[mips] Correct .MIPS.abiflags for -mfpxx on MIPS32r6

[dsanders]

Summary

The cpr1_size field describes the minimum register width to run the program
rather than the size of the registers on the target. MIPS32r6 was acting
as if -mfp64 has been given because it starts off with 64-bit FPU registers.

[sstankovic]

LGTM

lib/Target/Mips/MCTargetDesc/MipsABIFlagsSection.h

MipsABIFlagsSection()
       : Version(0), ISALevel(0), ISARevision(0), GPRSize(AFL_REG_NONE),
         CPR1Size(AFL_REG_NONE), CPR2Size(AFL_REG_NONE), ISAExtensionSet(0),
         ASESet(0), OddSPReg(false), Is32BitABI(false), FpABI(FpABIKind::ANY) {}
 
   uint16_t getVersionValue() { return (uint16_t)Version; }
   uint8_t getISALevelValue() { return (uint8_t)ISALevel; }
   uint8_t getISARevisionValue() { return (uint8_t)ISARevision; }
   uint8_t getGPRSizeValue() { return (uint8_t)GPRSize; }
-  uint8_t getCPR1SizeValue() { return (uint8_t)CPR1Size; }
+  uint8_t getCPR1SizeValue();
   uint8_t getCPR2SizeValue() { return (uint8_t)CPR2Size; }
   uint8_t getFpABIValue();
   uint32_t getISAExtensionSetValue() { return (uint32_t)ISAExtensionSet; }
   uint32_t getASESetValue() { return (uint32_t)ASESet; }
 
   uint32_t getFlags1Value() {
     uint32_t Value = 0;
 
public:
   template <class PredicateLibrary>
   void setFpAbiFromPredicates(const PredicateLibrary &P) {
     Is32BitABI = P.isABI_O32();
 
     FpABI = FpABIKind::ANY;
     if (P.isABI_N32() || P.isABI_N64())
       FpABI = FpABIKind::S64;
     else if (P.isABI_O32()) {
-      if (P.isFP64bit())
-        FpABI = FpABIKind::S64;
-      else if (P.isABI_FPXX())
+      if (P.isABI_FPXX())
         FpABI = FpABIKind::XX;
+      else if (P.isFP64bit())
+        FpABI = FpABIKind::S64;
       else
         FpABI = FpABIKind::S32;
     }
   }
 
   template <class PredicateLibrary>
   void setAllFromPredicates(const PredicateLibrary &P) {
     setISALevelAndRevisionFromPredicates(P);

lib/Target/Mips/MCTargetDesc/MipsABIFlagsSection.cpp

case FpABIKind::S32:
     return "32";
   case FpABIKind::S64:
     return "64";
   default:
     llvm_unreachable("unsupported fp abi value");
   }
 }
 
+uint8_t MipsABIFlagsSection::getCPR1SizeValue() {
+  if (FpABI == FpABIKind::XX)
+    return (uint8_t)AFL_REG_32;
+  return (uint8_t)CPR1Size;
+}
+
 namespace llvm {
 MCStreamer &operator<<(MCStreamer &OS, MipsABIFlagsSection &ABIFlagsSection) {
   // Write out a Elf_Internal_ABIFlags_v0 struct
   OS.EmitIntValue(ABIFlagsSection.getVersionValue(), 2);         // version
   OS.EmitIntValue(ABIFlagsSection.getISALevelValue(), 1);        // isa_level
   OS.EmitIntValue(ABIFlagsSection.getISARevisionValue(), 1);     // isa_rev
   OS.EmitIntValue(ABIFlagsSection.getGPRSizeValue(), 1);         // gpr_size
   OS.EmitIntValue(ABIFlagsSection.getCPR1SizeValue(), 1);        // cpr1_size

test/MC/Mips/mips_abi_flags_xx.s

 # RUN: llvm-mc %s -arch=mips -mcpu=mips32 | \
 # RUN:   FileCheck %s -check-prefix=CHECK-ASM
 #
 # RUN: llvm-mc %s -arch=mips -mcpu=mips32 -filetype=obj -o - | \
 # RUN:   llvm-readobj -sections -section-data -section-relocations - | \
-# RUN:     FileCheck %s -check-prefix=CHECK-OBJ
+# RUN:     FileCheck %s -check-prefix=CHECK-OBJ -check-prefix=CHECK-OBJ-R1
 
 # RUN: llvm-mc /dev/null -arch=mips -mcpu=mips32 -mattr=fpxx -filetype=obj -o - | \
 # RUN:   llvm-readobj -sections -section-data -section-relocations - | \
-# RUN:     FileCheck %s -check-prefix=CHECK-OBJ
+# RUN:     FileCheck %s -check-prefix=CHECK-OBJ -check-prefix=CHECK-OBJ-R1
+
+# RUN: llvm-mc /dev/null -arch=mips -mcpu=mips32r6 -mattr=fpxx -filetype=obj -o - | \
+# RUN:   llvm-readobj -sections -section-data -section-relocations - | \
+# RUN:     FileCheck %s -check-prefix=CHECK-OBJ -check-prefix=CHECK-OBJ-R6
 
 # CHECK-ASM: .module fp=xx
 
 # Checking if the Mips.abiflags were correctly emitted.
 # CHECK-OBJ:       Section {
 # CHECK-OBJ:         Index: 5
 # CHECK-OBJ-LABEL:   Name: .MIPS.abiflags (12)
 # CHECK-OBJ:         Type: SHT_MIPS_ABIFLAGS (0x7000002A)
 # CHECK-OBJ:          Flags [ (0x2)
 # CHECK-OBJ:           SHF_ALLOC (0x2)
 # CHECK-OBJ:         ]
 # CHECK-OBJ:         Address: 0x0
 # CHECK-OBJ:         Size: 24
 # CHECK-OBJ:         Link: 0
 # CHECK-OBJ:         Info: 0
 # CHECK-OBJ:         AddressAlignment: 8
 # CHECK-OBJ:         EntrySize: 24
 # CHECK-OBJ:         Relocations [
 # CHECK-OBJ:         ]
 # CHECK-OBJ:         SectionData (
-# CHECK-OBJ:           0000: 00002001 01010005 00000000 00000000  |.. .............|
+# CHECK-OBJ-R1:        0000: 00002001 01010005 00000000 00000000  |.. .............|
+# CHECK-OBJ-R6:        0000: 00002006 01010005 00000000 00000000  |.. .............|
 # CHECK-OBJ:           0010: 00000001 00000000                    |........|
 # CHECK-OBJ:         )
 # CHECK-OBJ-LABEL: }
 
         .module fp=xx
 
 # FIXME: Test should include gnu_attributes directive when implemented.
 #        An explicit .gnu_attribute must be checked against the effective
 #        command line options and any inconsistencies reported via a warning.