[asan] A clang flag to enable ELF globals-gc.

This feature is subtly broken when the linker is gold 2.26 or
earlier. See the following bug for details:
  https://sourceware.org/bugzilla/show_bug.cgi?id=19002

Since the decision needs to be made at compilation time, we can not
test the linker version. The flag is off by default on ELF targets,
and on otherwise.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@302591 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/clang/Driver/Options.td b/include/clang/Driver/Options.td
index 31015228f362a11af0ad650b685d752f0ba7ba8c..d812bd8ec0326d60446ea42307c6aff149fb4ef9 100644 (file)
--- a/include/clang/Driver/Options.td
+++ b/include/clang/Driver/Options.td
@@ -827,6 +827,9 @@ def fno_sanitize_address_use_after_scope : Flag<["-"], "fno-sanitize-address-use
                                            Group<f_clang_Group>,
                                            Flags<[CoreOption, DriverOption]>,
                                            HelpText<"Disable use-after-scope detection in AddressSanitizer">;
+def fsanitize_address_globals_dead_stripping : Flag<["-"], "fsanitize-address-globals-dead-stripping">,
+                                        Group<f_clang_Group>,
+                                        HelpText<"Enable linker dead stripping of globals in AddressSanitizer">;
 def fsanitize_recover : Flag<["-"], "fsanitize-recover">, Group<f_clang_Group>;
 def fno_sanitize_recover : Flag<["-"], "fno-sanitize-recover">,
                            Flags<[CoreOption, DriverOption]>,

diff --git a/include/clang/Driver/SanitizerArgs.h b/include/clang/Driver/SanitizerArgs.h
index c7b3e8006dd5ddbb4b887b94bf9918b5c3f73c8d..a9645d463fa16ac833ff36b128201fab3b0f09cd 100644 (file)
--- a/include/clang/Driver/SanitizerArgs.h
+++ b/include/clang/Driver/SanitizerArgs.h
@@ -35,6 +35,7 @@ class SanitizerArgs {
   int AsanFieldPadding = 0;
   bool AsanSharedRuntime = false;
   bool AsanUseAfterScope = true;
+  bool AsanGlobalsDeadStripping = false;
   bool LinkCXXRuntimes = false;
   bool NeedPIE = false;
   bool Stats = false;

diff --git a/include/clang/Frontend/CodeGenOptions.def b/include/clang/Frontend/CodeGenOptions.def
index 7495ad808c991457d12acb2404f0eb5529c7f181..251441d38ff82ceb92f0c57f1101ffdf9a144f21 100644 (file)
--- a/include/clang/Frontend/CodeGenOptions.def
+++ b/include/clang/Frontend/CodeGenOptions.def
@@ -137,6 +137,8 @@ CODEGENOPT(StructPathTBAA    , 1, 0) ///< Whether or not to use struct-path TBAA
 CODEGENOPT(SaveTempLabels    , 1, 0) ///< Save temporary labels.
 CODEGENOPT(SanitizeAddressUseAfterScope , 1, 0) ///< Enable use-after-scope detection
                                                 ///< in AddressSanitizer
+CODEGENOPT(SanitizeAddressGlobalsDeadStripping, 1, 0) ///< Enable linker dead stripping
+                                                      ///< of globals in AddressSanitizer
 CODEGENOPT(SanitizeMemoryTrackOrigins, 2, 0) ///< Enable tracking origins in
                                              ///< MemorySanitizer
 CODEGENOPT(SanitizeMemoryUseAfterDtor, 1, 0) ///< Enable use-after-delete detection

