Reland "Add sanitizer metadata attributes to clang IR gen."

RE-LAND (reverts a revert):
This reverts commit 8e1f47b.

This patch adds generation of sanitizer metadata attributes (which were
added in D126100) to the clang frontend.

We still currently generate the llvm.asan.globals that's consumed by
the IR pass, but the plan is to eventually migrate off of that onto
purely debuginfo and these IR attributes.

Reviewed By: vitalybuka, kstoimenov

Differential Revision: https://reviews.llvm.org/D126929

clang/lib/CodeGen/CodeGenModule.cpp

@@ -2760,21 +2760,14 @@ bool CodeGenModule::isInNoSanitizeList(SanitizerMask Kind, llvm::Function *Fn,
   return false;
 }
 
-bool CodeGenModule::isInNoSanitizeList(llvm::GlobalVariable *GV,
+bool CodeGenModule::isInNoSanitizeList(SanitizerMask Kind,
+                                       llvm::GlobalVariable *GV,
                                        SourceLocation Loc, QualType Ty,
                                        StringRef Category) const {
-  // For now globals can be ignored only in ASan and KASan.
-  const SanitizerMask EnabledAsanMask =
-      LangOpts.Sanitize.Mask &
-      (SanitizerKind::Address | SanitizerKind::KernelAddress |
-       SanitizerKind::HWAddress | SanitizerKind::KernelHWAddress |
-       SanitizerKind::MemTag);
-  if (!EnabledAsanMask)
-    return false;
   const auto &NoSanitizeL = getContext().getNoSanitizeList();
-  if (NoSanitizeL.containsGlobal(EnabledAsanMask, GV->getName(), Category))
+  if (NoSanitizeL.containsGlobal(Kind, GV->getName(), Category))
     return true;
-  if (NoSanitizeL.containsLocation(EnabledAsanMask, Loc, Category))
+  if (NoSanitizeL.containsLocation(Kind, Loc, Category))
     return true;
   // Check global type.
   if (!Ty.isNull()) {
@@ -2786,7 +2779,7 @@ bool CodeGenModule::isInNoSanitizeList(llvm::GlobalVariable *GV,
     // Only record types (classes, structs etc.) are ignored.
     if (Ty->isRecordType()) {
       std::string TypeStr = Ty.getAsString(getContext().getPrintingPolicy());
-      if (NoSanitizeL.containsType(EnabledAsanMask, TypeStr, Category))
+      if (NoSanitizeL.containsType(Kind, TypeStr, Category))
         return true;
     }
   }

clang/lib/CodeGen/CodeGenModule.h

@@ -1314,8 +1314,9 @@ class CodeGenModule : public CodeGenTypeCache {
   bool isInNoSanitizeList(SanitizerMask Kind, llvm::Function *Fn,
                           SourceLocation Loc) const;
 
-  bool isInNoSanitizeList(llvm::GlobalVariable *GV, SourceLocation Loc,
-                          QualType Ty, StringRef Category = StringRef()) const;
+  bool isInNoSanitizeList(SanitizerMask Kind, llvm::GlobalVariable *GV,
+                          SourceLocation Loc, QualType Ty,
+                          StringRef Category = StringRef()) const;
 
   /// Imbue XRay attributes to a function, applying the always/never attribute
   /// lists in the process. Returns true if we did imbue attributes this way,

clang/lib/CodeGen/SanitizerMetadata.cpp

@@ -22,19 +22,66 @@ using namespace CodeGen;
 
