[ARM] Fix FP ABI attributes with no VFP

[aemerson]

Summary

Undo part of a change in r192111 which erroneously omitted the Tag_ABI_FP_* attributes when vfp was not present.

Previous behaviour is restored and tests are updated to reflect this.

[richard.barton.arm]

LGTM. Closer reading of the ABI addendum shows that these are PCS attributes and describe compatibility with the ABI rather than the available target features - apologies for missing it in the last review.

lib/Target/ARM/ARMAsmPrinter.cpp

       AttrEmitter->EmitAttribute(ARMBuildAttrs::Advanced_SIMD_arch,
                                  ARMBuildAttrs::AllowedNeonV8);
     else
       AttrEmitter->EmitAttribute(ARMBuildAttrs::Advanced_SIMD_arch,
                                  ARMBuildAttrs::Allowed);
   }
 
   // Signal various FP modes.
-  if (Subtarget->hasVFP2()) {
-    if (!TM.Options.UnsafeFPMath) {
-      AttrEmitter->EmitAttribute(ARMBuildAttrs::ABI_FP_denormal,
-                                 ARMBuildAttrs::Allowed);
-      AttrEmitter->EmitAttribute(ARMBuildAttrs::ABI_FP_exceptions,
-                                 ARMBuildAttrs::Allowed);
-    }
-
-    if (TM.Options.NoInfsFPMath && TM.Options.NoNaNsFPMath)
-      AttrEmitter->EmitAttribute(ARMBuildAttrs::ABI_FP_number_model,
-                                 ARMBuildAttrs::Allowed);
-    else
-      AttrEmitter->EmitAttribute(ARMBuildAttrs::ABI_FP_number_model,
-                                 ARMBuildAttrs::AllowIEE754);
+  if (!TM.Options.UnsafeFPMath) {
+    AttrEmitter->EmitAttribute(ARMBuildAttrs::ABI_FP_denormal,
+                               ARMBuildAttrs::Allowed);
+    AttrEmitter->EmitAttribute(ARMBuildAttrs::ABI_FP_exceptions,
+                               ARMBuildAttrs::Allowed);
   }
 
+  if (TM.Options.NoInfsFPMath && TM.Options.NoNaNsFPMath)
+    AttrEmitter->EmitAttribute(ARMBuildAttrs::ABI_FP_number_model,
+                               ARMBuildAttrs::Allowed);
+  else
+    AttrEmitter->EmitAttribute(ARMBuildAttrs::ABI_FP_number_model,
+                               ARMBuildAttrs::AllowIEE754);
+
   // FIXME: add more flags to ARMBuildAttrs.h
   // 8-bytes alignment stuff.
   AttrEmitter->EmitAttribute(ARMBuildAttrs::ABI_align8_needed, 1);
   AttrEmitter->EmitAttribute(ARMBuildAttrs::ABI_align8_preserved, 1);
 
   // Hard float.  Use both S and D registers and conform to AAPCS-VFP.
   if (Subtarget->isAAPCS_ABI() && TM.Options.FloatABIType == FloatABI::Hard) {
     AttrEmitter->EmitAttribute(ARMBuildAttrs::ABI_HardFP_use, 3);

test/CodeGen/ARM/2010-09-29-mc-asm-header-test.ll

 ; RUN: llc < %s -mtriple=armv6-linux-gnueabi | FileCheck %s --check-prefix=V6
 ; RUN: llc < %s -mtriple=thumbv6m-linux-gnueabi | FileCheck %s --check-prefix=V6M
 ; RUN: llc < %s -mtriple=armv6-linux-gnueabi -mcpu=arm1156t2f-s | FileCheck %s --check-prefix=ARM1156T2F-S
 ; RUN: llc < %s -mtriple=thumbv7m-linux-gnueabi | FileCheck %s --check-prefix=V7M
 ; RUN: llc < %s -mtriple=armv7-linux-gnueabi | FileCheck %s --check-prefix=V7
 ; RUN: llc < %s -mtriple=armv8-linux-gnueabi | FileCheck %s --check-prefix=V8
 ; RUN: llc < %s -mtriple=thumbv8-linux-gnueabi | FileCheck %s --check-prefix=Vt8
 ; RUN: llc < %s -mtriple=armv8-linux-gnueabi -mattr=+fp-armv8 | FileCheck %s --check-prefix=V8-FPARMv8
 ; RUN: llc < %s -mtriple=armv8-linux-gnueabi -mattr=+neon | FileCheck %s --check-prefix=V8-NEON
 ; RUN: llc < %s -mtriple=armv8-linux-gnueabi -mattr=+fp-armv8 -mattr=+neon | FileCheck %s --check-prefix=V8-FPARMv8-NEON
 ; RUN: llc < %s -mtriple=armv8-linux-gnueabi -mattr=+fp-armv8,+neon,+crypto | FileCheck %s --check-prefix=V8-FPARMv8-NEON-CRYPTO
-; RUN: llc < %s -mtriple=armv7-linux-gnueabi -mattr=-neon,-vfp2 | FileCheck %s --check-prefix=NOFP
 ; RUN: llc < %s -mtriple=armv7-linux-gnueabi -mcpu=cortex-a9 | FileCheck %s --check-prefix=CORTEX-A9
 ; RUN: llc < %s -mtriple=thumbv6m-linux-gnueabi -mcpu=cortex-m0 | FileCheck %s --check-prefix=CORTEX-M0
 ; RUN: llc < %s -mtriple=thumbv7m-linux-gnueabi -mcpu=cortex-m4 | FileCheck %s --check-prefix=CORTEX-M4
 ; RUN: llc < %s -mtriple=armv7r-linux-gnueabi -mcpu=cortex-r5 | FileCheck %s --check-prefix=CORTEX-R5
 ; RUN: llc < %s -mtriple=armv8-linux-gnueabi -mcpu=cortex-a53 | FileCheck %s --check-prefix=CORTEX-A53
 ; This tests that MC/asm header conversion is smooth and that build attributes are correct
 ;
 

