[llvm] r213745 - [ARM] Make the assembler reject unpredictable pre/post-indexed ARM STR instructions.

[Tilmann Scheller]

Author: tilmann
Date: Wed Jul 23 07:38:17 2014
New Revision: 213745

URL: http://llvm.org/viewvc/llvm-project?rev=213745&view=rev
Log:
[ARM] Make the assembler reject unpredictable pre/post-indexed ARM STR instructions.

The ARM ARM prohibits STR instructions with writeback into the source register. With this commit this constraint is now enforced and we stop assembling STR instructions with unpredictable behavior.

Modified:
    llvm/trunk/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
    llvm/trunk/test/MC/ARM/diagnostics.s

Modified: llvm/trunk/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/AsmParser/ARMAsmParser.cpp?rev=213745&r1=213744&r2=213745&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/AsmParser/ARMAsmParser.cpp (original)
+++ llvm/trunk/lib/Target/ARM/AsmParser/ARMAsmParser.cpp Wed Jul 23 07:38:17 2014
@@ -5728,6 +5728,19 @@ bool ARMAsmParser::validateInstruction(M
                    "source operands must be sequential");
     return false;
   }
+  case ARM::STR_PRE_IMM:
+  case ARM::STR_PRE_REG:
+  case ARM::STR_POST_IMM:
+  case ARM::STR_POST_REG: {
+    // Rt must be different from Rn.
+    const unsigned Rt = MRI->getEncodingValue(Inst.getOperand(1).getReg());
+    const unsigned Rn = MRI->getEncodingValue(Inst.getOperand(2).getReg());
+
+    if (Rt == Rn)
+      return Error(Operands[3]->getStartLoc(),
+                   "source register and base register can't be identical");
+    return false;
+  }
   case ARM::SBFX:
   case ARM::UBFX: {
     // Width must be in range [1, 32-lsb].

Modified: llvm/trunk/test/MC/ARM/diagnostics.s
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/ARM/diagnostics.s?rev=213745&r1=213744&r2=213745&view=diff
==============================================================================
--- llvm/trunk/test/MC/ARM/diagnostics.s (original)
+++ llvm/trunk/test/MC/ARM/diagnostics.s Wed Jul 23 07:38:17 2014
@@ -491,3 +491,20 @@ foo2:
 @ CHECK-ERRORS:                 ^
 @ CHECK-ERRORS: error: immediate expression for mov requires :lower16: or :upper16
 @ CHECK-ERRORS:                  ^
+
+        str r0, [r0, #4]!
+        str r0, [r0, r1]!
+        str r0, [r0], #4
+        str r0, [r0], r1
+@ CHECK-ERRORS: error: source register and base register can't be identical
+@ CHECK-ERRORS: str r0, [r0, #4]!
+@ CHECK-ERRORS:         ^
+@ CHECK-ERRORS: error: source register and base register can't be identical
+@ CHECK-ERRORS: str r0, [r0, r1]!
+@ CHECK-ERRORS:         ^
+@ CHECK-ERRORS: error: source register and base register can't be identical
+@ CHECK-ERRORS: str r0, [r0], #4
+@ CHECK-ERRORS:         ^
+@ CHECK-ERRORS: error: source register and base register can't be identical
+@ CHECK-ERRORS: str r0, [r0], r1
+@ CHECK-ERRORS:         ^