For arm, chooses hard vs. soft fp ABI based on compiler.

runtime/vm/cpu_arm.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"
 #if defined(TARGET_ARCH_ARM)
 
 #include "vm/assembler.h"
 #include "vm/cpu.h"
 #include "vm/cpuinfo.h"
 #include "vm/heap.h"
 #include "vm/isolate.h"
 #include "vm/object.h"
 #include "vm/simulator.h"
 #include "vm/thread.h"
 
 #if defined(HOST_ARCH_ARM)
 #include <sys/syscall.h>  /* NOLINT */
 #include <unistd.h>  /* NOLINT */
 #endif
 
 namespace dart {
 
 DEFINE_FLAG(bool, use_vfp, true, "Use vfp instructions if supported");
 DEFINE_FLAG(bool, use_neon, true, "Use neon instructions if supported");
 #if !defined(HOST_ARCH_ARM)
 DEFINE_FLAG(bool, sim_use_armv7, true, "Use all ARMv7 instructions");
 DEFINE_FLAG(bool, sim_use_armv5te, false, "Restrict to ARMv5TE instructions");
 DEFINE_FLAG(bool, sim_use_armv6, false, "Restrict to ARMv6 instructions");
+DEFINE_FLAG(bool, sim_use_hardfp, false, "Use the softfp ABI.");
 #endif
 
 void CPU::FlushICache(uword start, uword size) {
 #if defined(HOST_ARCH_ARM)
   // Nothing to do. Flushing no instructions.
   if (size == 0) {
     return;
   }
 
   // ARM recommends using the gcc intrinsic __clear_cache on Linux, and the
@@ skipping 19 matching lines @@
 #if !defined(HOST_ARCH_ARM)
   "sim"
 #endif  // !defined(HOST_ARCH_ARM)
   "arm";
 }
 
 
 bool HostCPUFeatures::integer_division_supported_ = false;
 bool HostCPUFeatures::vfp_supported_ = false;
 bool HostCPUFeatures::neon_supported_ = false;
+bool HostCPUFeatures::hardfp_supported_ = false;
 const char* HostCPUFeatures::hardware_ = NULL;
 ARMVersion HostCPUFeatures::arm_version_ = ARMvUnknown;
 #if defined(DEBUG)
 bool HostCPUFeatures::initialized_ = false;
 #endif
 
 
 #if defined(HOST_ARCH_ARM)
 void HostCPUFeatures::InitOnce() {
   CpuInfo::InitOnce();
@@ skipping 23 matching lines @@
   bool is_krait = CpuInfo::FieldContains(kCpuInfoHardware, "QCT APQ8064");
   if (is_krait) {
     // Special case for Qualcomm Krait CPUs in Nexus 4 and 7.
     integer_division_supported_ = true;
   } else {
     integer_division_supported_ =
         CpuInfo::FieldContains(kCpuInfoFeatures, "idiva");
   }
   neon_supported_ = CpuInfo::FieldContains(kCpuInfoFeatures, "neon") &&
                     FLAG_use_vfp && FLAG_use_neon;
+
+  // Use the cross-compiler's predefined macros to determine whether we should
+  // use the hard or soft float ABI.
+#if defined(__ARM_PCS_VFP)
+  hardfp_supported_ = true;
+#else
+  hardfp_supported_ = false;
+#endif
+
 #if defined(DEBUG)
   initialized_ = true;
 #endif
 }
 
 
 void HostCPUFeatures::Cleanup() {
   DEBUG_ASSERT(initialized_);
 #if defined(DEBUG)
   initialized_ = false;
 #endif
   ASSERT(hardware_ != NULL);
   free(const_cast<char*>(hardware_));
   hardware_ = NULL;
   CpuInfo::Cleanup();
 }
 
 #else
 
 void HostCPUFeatures::InitOnce() {
   CpuInfo::InitOnce();
   hardware_ = CpuInfo::GetCpuModel();
   vfp_supported_ = FLAG_use_vfp;
   neon_supported_ = FLAG_use_vfp && FLAG_use_neon;
-  integer_division_supported_ = true;
+  hardfp_supported_ = FLAG_sim_use_hardfp;
   if (FLAG_sim_use_armv5te) {
     arm_version_ = ARMv5TE;
+    integer_division_supported_ = false;
   } else if (FLAG_sim_use_armv6) {
     arm_version_ = ARMv6;
+    integer_division_supported_ = true;
   } else if (FLAG_sim_use_armv7) {
     arm_version_ = ARMv7;
+    integer_division_supported_ = true;
   }
 #if defined(DEBUG)
   initialized_ = true;
 #endif
 }
 
 
 void HostCPUFeatures::Cleanup() {
   DEBUG_ASSERT(initialized_);
 #if defined(DEBUG)
   initialized_ = false;
 #endif
   ASSERT(hardware_ != NULL);
   free(const_cast<char*>(hardware_));
   hardware_ = NULL;
   CpuInfo::Cleanup();
 }
 #endif  // defined(HOST_ARCH_ARM)
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM