[PATCH] D17360: [cfi] Fix handling of sanitize trap/recover flags in the cross-DSO CFI mode.

[Evgeniy Stepanov via cfe-commits]

eugenis created this revision.
eugenis added reviewers: pcc, krasin.
eugenis added a subscriber: cfe-commits.
eugenis set the repository for this revision to rL LLVM.

In the cross-DSO CFI mode a module may be asked to handle any type of
CFI error, even if the module itself is not checked for that type of
error. Therefore, trap/recover flags should be preserved all CFI
checkers and not just for the ones that are enabled.

This fixes a linker error caused by the missing cfi_diag runtime
library with certain combinations of CFI flags (see the new test
case).


Repository:
  rL LLVM

http://reviews.llvm.org/D17360

Files:
  lib/Driver/SanitizerArgs.cpp
  test/Driver/fsanitize.c

Index: test/Driver/fsanitize.c
===================================================================
--- test/Driver/fsanitize.c
+++ test/Driver/fsanitize.c
@@ -272,6 +272,21 @@
 // CHECK-CFI-NO-CROSS-DSO: -emit-llvm-bc
 // CHECK-CFI-NO-CROSS-DSO-NOT: -fsanitize-cfi-cross-dso
 
+// In the non-cross-dso CFI mode, -fsanitize-trap only appears for enabled CFI checkers.
+// RUN: %clang -target x86_64-linux-gnu -fsanitize=cfi-vcall -c %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-CFI-VCALL-TRAP
+// CHECK-CFI-VCALL-TRAP: "-fsanitize=cfi-vcall" "-fsanitize-trap=cfi-vcall"
+
+// RUN: %clang -target x86_64-linux-gnu -fsanitize=cfi-vcall -fno-sanitize-trap=cfi-vcall -c %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-CFI-VCALL-NO-TRAP
+// CHECK-CFI-VCALL-NO-TRAP: "-fsanitize=cfi-vcall"
+// CHECK-CFI-VCALL-NO-TRAP-NOT: -fsanitize-trap=
+
+// In the cross-dso CFI mode, -fsanitize-trap appears for all CFI checkers.
+// RUN: %clang -target x86_64-linux-gnu -fsanitize=cfi-vcall -fsanitize-cfi-cross-dso -flto -c %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-CFI-CROSS-DSO-VCALL-TRAP
+// CHECK-CFI-CROSS-DSO-VCALL-TRAP: "-fsanitize=cfi-vcall" "-fsanitize-trap=cfi-derived-cast,cfi-icall,cfi-unrelated-cast,cfi-nvcall,cfi-vcall"
+
+// RUN: %clang -target x86_64-linux-gnu -fsanitize=cfi-vcall -fno-sanitize-trap=cfi-vcall -fsanitize-cfi-cross-dso -flto -c %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-CFI-CROSS-DSO-VCALL-NO-TRAP
+// CHECK-CFI-CROSS-DSO-VCALL-NO-TRAP: "-fsanitize=cfi-vcall" "-fsanitize-trap=cfi-derived-cast,cfi-icall,cfi-unrelated-cast,cfi-nvcall"
+
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=cfi -fsanitize-stats -flto -c %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-CFI-STATS
 // CHECK-CFI-STATS: -fsanitize-stats
 
Index: lib/Driver/SanitizerArgs.cpp
===================================================================
--- lib/Driver/SanitizerArgs.cpp
+++ lib/Driver/SanitizerArgs.cpp
@@ -166,11 +166,11 @@
 }
 
 bool SanitizerArgs::needsCfiRt() const {
-  return !(Sanitizers.Mask & CFI & ~TrapSanitizers.Mask) && CfiCrossDso;
+  return !(CFI & ~TrapSanitizers.Mask) && CfiCrossDso;
 }
 
 bool SanitizerArgs::needsCfiDiagRt() const {
-  return (Sanitizers.Mask & CFI & ~TrapSanitizers.Mask) && CfiCrossDso;
+  return (CFI & ~TrapSanitizers.Mask) && CfiCrossDso;
 }
 
 bool SanitizerArgs::requiresPIE() const {
@@ -361,10 +361,27 @@
                                             << DeprecatedReplacement;
     }
   }
-  RecoverableKinds &= Kinds;
-  RecoverableKinds &= ~Unrecoverable;
 
-  TrappingKinds &= Kinds;
+  if (AllAddedKinds & CFI) {
+    CfiCrossDso = Args.hasFlag(options::OPT_fsanitize_cfi_cross_dso,
+                               options::OPT_fno_sanitize_cfi_cross_dso, false);
+    // Without PIE, external function address may resolve to a PLT record, which
+    // can not be verified by the target module.
+    NeedPIE |= CfiCrossDso;
+  }
+
+  // In the cross-DSO CFI mode a module may be asked to handle any type of CFI
+  // error, even if the module itself is not checked for that type of error.
+  // Therefore, trap/recover flags should be preserved all CFI checkers.
+  if (CfiCrossDso) {
+    TrappingKinds &= (Kinds | CFI);
+    RecoverableKinds &= (Kinds | CFI);
+  } else {
+    TrappingKinds &= Kinds;
+    RecoverableKinds &= Kinds;
+  }
+
+  RecoverableKinds &= ~Unrecoverable;
 
   // Setup blacklist files.
   // Add default blacklist from resource directory.
@@ -424,14 +441,6 @@
                  TC.getTriple().getArch() == llvm::Triple::x86_64);
   }
 
-  if (AllAddedKinds & CFI) {
-    CfiCrossDso = Args.hasFlag(options::OPT_fsanitize_cfi_cross_dso,
-                               options::OPT_fno_sanitize_cfi_cross_dso, false);
-    // Without PIE, external function address may resolve to a PLT record, which
-    // can not be verified by the target module.
-    NeedPIE |= CfiCrossDso;
-  }
-
   Stats = Args.hasFlag(options::OPT_fsanitize_stats,
                        options::OPT_fno_sanitize_stats, false);
 


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