diff --git a/lib/CodeGen/BackendUtil.cpp b/lib/CodeGen/BackendUtil.cpp
index 0d96f2efa60a96d96ee5ccffe60bfedaf4899889..51c21c9f25d540e73670c17e894c13082e7b6df2 100644 (file)
--- a/lib/CodeGen/BackendUtil.cpp
+++ b/lib/CodeGen/BackendUtil.cpp
@@ -194,6 +194,8 @@ static void addSanitizerCoveragePass(const PassManagerBuilder &Builder,
 // where this is not a factor). Also, on ELF this feature requires an assembler
 // extension that only works with -integrated-as at the moment.
 static bool asanUseGlobalsGC(const Triple &T, const CodeGenOptions &CGOpts) {
+  if (!CGOpts.SanitizeAddressGlobalsDeadStripping)
+    return false;
   switch (T.getObjectFormat()) {
   case Triple::MachO:
   case Triple::COFF:

diff --git a/lib/Driver/SanitizerArgs.cpp b/lib/Driver/SanitizerArgs.cpp
index b6fc9e9ba4fa7bb716d591e5fb2efd41c7efce99..9ab2e176845cfa516693059a6db5451258b5fc1a 100644 (file)
--- a/lib/Driver/SanitizerArgs.cpp
+++ b/lib/Driver/SanitizerArgs.cpp
@@ -566,6 +566,13 @@ SanitizerArgs::SanitizerArgs(const ToolChain &TC,
     AsanUseAfterScope = Args.hasFlag(
         options::OPT_fsanitize_address_use_after_scope,
         options::OPT_fno_sanitize_address_use_after_scope, AsanUseAfterScope);
+
+    // 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
+    AsanGlobalsDeadStripping =
+        !TC.getTriple().isOSBinFormatELF() ||
+        Args.hasArg(options::OPT_fsanitize_address_globals_dead_stripping);
   } else {
     AsanUseAfterScope = false;
   }
@@ -717,6 +724,9 @@ void SanitizerArgs::addArgs(const ToolChain &TC, const llvm::opt::ArgList &Args,
   if (AsanUseAfterScope)
     CmdArgs.push_back("-fsanitize-address-use-after-scope");
 
+  if (AsanGlobalsDeadStripping)
+    CmdArgs.push_back("-fsanitize-address-globals-dead-stripping");
+
   // MSan: Workaround for PR16386.
   // ASan: This is mainly to help LSan with cases such as
   // https://code.google.com/p/address-sanitizer/issues/detail?id=373

diff --git a/lib/Frontend/CompilerInvocation.cpp b/lib/Frontend/CompilerInvocation.cpp
index 96854b8fbc1abe8dbbc405d0971e3c610dd2aedb..51147b6f9499785f19aad725153522d5817f07aa 100644 (file)
--- a/lib/Frontend/CompilerInvocation.cpp
+++ b/lib/Frontend/CompilerInvocation.cpp
@@ -778,6 +778,8 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
     Opts.SanitizeAddressUseAfterScope =
         A->getOption().getID() == OPT_fsanitize_address_use_after_scope;
   }
+  Opts.SanitizeAddressGlobalsDeadStripping =
+      Args.hasArg(OPT_fsanitize_address_globals_dead_stripping);
   Opts.SSPBufferSize =
       getLastArgIntValue(Args, OPT_stack_protector_buffer_size, 8, Diags);
   Opts.StackRealignment = Args.hasArg(OPT_mstackrealign);