 SanitizerMetadata::SanitizerMetadata(CodeGenModule &CGM) : CGM(CGM) {}
 
+// TODO(hctim): Can be removed when we migrate off of llvm.asan.globals. This
+// prevents llvm.asan.globals from being emitted for
+// __attribute__((disable_sanitizer_instrumentation)) and uses of
+// -fsanitize-ignorelist when a sanitizer isn't enabled.
 static bool isAsanHwasanOrMemTag(const SanitizerSet &SS) {
   return SS.hasOneOf(SanitizerKind::Address | SanitizerKind::KernelAddress |
-                     SanitizerKind::HWAddress | SanitizerKind::KernelHWAddress |
-                     SanitizerKind::MemTag);
+                     SanitizerKind::HWAddress | SanitizerKind::MemTag);
+}
+
+SanitizerMask expandKernelSanitizerMasks(SanitizerMask Mask) {
+  if (Mask & (SanitizerKind::Address | SanitizerKind::KernelAddress))
+    Mask |= SanitizerKind::Address | SanitizerKind::KernelAddress;
+  // Note: KHWASan doesn't support globals.
+  return Mask;
 }
 
 void SanitizerMetadata::reportGlobal(llvm::GlobalVariable *GV,
                                      SourceLocation Loc, StringRef Name,
-                                     QualType Ty, bool IsDynInit,
-                                     bool IsExcluded) {
-  IsDynInit &= !CGM.isInNoSanitizeList(GV, Loc, Ty, "init");
-  IsExcluded |= CGM.isInNoSanitizeList(GV, Loc, Ty);
+                                     QualType Ty,
+                                     SanitizerMask NoSanitizeAttrMask,
+                                     bool IsDynInit) {
+  SanitizerSet FsanitizeArgument = CGM.getLangOpts().Sanitize;
+  if (!isAsanHwasanOrMemTag(FsanitizeArgument))
+    return;
+
+  FsanitizeArgument.Mask = expandKernelSanitizerMasks(FsanitizeArgument.Mask);
+  NoSanitizeAttrMask = expandKernelSanitizerMasks(NoSanitizeAttrMask);
+  SanitizerSet NoSanitizeAttrSet = {NoSanitizeAttrMask &
+                                    FsanitizeArgument.Mask};
+
+  llvm::GlobalVariable::SanitizerMetadata Meta;
+  if (GV->hasSanitizerMetadata())
+    Meta = GV->getSanitizerMetadata();
+
+  Meta.NoAddress |= NoSanitizeAttrSet.hasOneOf(SanitizerKind::Address);
+  Meta.NoAddress |= CGM.isInNoSanitizeList(
+      FsanitizeArgument.Mask & SanitizerKind::Address, GV, Loc, Ty);
+
+  Meta.NoHWAddress |= NoSanitizeAttrSet.hasOneOf(SanitizerKind::HWAddress);
+  Meta.NoHWAddress |= CGM.isInNoSanitizeList(
+      FsanitizeArgument.Mask & SanitizerKind::HWAddress, GV, Loc, Ty);
+
+  Meta.NoMemtag |= NoSanitizeAttrSet.hasOneOf(SanitizerKind::MemTag);
+  Meta.NoMemtag |= CGM.isInNoSanitizeList(
+      FsanitizeArgument.Mask & SanitizerKind::MemTag, GV, Loc, Ty);
 
+  if (FsanitizeArgument.has(SanitizerKind::Address)) {
+    // TODO(hctim): Make this conditional when we migrate off llvm.asan.globals.
+    IsDynInit &= !CGM.isInNoSanitizeList(SanitizerKind::Address |
+                                             SanitizerKind::KernelAddress,
+                                         GV, Loc, Ty, "init");
+    Meta.IsDynInit = IsDynInit;
+  }
+
+  bool IsExcluded = Meta.NoAddress || Meta.NoHWAddress || Meta.NoMemtag;
+
+  GV->setSanitizerMetadata(Meta);
+
+  // TODO(hctim): Code below can be removed when we migrate off of
+  // llvm.asan.globals onto the new metadata attributes.
   llvm::Metadata *LocDescr = nullptr;
   llvm::Metadata *GlobalName = nullptr;
   llvm::LLVMContext &VMContext = CGM.getLLVMContext();
@@ -77,23 +124,13 @@ void SanitizerMetadata::reportGlobal(llvm::GlobalVariable *GV, const VarDecl &D,
 
     return NoSanitizeMask;
   };
-  reportGlobal(GV, D.getLocation(), OS.str(), D.getType(), IsDynInit,
-               SanitizerSet{getNoSanitizeMask(D)}.has(SanitizerKind::Address));
-}
 