 ; V8-FPARMv8-NEON: .eabi_attribute 12, 3
 
 ; V8-FPARMv8-NEON-CRYPTO:      .syntax unified
 ; V8-FPARMv8-NEON-CRYPTO: .eabi_attribute 6, 14
 ; V8-FPARMv8-NEON-CRYPTO: .fpu crypto-neon-fp-armv8
 ; V8-FPARMv8-NEON-CRYPTO: .eabi_attribute 10, 7
 ; V8-FPARMv8-NEON-CRYPTO: .eabi_attribute 12, 3
 
-; NOFP-NOT:   .eabi_attribute 20
-; NOFP-NOT:   .eabi_attribute 21
-; NOFP-NOT:   .eabi_attribute 23
-
 ; CORTEX-A9:  .cpu cortex-a9
 ; CORTEX-A9:  .eabi_attribute 6, 10
 ; CORTEX-A9:  .eabi_attribute 7, 65
 ; CORTEX-A9:  .eabi_attribute 8, 1
 ; CORTEX-A9:  .eabi_attribute 9, 2
 ; CORTEX-A9:  .fpu neon
 ; CORTEX-A9:  .eabi_attribute 10, 3
 ; CORTEX-A9:  .eabi_attribute 12, 1

test/CodeGen/ARM/2010-10-19-mc-elf-objheader.ll

 ;
 ; BASIC:        Section {
 ; BASIC:          Name: .ARM.attributes
 ; BASIC-NEXT:     Type: SHT_ARM_ATTRIBUTES
 ; BASIC-NEXT:     Flags [ (0x0)
 ; BASIC-NEXT:     ]
 ; BASIC-NEXT:     Address: 0x0
 ; BASIC-NEXT:     Offset: 0x3C
-; BASIC-NEXT:     Size: 24
+; BASIC-NEXT:     Size: 30
 ; BASIC-NEXT:     Link: 0
 ; BASIC-NEXT:     Info: 0
 ; BASIC-NEXT:     AddressAlignment: 1
 ; BASIC-NEXT:     EntrySize: 0
 ; BASIC-NEXT:     SectionData (
-; BASIC-NEXT:       0000: 41170000 00616561 62690001 0D000000
-; BASIC-NEXT:       0010: 06010801 18011901
+; BASIC-NEXT:       0000: 411D0000 00616561 62690001 13000000
+; BASIC-NEXT:       0010: 06010801 14011501 17031801 1901
 ; BASIC-NEXT:     )
 
 ; CORTEXA8:        Name: .ARM.attributes
 ; CORTEXA8-NEXT:     Type: SHT_ARM_ATTRIBUTES
 ; CORTEXA8-NEXT:     Flags [ (0x0)
 ; CORTEXA8-NEXT:     ]
 ; CORTEXA8-NEXT:     Address: 0x0
 ; CORTEXA8-NEXT:     Offset: 0x3C

test/MC/ARM/xscale-attributes.ll

 ; OBJ:        Section {
 ; OBJ:          Index: 4
 ; OBJ-NEXT:     Name: .ARM.attributes (12)
 ; OBJ-NEXT:     Type: SHT_ARM_ATTRIBUTES
 ; OBJ-NEXT:     Flags [ (0x0)
 ; OBJ-NEXT:     ]
 ; OBJ-NEXT:     Address: 0x0
 ; OBJ-NEXT:     Offset: 0x38
-; OBJ-NEXT:     Size: 34
+; OBJ-NEXT:     Size: 40
 ; OBJ-NEXT:     Link: 0
 ; OBJ-NEXT:     Info: 0
 ; OBJ-NEXT:     AddressAlignment: 1
 ; OBJ-NEXT:     EntrySize: 0
 ; OBJ-NEXT:     SectionData (
-; OBJ-NEXT:       0000: 41210000 00616561 62690001 17000000
-; OBJ-NEXT:       0010: 05585343 414C4500 06050801 09011801
-; OBJ-NEXT:       0020: 1901
+; OBJ-NEXT:       0000: 41270000 00616561 62690001 1D000000
+; OBJ-NEXT:       0010: 05585343 414C4500 06050801 09011401
+; OBJ-NEXT:       0020: 15011703 18011901
 ; OBJ-NEXT:     )
 ; OBJ-NEXT:   }