- thumbv6 shouldn't imply +thumb2. Cortex-M0 doesn't suppport 32-bit Thumb2

  instructions.
- However, it does support dmb, dsb, isb, mrs, and msr.
rdar://11331541

llvm-svn: 155685

2 files changed, 28 insertions, 16 deletions

diff --git a/llvm/lib/Target/ARM/ARMInstrThumb2.td b/llvm/lib/Target/ARM/ARMInstrThumb2.td
index bbb7c805722..a166b27042d 100644
--- a/llvm/lib/Target/ARM/ARMInstrThumb2.td
+++ b/llvm/lib/Target/ARM/ARMInstrThumb2.td
@@ -3017,7 +3017,7 @@ def t2DSB : AInoP<(outs), (ins memb_opt:$opt), ThumbFrm, NoItinerary,
 
 def t2ISB : AInoP<(outs), (ins memb_opt:$opt), ThumbFrm, NoItinerary,
                   "isb", "\t$opt",
-                  []>, Requires<[IsThumb2, HasDB]> {
+                  []>, Requires<[IsThumb, HasDB]> {
   bits<4> opt;
   let Inst{31-4} = 0xf3bf8f6;
   let Inst{3-0} = opt;
@@ -3646,7 +3646,7 @@ def t2MRSsys_AR: T2I<(outs GPR:$Rd), (ins), NoItinerary, "mrs", "\t$Rd, spsr",
 // the A/R class (a full msr_mask).
 def t2MRS_M : T2I<(outs rGPR:$Rd), (ins msr_mask:$mask), NoItinerary,
                   "mrs", "\t$Rd, $mask", []>,
-              Requires<[IsThumb2,IsMClass]> {
+              Requires<[IsThumb,IsMClass]> {
   bits<4> Rd;
   bits<8> mask;
   let Inst{31-12} = 0b11110011111011111000;
@@ -3682,7 +3682,7 @@ def t2MSR_AR : T2I<(outs), (ins msr_mask:$mask, rGPR:$Rn),
 // Move from ARM core register to Special Register
 def t2MSR_M : T2I<(outs), (ins msr_mask:$SYSm, rGPR:$Rn),
                   NoItinerary, "msr", "\t$SYSm, $Rn", []>,
-              Requires<[IsThumb2,IsMClass]> {
+              Requires<[IsThumb,IsMClass]> {
   bits<8> SYSm;
   bits<4> Rn;
   let Inst{31-21} = 0b11110011100;
@@ -4002,9 +4002,9 @@ def : t2InstAlias<"tst${p} $Rn, $Rm",
                   (t2TSTrr GPRnopc:$Rn, rGPR:$Rm, pred:$p)>;
 
 // Memory barriers
-def : InstAlias<"dmb", (t2DMB 0xf)>, Requires<[IsThumb2, HasDB]>;
-def : InstAlias<"dsb", (t2DSB 0xf)>, Requires<[IsThumb2, HasDB]>;
-def : InstAlias<"isb", (t2ISB 0xf)>, Requires<[IsThumb2, HasDB]>;
+def : InstAlias<"dmb", (t2DMB 0xf)>, Requires<[IsThumb, HasDB]>;
+def : InstAlias<"dsb", (t2DSB 0xf)>, Requires<[IsThumb, HasDB]>;
+def : InstAlias<"isb", (t2ISB 0xf)>, Requires<[IsThumb, HasDB]>;
 
 // Alias for LDR, LDRB, LDRH, LDRSB, and LDRSH without the ".w" optional
 // width specifier.
diff --git a/llvm/lib/Target/ARM/MCTargetDesc/ARMMCTargetDesc.cpp b/llvm/lib/Target/ARM/MCTargetDesc/ARMMCTargetDesc.cpp
index 67f6f6f3520..5df84c8b103 100644
--- a/llvm/lib/Target/ARM/MCTargetDesc/ARMMCTargetDesc.cpp
+++ b/llvm/lib/Target/ARM/MCTargetDesc/ARMMCTargetDesc.cpp
@@ -51,23 +51,32 @@ std::string ARM_MC::ParseARMTriple(StringRef TT, StringRef CPU) {
       Idx = 6;
   }
 
+  bool NoCPU = CPU == "generic" || CPU.empty();
   std::string ARMArchFeature;
   if (Idx) {
     unsigned SubVer = TT[Idx];
     if (SubVer >= '7' && SubVer <= '9') {
       if (Len >= Idx+2 && TT[Idx+1] == 'm') {
-        // v7m: FeatureNoARM, FeatureDB, FeatureHWDiv, FeatureMClass
-        ARMArchFeature = "+v7,+noarm,+db,+hwdiv,+mclass";
+        if (NoCPU)
+          // v7m: FeatureNoARM, FeatureDB, FeatureHWDiv, FeatureMClass
+          ARMArchFeature = "+v7,+noarm,+db,+hwdiv,+mclass";
+        else
+          // Use CPU to figure out the exact features.
+          ARMArchFeature = "+v7";
       } else if (Len >= Idx+3 && TT[Idx+1] == 'e'&& TT[Idx+2] == 'm') {
-        // v7em: FeatureNoARM, FeatureDB, FeatureHWDiv, FeatureDSPThumb2,
-        //       FeatureT2XtPk, FeatureMClass
-        ARMArchFeature = "+v7,+noarm,+db,+hwdiv,+t2dsp,t2xtpk,+mclass";
+        if (NoCPU)
+          // v7em: FeatureNoARM, FeatureDB, FeatureHWDiv, FeatureDSPThumb2,
+          //       FeatureT2XtPk, FeatureMClass
+          ARMArchFeature = "+v7,+noarm,+db,+hwdiv,+t2dsp,t2xtpk,+mclass";
+        else
+          // Use CPU to figure out the exact features.
+          ARMArchFeature = "+v7";
       } else {
         // v7 CPUs have lots of different feature sets. If no CPU is specified,
         // then assume v7a (e.g. cortex-a8) feature set. Otherwise, return
         // the "minimum" feature set and use CPU string to figure out the exact
         // features.
-        if (CPU == "generic")
+        if (NoCPU)
           // v7a: FeatureNEON, FeatureDB, FeatureDSPThumb2, FeatureT2XtPk
           ARMArchFeature = "+v7,+neon,+db,+t2dsp,+t2xtpk";
         else
@@ -77,10 +86,13 @@ std::string ARM_MC::ParseARMTriple(StringRef TT, StringRef CPU) {
     } else if (SubVer == '6') {
       if (Len >= Idx+3 && TT[Idx+1] == 't' && TT[Idx+2] == '2')
         ARMArchFeature = "+v6t2";
-      else if (Len >= Idx+2 && TT[Idx+1] == 'm')
-        // v6m: FeatureNoARM, FeatureMClass
-        ARMArchFeature = "+v6t2,+noarm,+mclass";
-      else
+      else if (Len >= Idx+2 && TT[Idx+1] == 'm') {
+        if (NoCPU)
+          // v6m: FeatureNoARM, FeatureMClass
+          ARMArchFeature = "+v6,+noarm,+mclass";
+        else
+          ARMArchFeature = "+v6";
+      } else
         ARMArchFeature = "+v6";
     } else if (SubVer == '5') {
       if (Len >= Idx+3 && TT[Idx+1] == 't' && TT[Idx+2] == 'e')