From 8dbbf56aa104173e7defd9bce10603e6aa678810 Mon Sep 17 00:00:00 2001
From: Evgeniy Stepanov <eugeni.stepanov@gmail.com>
Date: Mon, 29 Aug 2016 23:42:34 +0000
Subject: [PATCH] [cfi] Export __cfi_check when linking with
 -fsanitize-cfi-cross-dso.

Multi-DSO CFI model requires every DSO to export a __cfi_check function.

llvm-svn: 280031
---
 clang/include/clang/Driver/SanitizerArgs.h |  1 +
 clang/lib/Driver/Tools.cpp                 |  5 +++++
 clang/test/Driver/sanitizer-ld.c           | 22 ++++++++++++++++++++++
 3 files changed, 28 insertions(+)

diff --git a/clang/include/clang/Driver/SanitizerArgs.h b/clang/include/clang/Driver/SanitizerArgs.h
index 7b293e0..59dd191 100644
--- a/clang/include/clang/Driver/SanitizerArgs.h
+++ b/clang/include/clang/Driver/SanitizerArgs.h
@@ -66,6 +66,7 @@ class SanitizerArgs {
   bool requiresPIE() const;
   bool needsUnwindTables() const;
   bool linkCXXRuntimes() const { return LinkCXXRuntimes; }
+  bool hasCrossDsoCfi() const { return CfiCrossDso; }
   void addArgs(const ToolChain &TC, const llvm::opt::ArgList &Args,
                llvm::opt::ArgStringList &CmdArgs, types::ID InputType) const;
 };
diff --git a/clang/lib/Driver/Tools.cpp b/clang/lib/Driver/Tools.cpp
index 5852ac1..464c424 100644
--- a/clang/lib/Driver/Tools.cpp
+++ b/clang/lib/Driver/Tools.cpp
@@ -3194,6 +3194,11 @@ static bool addSanitizerRuntimes(const ToolChain &TC, const ArgList &Args,
   // to be dynamic to be sure we export sanitizer interface functions.
   if (AddExportDynamic)
     CmdArgs.push_back("-export-dynamic");
+
+  const SanitizerArgs &SanArgs = TC.getSanitizerArgs();
+  if (SanArgs.hasCrossDsoCfi() && !AddExportDynamic)
+    CmdArgs.push_back("-export-dynamic-symbol=__cfi_check");
+
   return !StaticRuntimes.empty();
 }
 
diff --git a/clang/test/Driver/sanitizer-ld.c b/clang/test/Driver/sanitizer-ld.c
index 49561f4..d22815e 100644
--- a/clang/test/Driver/sanitizer-ld.c
+++ b/clang/test/Driver/sanitizer-ld.c
@@ -365,6 +365,7 @@
 // RUN:   | FileCheck --check-prefix=CHECK-CFI-CROSS-DSO-LINUX %s
 // CHECK-CFI-CROSS-DSO-LINUX: "{{.*}}ld{{(.exe)?}}"
 // CHECK-CFI-CROSS-DSO-LINUX: "-whole-archive" "{{[^"]*}}libclang_rt.cfi-x86_64.a" "-no-whole-archive"
+// CHECK-CFI-CROSS-DSO-LINUX: -export-dynamic
 
 // Cross-DSO CFI with diagnostics links just the CFI runtime.
 // RUN: %clang -fsanitize=cfi -fsanitize-cfi-cross-dso %s -### -o %t.o 2>&1 \
@@ -374,6 +375,7 @@
 // RUN:   | FileCheck --check-prefix=CHECK-CFI-CROSS-DSO-DIAG-LINUX %s
 // CHECK-CFI-CROSS-DSO-DIAG-LINUX: "{{.*}}ld{{(.exe)?}}"
 // CHECK-CFI-CROSS-DSO-DIAG-LINUX: "-whole-archive" "{{[^"]*}}libclang_rt.cfi_diag-x86_64.a" "-no-whole-archive"
+// CHECK-CFI-CROSS-DSO-DIAG-LINUX: -export-dynamic
 
 // RUN: %clangxx -fsanitize=address %s -### -o %t.o 2>&1 \
 // RUN:     -mmacosx-version-min=10.6 \
@@ -452,6 +454,26 @@
 // CHECK-SAFESTACK-ANDROID-AARCH64: "{{(.*[^-.0-9A-Z_a-z])?}}ld{{(.exe)?}}"
 // CHECK-SAFESTACK-ANDROID-AARCH64-NOT: libclang_rt.safestack
 
+// RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
+// RUN:     -target arm-linux-androideabi -fsanitize=cfi \
+// RUN:     --sysroot=%S/Inputs/basic_android_tree \
+// RUN:   | FileCheck --check-prefix=CHECK-CFI-ANDROID %s
+//
+// CHECK-CFI-ANDROID: "{{(.*[^-.0-9A-Z_a-z])?}}ld{{(.exe)?}}"
+// CHECK-CFI-ANDROID-NOT: libclang_rt.cfi
+// CHECK-CFI-ANDROID-NOT: __cfi_check
+
+// RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
+// RUN:     -target arm-linux-androideabi -fsanitize=cfi \
+// RUN:     -fsanitize-cfi-cross-dso \
+// RUN:     --sysroot=%S/Inputs/basic_android_tree \
+// RUN:   | FileCheck --check-prefix=CHECK-CROSSDSO-CFI-ANDROID %s
+//
+// CHECK-CROSSDSO-CFI-ANDROID: "{{(.*[^-.0-9A-Z_a-z])?}}ld{{(.exe)?}}"
+// CHECK-CROSSDSO-CFI-ANDROID-NOT: libclang_rt.cfi
+// CHECK-CROSSDSO-CFI-ANDROID: -export-dynamic-symbol=__cfi_check
+// CHECK-CROSSDSO-CFI-ANDROID-NOT: libclang_rt.cfi
+
 // RUN: %clang -fsanitize=undefined %s -### -o %t.o 2>&1 \
 // RUN:     -target x86_64-scei-ps4 \
 // RUN:     -shared \
-- 
2.7.4