-void SanitizerMetadata::reportGlobal(llvm::GlobalVariable *GV,
-                                     SourceLocation Loc, StringRef Name,
-                                     QualType Ty, bool IsDynInit) {
-  if (!isAsanHwasanOrMemTag(CGM.getLangOpts().Sanitize))
-    return;
-  reportGlobal(GV, Loc, Name, Ty, IsDynInit, false);
+  reportGlobal(GV, D.getLocation(), OS.str(), D.getType(), getNoSanitizeMask(D),
+               IsDynInit);
 }
 
 void SanitizerMetadata::disableSanitizerForGlobal(llvm::GlobalVariable *GV) {
-  // For now, just make sure the global is not modified by the ASan
-  // instrumentation.
-  if (isAsanHwasanOrMemTag(CGM.getLangOpts().Sanitize))
-    reportGlobal(GV, SourceLocation(), "", QualType(), false, true);
+  reportGlobal(GV, SourceLocation(), "", QualType(), SanitizerKind::All);
 }
 
 void SanitizerMetadata::disableSanitizerForInstruction(llvm::Instruction *I) {

clang/lib/CodeGen/SanitizerMetadata.h

@@ -14,6 +14,7 @@
 
 #include "clang/AST/Type.h"
 #include "clang/Basic/LLVM.h"
+#include "clang/Basic/Sanitizers.h"
 #include "clang/Basic/SourceLocation.h"
 
 namespace llvm {
@@ -40,7 +41,9 @@ class SanitizerMetadata {
   void reportGlobal(llvm::GlobalVariable *GV, const VarDecl &D,
                     bool IsDynInit = false);
   void reportGlobal(llvm::GlobalVariable *GV, SourceLocation Loc,
-                    StringRef Name, QualType Ty = {}, bool IsDynInit = false);
+                    StringRef Name, QualType Ty = {},
+                    SanitizerMask NoSanitizeAttrMask = {},
+                    bool IsDynInit = false);
   void disableSanitizerForGlobal(llvm::GlobalVariable *GV);
   void disableSanitizerForInstruction(llvm::Instruction *I);
 

clang/test/CodeGen/Inputs/sanitizer-special-case-list-globals.txt

@@ -0,0 +1,9 @@
+global:always_ignored
+[address]
+global:asan_ignored
+[hwaddress]
+global:hwasan_ignored
+[memtag]
+global:memtag_ignored
+[cfi-vcall|cfi-icall]
+src:*

clang/test/CodeGen/asan-globals.cpp

@@ -23,6 +23,9 @@ void func() {
   const char *literal = "Hello, world!";
 }
 
+// ASAN: @{{.*}}dyn_init_global{{.*}} ={{.*}} global {{.*}}, sanitize_address_dyninit
+// KASAN: @{{.*}}dyn_init_global{{.*}} ={{.*}} global {{.*}}, sanitize_address_dyninit
+
 // ASAN: sectioned_global{{.*}} global { i32, [28 x i8] }{{.*}}, align 32
 // KASAN: sectioned_global{{.*}} global i32
 // ASAN: @__special_global{{.*}} global { i32, [28 x i8] }{{.*}}, align 32

clang/test/CodeGen/sanitize-init-order.cpp

@@ -36,12 +36,29 @@ const volatile PODWithCtor array[5][5];
 