diff --git a/test/CodeGen/asan-globals-gc.cpp b/test/CodeGen/asan-globals-gc.cpp
index 6d64f41dda8dd86e319de274b0596c965134f963..58ce5f067563837a01fb0b36d4969683d8c649a9 100644 (file)
--- a/test/CodeGen/asan-globals-gc.cpp
+++ b/test/CodeGen/asan-globals-gc.cpp
@@ -1,5 +1,16 @@
-// RUN: %clang_cc1 -fsanitize=address -emit-llvm -o - -triple x86_64-windows-msvc %s | FileCheck %s --check-prefix=WITH-GC
-// RUN: %clang_cc1 -fsanitize=address -emit-llvm -o - -triple x86_64-windows-msvc -fdata-sections %s | FileCheck %s --check-prefix=WITH-GC
+// RUN: %clang_cc1 -fsanitize=address -fsanitize-address-globals-dead-stripping -emit-llvm -o - -triple x86_64-linux %s | FileCheck %s --check-prefix=WITHOUT-GC
+// RUN: %clang_cc1 -fsanitize=address -fsanitize-address-globals-dead-stripping -fdata-sections -emit-llvm -o - -triple x86_64-linux %s | FileCheck %s --check-prefix=WITH-GC
+// RUN: %clang_cc1 -fsanitize=address -fsanitize-address-globals-dead-stripping -fno-integrated-as -fdata-sections -emit-llvm -o - -triple x86_64-linux %s | FileCheck %s --check-prefix=WITHOUT-GC
+// RUN: %clang_cc1 -fsanitize=address -fsanitize-address-globals-dead-stripping -fno-integrated-as -emit-llvm -o - -triple x86_64-linux %s | FileCheck %s --check-prefix=WITHOUT-GC
+// RUN: %clang_cc1 -fsanitize=address -fdata-sections -emit-llvm -o - -triple x86_64-linux %s | FileCheck %s --check-prefix=WITHOUT-GC
+
+// RUN: %clang_cc1 -fsanitize=address -fsanitize-address-globals-dead-stripping -fno-data-sections -emit-llvm -o - -triple x86_64-windows-msvc %s | FileCheck %s --check-prefix=WITH-GC
+// RUN: %clang_cc1 -fsanitize=address -fsanitize-address-globals-dead-stripping -fdata-sections -emit-llvm -o - -triple x86_64-windows-msvc %s | FileCheck %s --check-prefix=WITH-GC
+// RUN: %clang_cc1 -fsanitize=address -fdata-sections -emit-llvm -o - -triple x86_64-windows-msvc %s | FileCheck %s --check-prefix=WITHOUT-GC
+
+// RUN: %clang_cc1 -fsanitize=address -fsanitize-address-globals-dead-stripping -fno-data-sections -emit-llvm -o - -triple x86_64-apple-macosx11 %s | FileCheck %s --check-prefix=WITH-GC
+// RUN: %clang_cc1 -fsanitize=address -fsanitize-address-globals-dead-stripping -fdata-sections -emit-llvm -o - -triple x86_64-apple-macosx11 %s | FileCheck %s --check-prefix=WITH-GC
+// RUN: %clang_cc1 -fsanitize=address -fdata-sections -emit-llvm -o - -triple x86_64-apple-macosx11 %s | FileCheck %s --check-prefix=WITHOUT-GC
 
 int global;
 

diff --git a/test/Driver/fsanitize.c b/test/Driver/fsanitize.c
index bce55ac065ac0b8889692804b9de57d3e2646fd4..2b1789b60f8ed0a793b14a5f438c3357735f0aeb 100644 (file)
--- a/test/Driver/fsanitize.c
+++ b/test/Driver/fsanitize.c
@@ -126,6 +126,13 @@
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=address %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-ASAN-WITHOUT-USE-AFTER-SCOPE
 // CHECK-ASAN-WITHOUT-USE-AFTER-SCOPE: -cc1{{.*}}address-use-after-scope
 
+// RUN: %clang -target x86_64-linux-gnu -fsanitize=address -fsanitize-address-globals-dead-stripping %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-ASAN-GLOBALS
+// RUN: %clang -target x86_64-linux-gnu -fsanitize=address %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-NO-ASAN-GLOBALS
+// RUN: %clang_cl -target x86_64-windows-msvc -fsanitize=address -fsanitize-address-globals-dead-stripping -### -- %s 2>&1 | FileCheck %s --check-prefix=CHECK-ASAN-GLOBALS
+// RUN: %clang_cl -target x86_64-windows-msvc -fsanitize=address -### -- %s 2>&1 | FileCheck %s --check-prefix=CHECK-ASAN-GLOBALS
+// 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-memory-track-origins -pie %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-ONLY-TRACK-ORIGINS
 // CHECK-ONLY-TRACK-ORIGINS: warning: argument unused during compilation: '-fsanitize-memory-track-origins'