Add flags for overflow on clang.

[AaronRobinsonMSFT]

In clang-20 there is a known breaking change to -fwrapv that impacted us. Details can be found at https://releases.llvm.org/20.1.0/tools/clang/docs/ReleaseNotes.html#potentially-breaking-changes.

Add the -fno-strict-aliasing to match our MSVC usage as well.

Contributes to #119706

[AaronRobinsonMSFT]

/cc @rnkovacs

[dotnet-policy-service]

Tagging subscribers to this area: @mangod9
See info in area-owners.md if you want to be subscribed.

[jkotas]

LGTM. Thank you!

[jkoritzinsky]

One of these days I'll get UBSAN working..

[jkotas]

We should have a build image with clang 21 now: dotnet/dotnet-buildtools-prereqs-docker#1516

You can try updating all mcr.microsoft.com/dotnet-buildtools/prereqs:azurelinux-3.0-net10.0 under eng to mcr.microsoft.com/dotnet-buildtools/prereqs:azurelinux-3.0-net11.0 in this PR to check what the CI tests think about it.

[am11]

Last CI run still used clang 20:

  -- The C compiler identification is Clang 20.1.8
  -- The CXX compiler identification is Clang 20.1.8

New images were built a few hours ago dotnet/dotnet-buildtools-prereqs-docker#1516 (comment) (it doesn't automatically rebuild the subtree).

[am11]

@jkotas, looks like we need to apply:

--- a/src/native/libs/System.Security.Cryptography.Native/pal_x509.c
+++ b/src/native/libs/System.Security.Cryptography.Native/pal_x509.c
@@ -1250,6 +1250,7 @@ static int32_t X509ChainVerifyOcsp(X509_STORE_CTX* storeCtx, X509* subject, X509
             {
 #pragma clang diagnostic push
 #pragma clang diagnostic ignored "-Wcast-qual"
+#pragma clang diagnostic ignored "-Wimplicit-void-ptr-cast"
                 if (i2d_OCSP_RESPONSE_bio(bio, resp))
 #pragma clang diagnostic pop
                 {

[am11]

FreeBSD build fix:

--- a/src/native/libs/System.Native/pal_interfaceaddresses.c
+++ b/src/native/libs/System.Native/pal_interfaceaddresses.c
@@ -561,7 +561,7 @@ int32_t SystemNative_EnumerateGatewayAddressesForInterface(void* context, uint32
         return -1;
     }
 
-    uint8_t* buffer = malloc(byteCount);
+    uint8_t* buffer = (uint8_t*)malloc(byteCount);
     if (buffer == NULL)
     {
         errno = ENOMEM;
@@ -587,7 +587,7 @@ int32_t SystemNative_EnumerateGatewayAddressesForInterface(void* context, uint32
 
         byteCount = tmpEstimatedSize;
         free(buffer);
-        buffer = malloc(byteCount);
+        buffer = (uint8_t*)malloc(byteCount);
         if (buffer == NULL)
         {
             errno = ENOMEM;

[am11]

It would be nice to update tables in https://github.com/dotnet/runtime/blob/f0db8f9d9668ba03897739152d02623acbd04466/docs/workflow/using-docker.md at the same time (replace net10 with net11). It can be done in a follow-up PR. :)

[jkotas]

/azp run runtime-coreclr outerloop

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[AaronRobinsonMSFT]

/azp run runtime-coreclr outerloop

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[AaronRobinsonMSFT]

/azp run runtime-coreclr outerloop

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[AaronRobinsonMSFT]

/ba-g Unrelated failures in outerloop

[tmds]

@AaronRobinsonMSFT perhaps this is needed in some other places too: https://github.com/search?q=repo%3Adotnet%2Fdotnet%20-fwrapv&type=code

[am11]

Automated code flow will sync with VMR.

[tmds]

@am11 did you click the link? There's some thing for mono, and also in src/deployment-tools and src/diagnostics.

[am11]

We sync eng/native with dotnet/diagnostics from time to time. I can resync it. Not sure if deployment-tools uses these configs.