[llvm] r225941 - X86: validate 'int' instruction

[Saleem Abdulrasool]

Author: compnerd
Date: Tue Jan 13 23:10:21 2015
New Revision: 225941

URL: http://llvm.org/viewvc/llvm-project?rev=225941&view=rev
Log:
X86: validate 'int' instruction

The int instruction takes as an operand an 8-bit immediate value.  Validate that
the input is valid rather than silently truncating the value.

Added:
    llvm/trunk/test/MC/X86/validate-inst-att.s
    llvm/trunk/test/MC/X86/validate-inst-intel.s
Modified:
    llvm/trunk/lib/Target/X86/AsmParser/X86AsmParser.cpp

Modified: llvm/trunk/lib/Target/X86/AsmParser/X86AsmParser.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/AsmParser/X86AsmParser.cpp?rev=225941&r1=225940&r2=225941&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/AsmParser/X86AsmParser.cpp (original)
+++ llvm/trunk/lib/Target/X86/AsmParser/X86AsmParser.cpp Tue Jan 13 23:10:21 2015
@@ -684,6 +684,7 @@ private:
   bool ParseDirectiveWord(unsigned Size, SMLoc L);
   bool ParseDirectiveCode(StringRef IDVal, SMLoc L);
 
+  bool validateInstruction(MCInst &Inst, const OperandVector &Ops);
   bool processInstruction(MCInst &Inst, const OperandVector &Ops);
 
   /// Wrapper around MCStreamer::EmitInstruction(). Possibly adds
@@ -2272,6 +2273,20 @@ static bool convert64i32to64ri8(MCInst &
   return convertToSExti8(Inst, Opcode, X86::RAX, isCmp);
 }
 
+bool X86AsmParser::validateInstruction(MCInst &Inst, const OperandVector &Ops) {
+  switch (Inst.getOpcode()) {
+  default: return true;
+  case X86::INT:
+    assert(Inst.getOperand(0).isImm() && "expected immediate");
+    if (Inst.getOperand(0).getImm() > 255) {
+      Error(Ops[1]->getStartLoc(), "interrupt vector must be in range [0-255]");
+      return false;
+    }
+    return true;
+  }
+  llvm_unreachable("handle the instruction appropriately");
+}
+
 bool X86AsmParser::processInstruction(MCInst &Inst, const OperandVector &Ops) {
   switch (Inst.getOpcode()) {
   default: return false;
@@ -2434,6 +2449,9 @@ bool X86AsmParser::MatchAndEmitATTInstru
                                isParsingIntelSyntax())) {
   default: llvm_unreachable("Unexpected match result!");
   case Match_Success:
+    if (!validateInstruction(Inst, Operands))
+      return true;
+
     // Some instructions need post-processing to, for example, tweak which
     // encoding is selected. Loop on it while changes happen so the
     // individual transformations can chain off each other.
@@ -2677,6 +2695,9 @@ bool X86AsmParser::MatchAndEmitIntelInst
   unsigned NumSuccessfulMatches =
       std::count(std::begin(Match), std::end(Match), Match_Success);
   if (NumSuccessfulMatches == 1) {
+    if (!validateInstruction(Inst, Operands))
+      return true;
+
     // Some instructions need post-processing to, for example, tweak which
     // encoding is selected. Loop on it while changes happen so the individual
     // transformations can chain off each other.

Added: llvm/trunk/test/MC/X86/validate-inst-att.s
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/X86/validate-inst-att.s?rev=225941&view=auto
==============================================================================
--- llvm/trunk/test/MC/X86/validate-inst-att.s (added)
+++ llvm/trunk/test/MC/X86/validate-inst-att.s Tue Jan 13 23:10:21 2015
@@ -0,0 +1,7 @@
+# RUN: not llvm-mc -triple i686 -filetype asm -o /dev/null %s 2>&1 | FileCheck %s
+
+	.text
+	int $65535
+# CHECK: error: interrupt vector must be in range [0-255]
+# CHECK:	int $65535
+# CHECK:            ^

Added: llvm/trunk/test/MC/X86/validate-inst-intel.s
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/X86/validate-inst-intel.s?rev=225941&view=auto
==============================================================================
--- llvm/trunk/test/MC/X86/validate-inst-intel.s (added)
+++ llvm/trunk/test/MC/X86/validate-inst-intel.s Tue Jan 13 23:10:21 2015
@@ -0,0 +1,9 @@
+# RUN: not llvm-mc -x86-asm-syntax intel -triple i686 -filetype asm -o /dev/null %s 2>&1 \
+# RUN:    | FileCheck %s
+
+	.text
+	int 65535
+# CHECK: error: interrupt vector must be in range [0-255]
+# CHECK:	int 65535
+# CHECK:            ^
+