[PATCH] D15642: [asan] Use private aliases for global variables (LLVM part).

[Maxim Ostapenko via llvm-commits]

m.ostapenko added inline comments.

================
Comment at: lib/Transforms/Instrumentation/AddressSanitizer.cpp:1399
@@ +1398,3 @@
+
+    if (ClUsePrivateAliasForGlobals) {
+      // Create local alias for NewGlobal to avoid crash on ODR between
----------------
ygribov wrote:
> Would it make sense to disable this on platforms that don't have aliases (Windows and maybe OSX)?
Yes, you are right, perhaps something like this:


```
    bool CanUsePrivateAliases = TargetTriple.isOSBinFormatELF();
    if (CanUsePrivateAliases && ClUsePrivateAliasForGlobals) {
      ...
```
?

================
Comment at: lib/Transforms/Instrumentation/AddressSanitizer.cpp:1408
@@ +1407,3 @@
+      // _odr_genXXX to detect ODR violation.
+      auto *ODRIndicatorSym =
+          new GlobalVariable(M, IRB.getInt8Ty(), false, Linkage,
----------------
ygribov wrote:
> Perhaps just reuse ODRIndicator here?
I use ODRIndicatorSym->copyAttributesFrom() that would be inaccessible if use ODRIndicator (that is Constant *). Perhaps we can change it's type to support copyAttributesFrom() interface, but I failed to find reasonable default value for it. If use Constant *, we can just use zero.


Repository:
  rL LLVM

http://reviews.llvm.org/D15642