[PATCH] D116048: [clang][CodeGen][UBSan] VLA size checking for unsigned integer parameter

[Adam Magier via Phabricator via cfe-commits]

AdamMagierFOSS added a comment.

Thank you for the feedback - I've added responses inline and I'll update the change to reflect the feedback.



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Comment at: clang/lib/CodeGen/CodeGenFunction.cpp:2247
       // Otherwise, evaluate and record it.
-      if (const Expr *size = vat->getSizeExpr()) {
+      if (const Expr *SizeExpr = vat->getSizeExpr()) {
         // It's possible that we might have emitted this already,
----------------
rjmccall wrote:
> Please continue to use lowercase names for local variables for consistency with the surrounding code.  The rename to `sizeExpr` is good; you can then rename `Size` to `size` or `sizeValue`.
Thank you for clarifying. I was unsure which style to stick to since I saw both "new style" code and "old style" code within the same scope, so I went with the "new style" to align with recent submissions to the clang project I looked at. It's no problem at all for me to switch my changes to the "old style" if that's preferred in this instance.


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Comment at: clang/lib/CodeGen/CodeGenFunction.cpp:2259
           //   greater than zero.
-          if (SanOpts.has(SanitizerKind::VLABound) &&
-              size->getType()->isSignedIntegerType()) {
+          if (SanOpts.has(SanitizerKind::VLABound) && SEType->isIntegerType()) {
             SanitizerScope SanScope(this);
----------------
rjmccall wrote:
> Sema requires the bound expression to have integral type, so you don't need to do this.
I suspected this would be unnecessary - thank you for confirming, I'll remove this.


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Comment at: clang/lib/CodeGen/CodeGenFunction.cpp:2275
           // undefined behavior to have a negative bound.
-          entry = Builder.CreateIntCast(Size, SizeTy, /*signed*/ false);
+          MapEntry = Builder.CreateIntCast(Size, SizeTy, /*signed*/ false);
         }
----------------
rjmccall wrote:
> This would be a different bug, but should UBSan also be doing a bounds check if the type is larger than `size_t`?
Interesting point, I'd have to reread through the spec to give a precise/definitive answer. To keep this review focused I'll table the discussion for a separate forum.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D116048/new/

https://reviews.llvm.org/D116048