[ARM] Warn on deprecated IT blocks in v8 AArch32 assembly.

Patch by Artyom Skrobov.

llvm-svn: 191885

1 files changed, 17 insertions, 6 deletions

diff --git a/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp b/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
index ebc382cef44..71f98abe1d4 100644
--- a/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
+++ b/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
@@ -7,6 +7,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "ARMFeatures.h"
 #include "llvm/MC/MCTargetAsmParser.h"
 #include "MCTargetDesc/ARMAddressingModes.h"
 #include "MCTargetDesc/ARMBaseInfo.h"
@@ -7622,12 +7623,22 @@ MatchAndEmitInstruction(SMLoc IDLoc, unsigned &Opcode,
       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. E.g.,
-    // tPOP(r8)->t2LDMIA_UPD(sp,r8)->t2STR_POST(sp,r8)
-    while (processInstruction(Inst, Operands))
-      ;
+    { // processInstruction() updates inITBlock state, we need to save it away
+      bool wasInITBlock = inITBlock();
+
+      // 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. E.g.,
+      // tPOP(r8)->t2LDMIA_UPD(sp,r8)->t2STR_POST(sp,r8)
+      while (processInstruction(Inst, Operands))
+        ;
+
+      // Only after the instruction is fully processed, we can validate it
+      if (wasInITBlock && hasV8Ops() && isThumb() &&
+          !isV8EligibleForIT(&Inst, 2)) {
+        Warning(IDLoc, "deprecated instruction in IT block");
+      }
+    }
 
     // Only move forward at the very end so that everything in validate
     // and process gets a consistent answer about whether we're in an IT