Changeset 100633 in vbox for trunk/src/VBox/VMM/VMMAll

Timestamp:

Jul 18, 2023 2:05:10 PM (19 months ago)

Author:

vboxsync

svn:sync-xref-src-repo-rev:

158464

Message:

VMM/IEM: Check for too early IEMCPU::iEffSeg use during recompiler code generation. bugref:10369

Location:

trunk/src/VBox/VMM/VMMAll

Files:

• IEMAllInstructionsPython.py (modified) (1 diff)
• IEMAllThreadedPython.py (modified) (1 diff)

trunk/src/VBox/VMM/VMMAll/IEMAllInstructionsPython.py

@@ -2450 +2450 @@
             self.aoStmts = self.decodeCode(''.join(self.asLines));
         return self.aoStmts;
+
+
+    def checkForTooEarlyEffSegUse(self, aoStmts):
+        """
+        Checks if iEffSeg is used before the effective address has been decoded.
+        Returns None on success, error string on failure.
+
+        See r158454 for an example of this issue.
+        """
+
+        # Locate the IEM_MC_CALC_RM_EFF_ADDR statement, if found, scan backwards
+        # for IEMCPU::iEffSeg references. No need to check conditional branches,
+        # as we're ASSUMING these will not occur before address calculation.
+        for iStmt, oStmt in enumerate(aoStmts):
+            if oStmt.sName == 'IEM_MC_CALC_RM_EFF_ADDR':
+                while iStmt > 0:
+                    iStmt -= 1;
+                    oStmt  = aoStmts[iStmt];
+                    for sArg in oStmt.asParams:
+                        if sArg.find('pVCpu->iem.s.iEffSeg') >= 0:
+                            return "statement #%u: pVCpu->iem.s.iEffSeg is used prior to IEM_MC_CALC_RM_EFF_ADDR!" % (iStmt + 1,);
+                break;
+        return None;
+
+    def check(self):
+        """
+        Performs some sanity checks on the block.
+        Returns error string list, empty if all is fine.
+        """
+        aoStmts = self.decode();
+        asRet   = [];
+
+        sRet = self.checkForTooEarlyEffSegUse(aoStmts);
+        if sRet:
+            asRet.append(sRet);
+
+        return asRet;
+
 
 

trunk/src/VBox/VMM/VMMAll/IEMAllThreadedPython.py

@@ -952 +952 @@
         """
 
+        # Check the block for errors before we proceed (will decode it).
+        asErrors = self.oMcBlock.check();
+        if asErrors:
+            raise Exception('\n'.join(['%s:%s: error: %s' % (self.oMcBlock.sSrcFile, self.oMcBlock.iBeginLine, sError, )
+                                       for sError in asErrors]));
+
         # Decode the block into a list/tree of McStmt objects.
         aoStmts = self.oMcBlock.decode();