 // Check that ASan init-order checking ignores structs with trivial default
 // constructor.
+
+// CHECK: @s1 ={{.*}} global
+// CHECK-NOT: sanitize_address_dyninit
+// CHECK: @s2 ={{.*}} global
+// CHECK-NOT: sanitize_address_dyninit
+// CHECK: @s3 ={{.*}} global {{.*}}, sanitize_address_dyninit
+// CHECK: @{{.*}}array{{.*}} ={{.*}} global {{.*}}, sanitize_address_dyninit
+
 // CHECK: !llvm.asan.globals = !{![[GLOB_1:[0-9]+]], ![[GLOB_2:[0-9]+]], ![[GLOB_3:[0-9]+]], ![[GLOB_4:[0-9]+]]
 // CHECK: ![[GLOB_1]] = !{%struct.PODStruct* {{.*}}, i1 false, i1 false}
 // CHECK: ![[GLOB_2]] = !{%struct.PODWithDtor* {{.*}}, i1 false, i1 false}
 // CHECK: ![[GLOB_3]] = !{%struct.PODWithCtorAndDtor* {{.*}}, i1 true, i1 false}
 // CHECK: ![[GLOB_4]] = !{{{.*}}class.NS::PODWithCtor{{.*}}, i1 true, i1 false}
 
+// IGNORELIST: @s1 ={{.*}} global
+// IGNORELIST-NOT: sanitize_address_dyninit
+// IGNORELIST: @s2 ={{.*}} global
+// IGNORELIST-NOT: sanitize_address_dyninit
+// IGNORELIST: @s3 ={{.*}} global
+// IGNORELIST-NOT: sanitize_address_dyninit
+// IGNORELIST: @{{.*}}array{{.*}} ={{.*}} global
+// IGNORELIST-NOT: sanitize_address_dyninit
+
 // IGNORELIST: !llvm.asan.globals = !{![[GLOB_1:[0-9]+]], ![[GLOB_2:[0-9]+]], ![[GLOB_3:[0-9]+]], ![[GLOB_4:[0-9]+]]}
 // IGNORELIST: ![[GLOB_1]] = !{%struct.PODStruct* {{.*}}, i1 false, i1 false}
 // IGNORELIST: ![[GLOB_2]] = !{%struct.PODWithDtor* {{.*}}, i1 false, i1 false}

