZER("thread", Thread)
 
diff --git a/clang/lib/Driver/SanitizerArgs.cpp b/clang/lib/Driver/SanitizerArgs.cpp
index 2f12c6d4a5f..e411629ca42 100644
--- a/clang/lib/Driver/SanitizerArgs.cpp
+++ b/clang/lib/Driver/SanitizerArgs.cpp
@@ -32,7 +32,7 @@ enum : SanitizerMask {
   RequiresPIE = DataFlow,
   NeedsUnwindTables = Address | Thread | Memory | DataFlow,
   SupportsCoverage = Address | KernelAddress | Memory | Leak | Undefined |
-                     Integer | Nullability | DataFlow | Fuzzer,
+                     Integer | Nullability | DataFlow | Fuzzer | FuzzerNoLink,
   RecoverableByDefault = Undefined | Integer | Nullability,
   Unrecoverable = Unreachable | Return,
   LegacyFsanitizeRecoverMask = Undefined | Integer,
@@ -286,8 +286,11 @@ SanitizerArgs::SanitizerArgs(const ToolChain &TC,
       Add &= ~InvalidTrappingKinds;
       Add &= Supported;
 
-      // Enable coverage if the fuzzing flag is set.
       if (Add & Fuzzer)
+        Add |= FuzzerNoLink;
+
+      // Enable coverage if the fuzzing flag is set.
+      if (Add & FuzzerNoLink)
         CoverageFeatures |= CoverageTracePCGuard | CoverageIndirCall |
                             CoverageTraceCmp | CoveragePCTable;
 
diff --git a/clang/lib/Driver/ToolChains/Darwin.cpp b/clang/lib/Driver/ToolChains/Darwin.cpp
index 7f55d3ed7f3..f67e36ef635 100644
--- a/clang/lib/Driver/ToolChains/Darwin.cpp
+++ b/clang/lib/Driver/ToolChains/Darwin.cpp
@@ -2018,6 +2018,7 @@ SanitizerMask Darwin::getSupportedSanitizers() const {
   Res |= SanitizerKind::Address;
   Res |= SanitizerKind::Leak;
   Res |= SanitizerKind::Fuzzer;
+  Res |= SanitizerKind::FuzzerNoLink;
   if (isTargetMacOS()) {
     if (!isMacosxVersionLT(10, 9))
       Res |= SanitizerKind::Vptr;
diff --git a/clang/lib/Driver/ToolChains/Linux.cpp b/clang/lib/Driver/ToolChains/Linux.cpp
index 08a27fa7fed..1adf9f7070d 100644
--- a/clang/lib/Driver/ToolChains/Linux.cpp
+++ b/clang/lib/Driver/ToolChains/Linux.cpp
@@ -828,6 +828,7 @@ SanitizerMask Linux::getSupportedSanitizers() const {
   SanitizerMask Res = ToolChain::getSupportedSanitizers();
   Res |= SanitizerKind::Address;
   Res |= SanitizerKind::Fuzzer;
+  Res |= SanitizerKind::FuzzerNoLink;
   Res |= SanitizerKind::KernelAddress;
   Res |= SanitizerKind::Vptr;
   Res |= SanitizerKind::SafeStack;
diff --git a/clang/test/Driver/fuzzer.c b/clang/test/Driver/fuzzer.c
index 62ee06435c2..c0fc4b6f661 100644
--- a/clang/test/Driver/fuzzer.c
+++ b/clang/test/Driver/fuzzer.c
@@ -21,6 +21,11 @@
 // RUN: %clang -fsanitize=fuzzer %s -shared -o %t.so -### 2>&1 | FileCheck --check-prefixes=CHECK-NOLIB-SO %s
 // CHECK-NOLIB-SO-NOT: libLLVMFuzzer.a
 
+// Check that we don't link in libFuzzer when compiling with -fsanitize=fuzzer-no-link.
+// RUN: %clang -fsanitize=fuzzer-no-link %s -target x86_64-apple-darwin14 -### 2>&1 | FileCheck --check-prefixes=CHECK-NOLIB,CHECK-COV %s
+// CHECK-NOLIB-NOT: libLLVMFuzzer.a
+// CHECK-COV: -fsanitize-coverage-trace-pc-guard
+
 // RUN: %clang -fsanitize=fuzzer -fsanitize-coverage=trace-pc %s -### 2>&1 | FileCheck --check-prefixes=CHECK-MSG %s
 // CHECK-MSG-NOT: argument unused during compilation