[llvm] [llvm] Add format check for MCSubtargetFeatures (PR #180943)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-mc

Author: Georgiy Samoylov (sga-sc)

<details>
<summary>Changes</summary>

This patch adds some format check for MCSubtargetInfo class to prevent creation of inconsistent objects

This patch is also needed to fix lldb argument parsing (https://github.com/llvm/llvm-project/pull/180901)

---
Full diff: https://github.com/llvm/llvm-project/pull/180943.diff


1 Files Affected:

- (modified) llvm/include/llvm/MC/TargetRegistry.h (+27) 


``````````diff
diff --git a/llvm/include/llvm/MC/TargetRegistry.h b/llvm/include/llvm/MC/TargetRegistry.h
index 4451dfa72a5f4..7cbbffcdac11c 100644
--- a/llvm/include/llvm/MC/TargetRegistry.h
+++ b/llvm/include/llvm/MC/TargetRegistry.h
@@ -351,6 +351,31 @@ class Target {
   /// InstrumentManager, if registered (default = nullptr).
   InstrumentManagerCtorTy InstrumentManagerCtorFn = nullptr;
 
+  bool isValidFeatureListFormat(StringRef FeaturesString) const {
+    if (FeaturesString.empty())
+      return true;
+
+    llvm::SmallVector<llvm::StringRef, 8> Features;
+    FeaturesString.split(Features, ',', /*MaxSplit=*/-1, /*KeepEmpty=*/false);
+
+    if (Features.empty())
+      return false;
+
+    for (llvm::StringRef Feature : Features) {
+      if (Feature.empty())
+        return false;
+
+      char C = Feature.front();
+      if (C != '+' && C != '-')
+        return false;
+
+      if (Feature.size() == 1)
+        return false;
+    }
+
+    return true;
+  }
+
 public:
   Target() = default;
 
@@ -452,6 +477,8 @@ class Target {
                                          StringRef Features) const {
     if (!MCSubtargetInfoCtorFn)
       return nullptr;
+    if (!isValidFeatureListFormat(Features))
+      return nullptr;
     return MCSubtargetInfoCtorFn(TheTriple, CPU, Features);
   }
 

``````````

</details>


https://github.com/llvm/llvm-project/pull/180943