clang/test/CodeGen/sanitizer-special-case-list-globals.c

@@ -0,0 +1,91 @@
+/// Verify that ignorelist sections correctly select sanitizers to apply
+/// ignorelist entries to.
+
+// RUN: %clang_cc1 -emit-llvm %s -o -\
+// RUN: -fsanitize-ignorelist=%S/Inputs/sanitizer-special-case-list-globals.txt \
+// RUN: | FileCheck %s --check-prefix=NONE
+
+// RUN: %clang_cc1 -fsanitize=address -emit-llvm %s -o -\
+// RUN: -fsanitize-ignorelist=%S/Inputs/sanitizer-special-case-list-globals.txt \
+// RUN: | FileCheck %s --check-prefix=ASAN
+
+/// Note: HWASan effectively reorders globals (it puts the unsanitized ones
+/// first), which is hard to check for, as 'CHECK-DAG' doesn't play terribly
+/// nicely with 'CHECK-NOT'. This is why the 'always_ignored' and
+/// 'hwasan_ignored' comes first in this file.
+// RUN: %clang_cc1 -fsanitize=hwaddress -emit-llvm %s -o -\
+// RUN: -fsanitize-ignorelist=%S/Inputs/sanitizer-special-case-list-globals.txt \
+// RUN: | FileCheck %s --check-prefix=HWASAN
+
+/// TODO(hctim): Move over to memtag-globals when it's implemented. For now
+/// though, it's fine, the frontend still annotates based on any memtag sanitizer
+/// being used.
+// RUN: %clang_cc1 -fsanitize=memtag-heap -triple=aarch64-linux-android31 -emit-llvm %s -o -\
+// RUN: -fsanitize-ignorelist=%S/Inputs/sanitizer-special-case-list-globals.txt \
+// RUN: | FileCheck %s --check-prefix=MEMTAG
+
+/// Check that the '[cfi-vcall|cfi-icall] src:*' rule in the ignorelist doesn't change
+/// anything for ASan.
+// RUN: %clang_cc1 -fsanitize=address -emit-llvm %s -o -\
+// RUN: -fsanitize-ignorelist=%S/Inputs/sanitizer-special-case-list-globals.txt \
+// RUN: | FileCheck %s --check-prefix=ASAN
+
+/// Check that -fsanitize=kernel-address picks up the '[address]' groups.
+// RUN: %clang_cc1 -fsanitize=kernel-address -mllvm -hwasan-kernel=1 -emit-llvm %s -o -\
+// RUN: -fsanitize-ignorelist=%S/Inputs/sanitizer-special-case-list-globals.txt \
+// RUN: | FileCheck %s --check-prefix=ASAN
+
+/// KHWASan doesn't instrument global variables.
+// RUN: %clang_cc1 -fsanitize=kernel-hwaddress -mllvm -hwasan-kernel=1 -emit-llvm %s -o -\
+// RUN: -fsanitize-ignorelist=%S/Inputs/sanitizer-special-case-list-globals.txt \
+// RUN: | FileCheck %s --check-prefix=NONE
+
+/// Check that the '[cfi-vcall|cfi-icall] src:*' rule doesnt' emit anything for
+/// GVs.
+// RUN: %clang_cc1 -fsanitize=cfi-vcall,cfi-icall -emit-llvm %s -o -\
+// RUN: -fsanitize-ignorelist=%S/Inputs/sanitizer-special-case-list-globals.txt \
+// RUN: | FileCheck %s --check-prefix=NONE
+
+// NONE:     @always_ignored ={{.*}} global
+// NONE-NOT: no_sanitize
+// ASAN:     @always_ignored ={{.*}} global {{.*}}, no_sanitize_address
+// HWASAN:   @always_ignored ={{.*}} global {{.*}}, no_sanitize_hwaddress
+// MEMTAG:   @always_ignored ={{.*}} global {{.*}}, no_sanitize_memtag
+unsigned always_ignored;
+
+// NONE:       @hwasan_ignored ={{.*}} global
+// NONE-NOT:   no_sanitize
+// ASAN:       @hwasan_ignored ={{.*}} global
+// ASAN-NOT:   no_sanitize_address
+// HWASAN:     @hwasan_ignored ={{.*}} global {{.*}}, no_sanitize_hwaddress
+// MEMTAG:     @hwasan_ignored ={{.*}} global
+// MEMTAG-NOT: no_sanitize_memtag
+unsigned hwasan_ignored;
+
+// NONE:       @asan_ignored ={{.*}} global
+// NONE-NOT:   asan_ignored
+// ASAN:       @asan_ignored ={{.*}} global {{.*}}, no_sanitize_address
+// HWASAN:     @asan_ignored.hwasan = {{.*}} global
+// HWASAN-NOT: no_sanitize_hwaddress
+// MEMTAG:     @asan_ignored ={{.*}} global
+// MEMTAG-NOT: no_sanitize_memtag
+unsigned asan_ignored;
+
+// NONE:       @memtag_ignored ={{.*}} global
+// NONE-NOT:   memtag_ignored
+// ASAN:       @memtag_ignored ={{.*}} global
+// ASAN-NOT:   no_sanitize_address
+// HWASAN:     @memtag_ignored.hwasan = {{.*}} global
+// HWASAN-NOT: no_sanitize_hwaddress
+// MEMTAG:     @memtag_ignored ={{.*}} global {{.*}}, no_sanitize_memtag
+unsigned memtag_ignored;
+
+// NONE:       @never_ignored ={{.*}} global
+// NONE-NOT:   never_ignored
+// ASAN:       @never_ignored ={{.*}} global
+// ASAN-NOT:   no_sanitize_address
+// HWASAN:     @never_ignored.hwasan ={{.*}} global
+// HWASAN-NOT: no_sanitize_hwaddress
+// MEMTAG:     @never_ignored ={{.*}} global
+// MEMTAG-NOT: no_sanitize_memtag
+unsigned never_ignored;