Merge pull request #9454 from cocoa55/fix/rewriter-branch-into-cut

fix(codegen): reject branches into a rewritten instruction

core/relinker/codegen/src/x86/X64InstructionRewriter.cpp

@@ -54,6 +54,12 @@ std::int64_t X64InstructionRewriter::AdjustedDelta(
     std::int64_t sliceSize,
     std::int64_t delta
 ) {
+    const bool targetInsideCut = targetPosition > cutStart && targetPosition < cutEnd;
+
+    if (targetInsideCut) {
+        throw CodegenException("Branch target inside rewritten instruction", static_cast<Domain::FileByteOffset>(instrPosition));
+    }
+
     const bool instrShifts = instrPosition >= cutEnd && instrPosition < sliceSize;
     const bool targetShifts = targetPosition >= cutEnd && targetPosition < sliceSize;
 

core/relinker/codegen/tests/RewriteBoundaryTests.cpp

@@ -54,6 +54,16 @@ int main() {
         Require(result.Bytes == std::vector<std::uint8_t>{
             0x90, 0x90, 0x90, 0xC3});
 
+        bool targetInsideCutRejected = false;
+        try {
+            (void)rewriter.Rewrite(
+                {0xEB, 0x01, 0xB8, 0x11, 0x22, 0x33, 0x44, 0xC3},
+                {2, {0x90}});
+        } catch (const std::exception&) {
+            targetInsideCutRejected = true;
+        }
+        Require(targetInsideCutRejected);
+
         for (const auto& code : {
                  std::vector<std::uint8_t>{
                      0x66, 0xEB, 0x01, 0x90, 0xC3},
@@ -107,7 +117,7 @@ int main() {
         }
         RequireTruncatedBranchRejected(backwardWraparoundRejected);
 
-        std::cout << "21 rewrite boundary cases passed\n";
+        std::cout << "22 rewrite boundary cases passed\n";
     } catch (const std::exception& error) {
         std::cerr << error.what() << '\n';
         return 1;