[clang] [HLSL] enable Wconversion by default for HLSL (PR #166617)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-hlsl

Author: Sarah Spall (spall)

<details>
<summary>Changes</summary>

Add WConversion by default to cc1 args.  
Closes #<!-- -->134761 

---
Full diff: https://github.com/llvm/llvm-project/pull/166617.diff


3 Files Affected:

- (modified) clang/lib/Driver/ToolChains/HLSL.cpp (+4) 
- (modified) clang/lib/Driver/ToolChains/HLSL.h (+1) 
- (added) clang/test/Driver/HLSL/wconversion.hlsl (+7) 


``````````diff
diff --git a/clang/lib/Driver/ToolChains/HLSL.cpp b/clang/lib/Driver/ToolChains/HLSL.cpp
index 8d3fba7137c7c..5d7221b8718a9 100644
--- a/clang/lib/Driver/ToolChains/HLSL.cpp
+++ b/clang/lib/Driver/ToolChains/HLSL.cpp
@@ -567,3 +567,7 @@ bool HLSLToolChain::isLastJob(DerivedArgList &Args,
   // output to the result file.
   return true;
 }
+
+void HLSLToolChain::addClangWarningOptions(ArgStringList &CC1Args) const {
+  CC1Args.push_back("-Wconversion");
+}
diff --git a/clang/lib/Driver/ToolChains/HLSL.h b/clang/lib/Driver/ToolChains/HLSL.h
index 3aed904648429..7590659cf22a7 100644
--- a/clang/lib/Driver/ToolChains/HLSL.h
+++ b/clang/lib/Driver/ToolChains/HLSL.h
@@ -91,6 +91,7 @@ class LLVM_LIBRARY_VISIBILITY HLSLToolChain : public ToolChain {
   // Set default DWARF version to 4 for DXIL uses version 4.
   unsigned GetDefaultDwarfVersion() const override { return 4; }
 
+  void addClangWarningOptions(llvm::opt::ArgStringList &CC1Args) const override;
 private:
   mutable std::unique_ptr<tools::hlsl::Validator> Validator;
   mutable std::unique_ptr<tools::hlsl::MetalConverter> MetalConverter;
diff --git a/clang/test/Driver/HLSL/wconversion.hlsl b/clang/test/Driver/HLSL/wconversion.hlsl
new file mode 100644
index 0000000000000..1857a3dfe386e
--- /dev/null
+++ b/clang/test/Driver/HLSL/wconversion.hlsl
@@ -0,0 +1,7 @@
+// RUN: %clang_dxc -T lib_6_7 %s -### %s 2>&1 | FileCheck %s --check-prefixes=CONV
+// RUN: %clang_dxc -T lib_6_7 -Wno-conversion %s -### %s 2>&1 | FileCheck %s --check-prefixes=NOCONV
+
+// make sure we generate -Wconversion by default
+// CONV: "-Wconversion"
+// make sure -Wno-conversion still works
+// NOCONV: "-Wno-conversion"

``````````

</details>


https://github.com/llvm/llvm-project/pull/166617