[UBSan] Strengthen pointer checks in 'new' expressions

With this change compiler generates alignment checks for wider range
of types. Previously such checks were generated only for the record types
with non-trivial default constructor. So the types like:

    struct alignas(32) S2 { int x; };
    typedef __attribute__((ext_vector_type(2), aligned(32))) float float32x2_t;

did not get checks when allocated by 'new' expression.

This change also optimizes the checks generated for the arrays created
in 'new' expressions. Previously the check was generated for each
invocation of type constructor. Now the check is generated only once
for entire array.

Differential Revision: https://reviews.llvm.org/D49589

llvm-svn: 338199

1 files changed, 18 insertions, 3 deletions

diff --git a/clang/lib/CodeGen/CGValue.h b/clang/lib/CodeGen/CGValue.h
index 418bda1f41b..60f205932b5 100644
--- a/clang/lib/CodeGen/CGValue.h
+++ b/clang/lib/CodeGen/CGValue.h
@@ -479,12 +479,20 @@ class AggValueSlot {
   /// the size of the type.
   bool OverlapFlag : 1;
 
+  /// If is set to true, sanitizer checks are already generated for this address
+  /// or not required. For instance, if this address represents an object
+  /// created in 'new' expression, sanitizer checks for memory is made as a part
+  /// of 'operator new' emission and object constructor should not generate
+  /// them.
+  bool SanitizerCheckedFlag : 1;
+
 public:
   enum IsAliased_t { IsNotAliased, IsAliased };
   enum IsDestructed_t { IsNotDestructed, IsDestructed };
   enum IsZeroed_t { IsNotZeroed, IsZeroed };
   enum Overlap_t { DoesNotOverlap, MayOverlap };
   enum NeedsGCBarriers_t { DoesNotNeedGCBarriers, NeedsGCBarriers };
+  enum IsSanitizerChecked_t { IsNotSanitizerChecked, IsSanitizerChecked };
 
   /// ignored - Returns an aggregate value slot indicating that the
   /// aggregate value is being ignored.
@@ -509,7 +517,8 @@ public:
                               NeedsGCBarriers_t needsGC,
                               IsAliased_t isAliased,
                               Overlap_t mayOverlap,
-                              IsZeroed_t isZeroed = IsNotZeroed) {
+                              IsZeroed_t isZeroed = IsNotZeroed,
+                       IsSanitizerChecked_t isChecked = IsNotSanitizerChecked) {
     AggValueSlot AV;
     if (addr.isValid()) {
       AV.Addr = addr.getPointer();
@@ -524,6 +533,7 @@ public:
     AV.ZeroedFlag = isZeroed;
     AV.AliasedFlag = isAliased;
     AV.OverlapFlag = mayOverlap;
+    AV.SanitizerCheckedFlag = isChecked;
     return AV;
   }
 
@@ -532,9 +542,10 @@ public:
                                 NeedsGCBarriers_t needsGC,
                                 IsAliased_t isAliased,
                                 Overlap_t mayOverlap,
-                                IsZeroed_t isZeroed = IsNotZeroed) {
+                                IsZeroed_t isZeroed = IsNotZeroed,
+                       IsSanitizerChecked_t isChecked = IsNotSanitizerChecked) {
     return forAddr(LV.getAddress(), LV.getQuals(), isDestructed, needsGC,
-                   isAliased, mayOverlap, isZeroed);
+                   isAliased, mayOverlap, isZeroed, isChecked);
   }
 
   IsDestructed_t isExternallyDestructed() const {
@@ -586,6 +597,10 @@ public:
     return Overlap_t(OverlapFlag);
   }
 
+  bool isSanitizerChecked() const {
+    return SanitizerCheckedFlag;
+  }
+
   RValue asRValue() const {
     if (isIgnored()) {
       return RValue::getIgnored();