[SanitizerBounds] Add support for NoSanitizeBounds function

Currently adding attribute no_sanitize("bounds") isn't disabling
-fsanitize=local-bounds (also enabled in -fsanitize=bounds). The Clang
frontend handles fsanitize=array-bounds which can already be disabled by
no_sanitize("bounds"). However, instrumentation added by the
BoundsChecking pass in the middle-end cannot be disabled by the
attribute.

The fix is very similar to D102772 that added the ability to selectively
disable sanitizer pass on certain functions.

In this patch, if no_sanitize("bounds") is provided, an additional
function attribute (NoSanitizeBounds) is attached to IR to let the
BoundsChecking pass know we want to disable local-bounds checking. In
order to support this feature, the IR is extended (similar to D102772)
to make Clang able to preserve the information and let BoundsChecking
pass know bounds checking is disabled for certain function.

Reviewed By: melver

Differential Revision: https://reviews.llvm.org/D119816

1 files changed, 4 insertions, 0 deletions

diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index 9c3e5d5..c1f3a30 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -740,6 +740,7 @@ void CodeGenFunction::StartFunction(GlobalDecl GD, QualType RetTy,
   } while (false);
 
   if (D) {
+    const bool SanitizeBounds = SanOpts.hasOneOf(SanitizerKind::Bounds);
     bool NoSanitizeCoverage = false;
 
     for (auto Attr : D->specific_attrs<NoSanitizeAttr>()) {
@@ -760,6 +761,9 @@ void CodeGenFunction::StartFunction(GlobalDecl GD, QualType RetTy,
         NoSanitizeCoverage = true;
     }
 
+    if (SanitizeBounds && !SanOpts.hasOneOf(SanitizerKind::Bounds))
+      Fn->addFnAttr(llvm::Attribute::NoSanitizeBounds);
+
     if (NoSanitizeCoverage && CGM.getCodeGenOpts().hasSanitizeCoverage())
       Fn->addFnAttr(llvm::Attribute::NoSanitizeCoverage);
   }