Don't assume we want the iOS ABI if running simarm on Mac and the EABI otherwise.

runtime/vm/constants_arm.h

 // Copyright (c) 2013, 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.
 
 #ifndef VM_CONSTANTS_ARM_H_
 #define VM_CONSTANTS_ARM_H_
 
 #include "platform/globals.h"
 #include "platform/assert.h"
 
 namespace dart {
 
 // We support both VFPv3-D16 and VFPv3-D32 profiles, but currently only one at
 // a time.
 #if defined(__ARM_ARCH_7A__)
 #define VFPv3_D32
 #elif defined(TARGET_ARCH_ARM) && !defined(HOST_ARCH_ARM)
 // If we're running in the simulator, use all 32.
 #define VFPv3_D32
 #else
 #define VFPv3_D16
 #endif
 #if defined(VFPv3_D16) == defined(VFPv3_D32)
 #error "Exactly one of VFPv3_D16 or VFPv3_D32 can be defined at a time."
 #endif
 
 
+// The Linux/Android ABI and the iOS ABI differ in their choice of frame
+// pointer, their treatment of R9, and the interproduceral stack alignment.
+
+// EABI (Linux, Android)
+// See "Procedure Call Standard for the ARM Architecture".
+// R0-R1:  Argument / result / volatile
+// R2-R3:  Argument / volatile
+// R4-R10: Preserved
+// R11:    Frame pointer
+// R12:    Volatile
+// R13:    Stack pointer
+// R14:    Link register
+// R15:    Program counter
+// Stack alignment: 4 bytes always, 8 bytes at public interfaces
+
+// Linux (Debian armhf) and Android also differ in whether floating point
+// arguments are passed in registers. Linux uses hardfp and Android uses
+// softfp. See TargetCPUFeatures::hardfp_supported().
+
+// iOS ABI
+// See "iOS ABI Function Call Guide"
+// R0-R1: Argument / result / volatile
+// R2-R3: Argument / volatile
+// R4-R6: Preserved
+// R7:    Frame pointer
+// R8-R9: Preserved
+// R12:   Volatile
+// R13:   Stack pointer
+// R14:   Link register
+// R15:   Program counter
+// Stack alignment: 4 bytes always, 4 bytes at public interfaces
+
+// iOS passes floating point arguments in registers (hardfp)
+
+
 enum Register {
   R0  =  0,
   R1  =  1,
   R2  =  2,
   R3  =  3,
   R4  =  4,
   R5  =  5,  // PP
   R6  =  6,  // CTX
   R7  =  7,  // iOS FP
   R8  =  8,
   R9  =  9,
   R10 = 10,  // THR
   R11 = 11,  // Linux FP
   R12 = 12,  // IP aka TMP
   R13 = 13,  // SP
   R14 = 14,  // LR
   R15 = 15,  // PC
   kNumberOfCpuRegisters = 16,
   kNoRegister = -1,  // Signals an illegal register.
 
   // Aliases.
-#if defined(TARGET_OS_MACOS)
+#if defined(TARGET_ABI_IOS)
   FP   = R7,
   NOTFP = R11,
-#else
+#elif defined(TARGET_ABI_EABI)
   FP   = R11,
   NOTFP = R7,
+#else
+#error Unknown ABI
 #endif
   IP  = R12,
   SP  = R13,
   LR  = R14,
   PC  = R15,
 };
 
 
 // Values for single-precision floating point registers.
 enum SRegister {
@@ skipping 196 matching lines @@
 
 
 // List of registers used in load/store multiple.
 typedef uint16_t RegList;
 const RegList kAllCpuRegistersList = 0xFFFF;
 
 
 // C++ ABI call registers.
 const RegList kAbiArgumentCpuRegs =
     (1 << R0) | (1 << R1) | (1 << R2) | (1 << R3);
-#if defined(TARGET_OS_MACOS)
+#if defined(TARGET_ABI_IOS)
 const RegList kAbiPreservedCpuRegs =
     (1 << R4)  | (1 << R5) | (1 << R6) | (1 << R8) |
     (1 << R10) | (1 << R11);
 const int kAbiPreservedCpuRegCount = 6;
-#else
+#elif defined(TARGET_ABI_EABI)
 const RegList kAbiPreservedCpuRegs =
     (1 << R4) | (1 << R5) | (1 << R6) | (1 << R7) |
     (1 << R8) | (1 << R9) | (1 << R10);
 const int kAbiPreservedCpuRegCount = 7;
+#else
+#error Unknown ABI
 #endif
 const QRegister kAbiFirstPreservedFpuReg = Q4;
 const QRegister kAbiLastPreservedFpuReg = Q7;
 const int kAbiPreservedFpuRegCount = 4;
 
 const RegList kReservedCpuRegisters =
     (1 << SPREG) |
     (1 << FPREG) |
     (1 << TMP)   |
     (1 << PP)    |
     (1 << THR)   |
     (1 << PC);
 // CPU registers available to Dart allocator.
 const RegList kDartAvailableCpuRegs =
     kAllCpuRegistersList & ~kReservedCpuRegisters;
 // Registers available to Dart that are not preserved by runtime calls.
 const RegList kDartVolatileCpuRegs =
     kDartAvailableCpuRegs & ~kAbiPreservedCpuRegs;
-#if defined(TARGET_OS_MACOS)
+#if defined(TARGET_ABI_IOS)
 const int kDartVolatileCpuRegCount = 6;
-#else
+#elif defined(TARGET_ABI_EABI)
 const int kDartVolatileCpuRegCount = 5;
 #endif
 const QRegister kDartFirstVolatileFpuReg = Q0;
 const QRegister kDartLastVolatileFpuReg = Q3;
 const int kDartVolatileFpuRegCount = 4;
 
 
 // Values for the condition field as defined in section A3.2.
 enum Condition {
   kNoCondition = -1,
@@ skipping 417 matching lines @@
   static Instr* At(uword pc) { return reinterpret_cast<Instr*>(pc); }
 
  private:
   DISALLOW_ALLOCATION();
   DISALLOW_IMPLICIT_CONSTRUCTORS(Instr);
 };
 
 }  // namespace dart
 
 #endif  // VM_CONSTANTS_ARM_H_