Custom registers read/written for the 'call' instruction

thesecretclub · Jul 6, 2024 · 1594c0d · 1594c0d
1 parent 461e8ce
commit 1594c0d
Showing 1 changed file with 9 additions and 0 deletions.
diff --git a/obfuscator/src/main.cpp b/obfuscator/src/main.cpp
@@ -276,6 +276,15 @@ struct Context
             data->flagsModified = flags.set0 | flags.set1 | flags.modified | flags.undefined;
             data->flagsTested   = flags.tested;
 
+            if (detail.getCategory() == x86::Category::Call)
+            {
+                // The call instruction clobbers all volatile registers
+                data->regsWritten = regMask(x86::rax) | regMask(x86::rcx) | regMask(x86::rdx)
+                                  | regMask(x86::r8) | regMask(x86::r9) | regMask(x86::r10) | regMask(x86::r11);
+                // The call instruction reads the first 4 arguments from rcx, rdx, r8, r9
+                data->regsRead = regMask(x86::rcx) | regMask(x86::rdx) | regMask(x86::r8) | regMask(x86::r9);
+            }
+
             node->setUserData(data);
         }
         return data;