Move `/includes` to `/rts/include`, sort per package better

In order to make the packages in this repo "reinstallable", we need to
associate source code with a specific packages. Having a top level
`/includes` dir that mixes concerns (which packages' includes?) gets in
the way of this.

To start, I have moved everything to `rts/`, which is mostly correct.
There are a few things however that really don't belong in the rts (like
the generated constants haskell type, `CodeGen.Platform.h`). Those
needed to be manually adjusted.

Things of note:

 - No symlinking for sake of windows, so we hard-link at configure time.

 - `CodeGen.Platform.h` no longer as `.hs` extension (in addition to
   being moved to `compiler/`) so as not to confuse anyone, since it is
   next to Haskell files.

 - Blanket `-Iincludes` is gone in both build systems, include paths now
   more strictly respect per-package dependencies.

 - `deriveConstants` has been taught to not require a `--target-os` flag
   when generating the platform-agnostic Haskell type. Make takes
   advantage of this, but Hadrian has yet to.

1 files changed, 1259 insertions, 0 deletions

diff --git a/compiler/CodeGen.Platform.h b/compiler/CodeGen.Platform.h
new file mode 100644
index 0000000000..721648a900
--- /dev/null
+++ b/compiler/CodeGen.Platform.h
@@ -0,0 +1,1259 @@
+
+import GHC.Cmm.Expr
+#if !(defined(MACHREGS_i386) || defined(MACHREGS_x86_64) \
+    || defined(MACHREGS_sparc) || defined(MACHREGS_powerpc) \
+    || defined(MACHREGS_aarch64))
+import GHC.Utils.Panic.Plain
+#endif
+import GHC.Platform.Reg
+
+#include "MachRegs.h"
+
+#if defined(MACHREGS_i386) || defined(MACHREGS_x86_64)
+
+# if defined(MACHREGS_i386)
+#  define eax 0
+#  define ebx 1
+#  define ecx 2
+#  define edx 3
+#  define esi 4
+#  define edi 5
+#  define ebp 6
+#  define esp 7
+# endif
+
+# if defined(MACHREGS_x86_64)
+#  define rax   0
+#  define rbx   1
+#  define rcx   2
+#  define rdx   3
+#  define rsi   4
+#  define rdi   5
+#  define rbp   6
+#  define rsp   7
+#  define r8    8
+#  define r9    9
+#  define r10   10
+#  define r11   11
+#  define r12   12
+#  define r13   13
+#  define r14   14
+#  define r15   15
+# endif
+
+
+-- N.B. XMM, YMM, and ZMM are all aliased to the same hardware registers hence
+-- being assigned the same RegNos.
+# define xmm0  16
+# define xmm1  17
+# define xmm2  18
+# define xmm3  19
+# define xmm4  20
+# define xmm5  21
+# define xmm6  22
+# define xmm7  23
+# define xmm8  24
+# define xmm9  25
+# define xmm10 26
+# define xmm11 27
+# define xmm12 28
+# define xmm13 29
+# define xmm14 30
+# define xmm15 31
+
+# define ymm0  16
+# define ymm1  17
+# define ymm2  18
+# define ymm3  19
+# define ymm4  20
+# define ymm5  21
+# define ymm6  22
+# define ymm7  23
+# define ymm8  24
+# define ymm9  25
+# define ymm10 26
+# define ymm11 27
+# define ymm12 28
+# define ymm13 29
+# define ymm14 30
+# define ymm15 31
+
+# define zmm0  16
+# define zmm1  17
+# define zmm2  18
+# define zmm3  19
+# define zmm4  20
+# define zmm5  21
+# define zmm6  22
+# define zmm7  23
+# define zmm8  24
+# define zmm9  25
+# define zmm10 26
+# define zmm11 27
+# define zmm12 28
+# define zmm13 29
+# define zmm14 30
+# define zmm15 31
+
+-- Note: these are only needed for ARM/AArch64 because globalRegMaybe is now used in CmmSink.hs.
+-- Since it's only used to check 'isJust', the actual values don't matter, thus
+-- I'm not sure if these are the correct numberings.
+-- Normally, the register names are just stringified as part of the REG() macro
+
+#elif defined(MACHREGS_powerpc) || defined(MACHREGS_arm) \
+    || defined(MACHREGS_aarch64)
+
+# define r0 0
+# define r1 1
+# define r2 2
+# define r3 3
+# define r4 4
+# define r5 5
+# define r6 6
+# define r7 7
+# define r8 8
+# define r9 9
+# define r10 10
+# define r11 11
+# define r12 12
+# define r13 13
+# define r14 14
+# define r15 15
+# define r16 16
+# define r17 17
+# define r18 18
+# define r19 19
+# define r20 20
+# define r21 21
+# define r22 22
+# define r23 23
+# define r24 24
+# define r25 25
+# define r26 26
+# define r27 27
+# define r28 28
+# define r29 29
+# define r30 30
+# define r31 31
+
+-- See note above. These aren't actually used for anything except satisfying the compiler for globalRegMaybe
+-- so I'm unsure if they're the correct numberings, should they ever be attempted to be used in the NCG.
+#if defined(MACHREGS_aarch64) || defined(MACHREGS_arm)
+# define s0 32
+# define s1 33
+# define s2 34
+# define s3 35
+# define s4 36
+# define s5 37
+# define s6 38
+# define s7 39
+# define s8 40
+# define s9 41
+# define s10 42
+# define s11 43
+# define s12 44
+# define s13 45
+# define s14 46
+# define s15 47
+# define s16 48
+# define s17 49
+# define s18 50
+# define s19 51
+# define s20 52
+# define s21 53
+# define s22 54
+# define s23 55
+# define s24 56
+# define s25 57
+# define s26 58
+# define s27 59
+# define s28 60
+# define s29 61
+# define s30 62
+# define s31 63
+
+# define d0 32
+# define d1 33
+# define d2 34
+# define d3 35
+# define d4 36
+# define d5 37
+# define d6 38
+# define d7 39
+# define d8 40
+# define d9 41
+# define d10 42
+# define d11 43
+# define d12 44
+# define d13 45
+# define d14 46
+# define d15 47
+# define d16 48
+# define d17 49
+# define d18 50
+# define d19 51
+# define d20 52
+# define d21 53
+# define d22 54
+# define d23 55
+# define d24 56
+# define d25 57
+# define d26 58
+# define d27 59
+# define d28 60
+# define d29 61
+# define d30 62
+# define d31 63
+#endif
+
+# if defined(MACHREGS_darwin)
+#  define f0  32
+#  define f1  33
+#  define f2  34
+#  define f3  35
+#  define f4  36
+#  define f5  37
+#  define f6  38
+#  define f7  39
+#  define f8  40
+#  define f9  41
+#  define f10 42
+#  define f11 43
+#  define f12 44
+#  define f13 45
+#  define f14 46
+#  define f15 47
+#  define f16 48
+#  define f17 49
+#  define f18 50
+#  define f19 51
+#  define f20 52
+#  define f21 53
+#  define f22 54
+#  define f23 55
+#  define f24 56
+#  define f25 57
+#  define f26 58
+#  define f27 59
+#  define f28 60
+#  define f29 61
+#  define f30 62
+#  define f31 63
+# else
+#  define fr0  32
+#  define fr1  33
+#  define fr2  34
+#  define fr3  35
+#  define fr4  36
+#  define fr5  37
+#  define fr6  38
+#  define fr7  39
+#  define fr8  40
+#  define fr9  41
+#  define fr10 42
+#  define fr11 43
+#  define fr12 44
+#  define fr13 45
+#  define fr14 46
+#  define fr15 47
+#  define fr16 48
+#  define fr17 49
+#  define fr18 50
+#  define fr19 51
+#  define fr20 52
+#  define fr21 53
+#  define fr22 54
+#  define fr23 55
+#  define fr24 56
+#  define fr25 57
+#  define fr26 58
+#  define fr27 59
+#  define fr28 60
+#  define fr29 61
+#  define fr30 62
+#  define fr31 63
+# endif
+
+#elif defined(MACHREGS_sparc)
+
+# define g0  0
+# define g1  1
+# define g2  2
+# define g3  3
+# define g4  4
+# define g5  5
+# define g6  6
+# define g7  7
+
+# define o0  8
+# define o1  9
+# define o2  10
+# define o3  11
+# define o4  12
+# define o5  13
+# define o6  14
+# define o7  15
+
+# define l0  16
+# define l1  17
+# define l2  18
+# define l3  19
+# define l4  20
+# define l5  21
+# define l6  22
+# define l7  23
+
+# define i0  24
+# define i1  25
+# define i2  26
+# define i3  27
+# define i4  28
+# define i5  29
+# define i6  30
+# define i7  31
+
+# define f0  32
+# define f1  33
+# define f2  34
+# define f3  35
+# define f4  36
+# define f5  37
+# define f6  38
+# define f7  39
+# define f8  40
+# define f9  41
+# define f10 42
+# define f11 43
+# define f12 44
+# define f13 45
+# define f14 46
+# define f15 47
+# define f16 48
+# define f17 49
+# define f18 50
+# define f19 51
+# define f20 52
+# define f21 53
+# define f22 54
+# define f23 55
+# define f24 56
+# define f25 57
+# define f26 58
+# define f27 59
+# define f28 60
+# define f29 61
+# define f30 62
+# define f31 63
+
+#elif defined(MACHREGS_s390x)
+
+# define r0   0
+# define r1   1
+# define r2   2
+# define r3   3
+# define r4   4
+# define r5   5
+# define r6   6
+# define r7   7
+# define r8   8
+# define r9   9
+# define r10 10
+# define r11 11
+# define r12 12
+# define r13 13
+# define r14 14
+# define r15 15
+
+# define f0  16
+# define f1  17
+# define f2  18
+# define f3  19
+# define f4  20
+# define f5  21
+# define f6  22
+# define f7  23
+# define f8  24
+# define f9  25
+# define f10 26
+# define f11 27
+# define f12 28
+# define f13 29
+# define f14 30
+# define f15 31
+
+#elif defined(MACHREGS_riscv64)
+
+# define zero 0
+# define ra   1
+# define sp   2
+# define gp   3
+# define tp   4
+# define t0   5
+# define t1   6
+# define t2   7
+# define s0   8
+# define s1   9
+# define a0  10
+# define a1  11
+# define a2  12
+# define a3  13
+# define a4  14
+# define a5  15
+# define a6  16
+# define a7  17
+# define s2  18
+# define s3  19
+# define s4  20
+# define s5  21
+# define s6  22
+# define s7  23
+# define s8  24
+# define s9  25
+# define s10 26
+# define s11 27
+# define t3  28
+# define t4  29
+# define t5  30
+# define t6  31
+
+# define ft0  32
+# define ft1  33
+# define ft2  34
+# define ft3  35
+# define ft4  36
+# define ft5  37
+# define ft6  38
+# define ft7  39
+# define fs0  40
+# define fs1  41
+# define fa0  42
+# define fa1  43
+# define fa2  44
+# define fa3  45
+# define fa4  46
+# define fa5  47
+# define fa6  48
+# define fa7  49
+# define fs2  50
+# define fs3  51
+# define fs4  52
+# define fs5  53
+# define fs6  54
+# define fs7  55
+# define fs8  56
+# define fs9  57
+# define fs10 58
+# define fs11 59
+# define ft8  60
+# define ft9  61
+# define ft10 62
+# define ft11 63
+
+#endif
+
+callerSaves :: GlobalReg -> Bool
+#if defined(CALLER_SAVES_Base)
+callerSaves BaseReg           = True
+#endif
+#if defined(CALLER_SAVES_R1)
+callerSaves (VanillaReg 1 _)  = True
+#endif
+#if defined(CALLER_SAVES_R2)
+callerSaves (VanillaReg 2 _)  = True
+#endif
+#if defined(CALLER_SAVES_R3)
+callerSaves (VanillaReg 3 _)  = True
+#endif
+#if defined(CALLER_SAVES_R4)
+callerSaves (VanillaReg 4 _)  = True
+#endif
+#if defined(CALLER_SAVES_R5)
+callerSaves (VanillaReg 5 _)  = True
+#endif
+#if defined(CALLER_SAVES_R6)
+callerSaves (VanillaReg 6 _)  = True
+#endif
+#if defined(CALLER_SAVES_R7)
+callerSaves (VanillaReg 7 _)  = True
+#endif
+#if defined(CALLER_SAVES_R8)
+callerSaves (VanillaReg 8 _)  = True
+#endif
+#if defined(CALLER_SAVES_R9)
+callerSaves (VanillaReg 9 _)  = True
+#endif
+#if defined(CALLER_SAVES_R10)
+callerSaves (VanillaReg 10 _) = True
+#endif
+#if defined(CALLER_SAVES_F1)
+callerSaves (FloatReg 1)      = True
+#endif
+#if defined(CALLER_SAVES_F2)
+callerSaves (FloatReg 2)      = True
+#endif
+#if defined(CALLER_SAVES_F3)
+callerSaves (FloatReg 3)      = True
+#endif
+#if defined(CALLER_SAVES_F4)
+callerSaves (FloatReg 4)      = True
+#endif
+#if defined(CALLER_SAVES_F5)
+callerSaves (FloatReg 5)      = True
+#endif
+#if defined(CALLER_SAVES_F6)
+callerSaves (FloatReg 6)      = True
+#endif
+#if defined(CALLER_SAVES_D1)
+callerSaves (DoubleReg 1)     = True
+#endif
+#if defined(CALLER_SAVES_D2)
+callerSaves (DoubleReg 2)     = True
+#endif
+#if defined(CALLER_SAVES_D3)
+callerSaves (DoubleReg 3)     = True
+#endif
+#if defined(CALLER_SAVES_D4)
+callerSaves (DoubleReg 4)     = True
+#endif
+#if defined(CALLER_SAVES_D5)
+callerSaves (DoubleReg 5)     = True
+#endif
+#if defined(CALLER_SAVES_D6)
+callerSaves (DoubleReg 6)     = True
+#endif
+#if defined(CALLER_SAVES_L1)
+callerSaves (LongReg 1)       = True
+#endif
+#if defined(CALLER_SAVES_Sp)
+callerSaves Sp                = True
+#endif
+#if defined(CALLER_SAVES_SpLim)
+callerSaves SpLim             = True
+#endif
+#if defined(CALLER_SAVES_Hp)
+callerSaves Hp                = True
+#endif
+#if defined(CALLER_SAVES_HpLim)
+callerSaves HpLim             = True
+#endif
+#if defined(CALLER_SAVES_CCCS)
+callerSaves CCCS              = True
+#endif
+#if defined(CALLER_SAVES_CurrentTSO)
+callerSaves CurrentTSO        = True
+#endif
+#if defined(CALLER_SAVES_CurrentNursery)
+callerSaves CurrentNursery    = True
+#endif
+callerSaves _                 = False
+
+activeStgRegs :: [GlobalReg]
+activeStgRegs = [
+#if defined(REG_Base)
+    BaseReg
+#endif
+#if defined(REG_Sp)
+    ,Sp
+#endif
+#if defined(REG_Hp)
+    ,Hp
+#endif
+#if defined(REG_R1)
+    ,VanillaReg 1 VGcPtr
+#endif
+#if defined(REG_R2)
+    ,VanillaReg 2 VGcPtr
+#endif
+#if defined(REG_R3)
+    ,VanillaReg 3 VGcPtr
+#endif
+#if defined(REG_R4)
+    ,VanillaReg 4 VGcPtr
+#endif
+#if defined(REG_R5)
+    ,VanillaReg 5 VGcPtr
+#endif
+#if defined(REG_R6)
+    ,VanillaReg 6 VGcPtr
+#endif
+#if defined(REG_R7)
+    ,VanillaReg 7 VGcPtr
+#endif
+#if defined(REG_R8)
+    ,VanillaReg 8 VGcPtr
+#endif
+#if defined(REG_R9)
+    ,VanillaReg 9 VGcPtr
+#endif
+#if defined(REG_R10)
+    ,VanillaReg 10 VGcPtr
+#endif
+#if defined(REG_SpLim)
+    ,SpLim
+#endif
+#if MAX_REAL_XMM_REG != 0
+#if defined(REG_F1)
+    ,FloatReg 1
+#endif
+#if defined(REG_D1)
+    ,DoubleReg 1
+#endif
+#if defined(REG_XMM1)
+    ,XmmReg 1
+#endif
+#if defined(REG_YMM1)
+    ,YmmReg 1
+#endif
+#if defined(REG_ZMM1)
+    ,ZmmReg 1
+#endif
+#if defined(REG_F2)
+    ,FloatReg 2
+#endif
+#if defined(REG_D2)
+    ,DoubleReg 2
+#endif
+#if defined(REG_XMM2)
+    ,XmmReg 2
+#endif
+#if defined(REG_YMM2)
+    ,YmmReg 2
+#endif
+#if defined(REG_ZMM2)
+    ,ZmmReg 2
+#endif
+#if defined(REG_F3)
+    ,FloatReg 3
+#endif
+#if defined(REG_D3)
+    ,DoubleReg 3
+#endif
+#if defined(REG_XMM3)
+    ,XmmReg 3
+#endif
+#if defined(REG_YMM3)
+    ,YmmReg 3
+#endif
+#if defined(REG_ZMM3)
+    ,ZmmReg 3
+#endif
+#if defined(REG_F4)
+    ,FloatReg 4
+#endif
+#if defined(REG_D4)
+    ,DoubleReg 4
+#endif
+#if defined(REG_XMM4)
+    ,XmmReg 4
+#endif
+#if defined(REG_YMM4)
+    ,YmmReg 4
+#endif
+#if defined(REG_ZMM4)
+    ,ZmmReg 4
+#endif
+#if defined(REG_F5)
+    ,FloatReg 5
+#endif
+#if defined(REG_D5)
+    ,DoubleReg 5
+#endif
+#if defined(REG_XMM5)
+    ,XmmReg 5
+#endif
+#if defined(REG_YMM5)
+    ,YmmReg 5
+#endif
+#if defined(REG_ZMM5)
+    ,ZmmReg 5
+#endif
+#if defined(REG_F6)
+    ,FloatReg 6
+#endif
+#if defined(REG_D6)
+    ,DoubleReg 6
+#endif
+#if defined(REG_XMM6)
+    ,XmmReg 6
+#endif
+#if defined(REG_YMM6)
+    ,YmmReg 6
+#endif
+#if defined(REG_ZMM6)
+    ,ZmmReg 6
+#endif
+#else /* MAX_REAL_XMM_REG == 0 */
+#if defined(REG_F1)
+    ,FloatReg 1
+#endif
+#if defined(REG_F2)
+    ,FloatReg 2
+#endif
+#if defined(REG_F3)
+    ,FloatReg 3
+#endif
+#if defined(REG_F4)
+    ,FloatReg 4
+#endif
+#if defined(REG_F5)
+    ,FloatReg 5
+#endif
+#if defined(REG_F6)
+    ,FloatReg 6
+#endif
+#if defined(REG_D1)
+    ,DoubleReg 1
+#endif
+#if defined(REG_D2)
+    ,DoubleReg 2
+#endif
+#if defined(REG_D3)
+    ,DoubleReg 3
+#endif
+#if defined(REG_D4)
+    ,DoubleReg 4
+#endif
+#if defined(REG_D5)
+    ,DoubleReg 5
+#endif
+#if defined(REG_D6)
+    ,DoubleReg 6
+#endif
+#endif /* MAX_REAL_XMM_REG == 0 */
+    ]
+
+haveRegBase :: Bool
+#if defined(REG_Base)
+haveRegBase = True
+#else
+haveRegBase = False
+#endif
+
+--  | Returns 'Nothing' if this global register is not stored
+-- in a real machine register, otherwise returns @'Just' reg@, where
+-- reg is the machine register it is stored in.
+globalRegMaybe :: GlobalReg -> Maybe RealReg
+#if defined(MACHREGS_i386) || defined(MACHREGS_x86_64) \
+    || defined(MACHREGS_sparc) || defined(MACHREGS_powerpc) \
+    || defined(MACHREGS_arm) || defined(MACHREGS_aarch64) \
+    || defined(MACHREGS_s390x) || defined(MACHREGS_riscv64)
+# if defined(REG_Base)
+globalRegMaybe BaseReg                  = Just (RealRegSingle REG_Base)
+# endif
+# if defined(REG_R1)
+globalRegMaybe (VanillaReg 1 _)         = Just (RealRegSingle REG_R1)
+# endif
+# if defined(REG_R2)
+globalRegMaybe (VanillaReg 2 _)         = Just (RealRegSingle REG_R2)
+# endif
+# if defined(REG_R3)
+globalRegMaybe (VanillaReg 3 _)         = Just (RealRegSingle REG_R3)
+# endif
+# if defined(REG_R4)
+globalRegMaybe (VanillaReg 4 _)         = Just (RealRegSingle REG_R4)
+# endif
+# if defined(REG_R5)
+globalRegMaybe (VanillaReg 5 _)         = Just (RealRegSingle REG_R5)
+# endif
+# if defined(REG_R6)
+globalRegMaybe (VanillaReg 6 _)         = Just (RealRegSingle REG_R6)
+# endif
+# if defined(REG_R7)
+globalRegMaybe (VanillaReg 7 _)         = Just (RealRegSingle REG_R7)
+# endif
+# if defined(REG_R8)
+globalRegMaybe (VanillaReg 8 _)         = Just (RealRegSingle REG_R8)
+# endif
+# if defined(REG_R9)
+globalRegMaybe (VanillaReg 9 _)         = Just (RealRegSingle REG_R9)
+# endif
+# if defined(REG_R10)
+globalRegMaybe (VanillaReg 10 _)        = Just (RealRegSingle REG_R10)
+# endif
+# if defined(REG_F1)
+globalRegMaybe (FloatReg 1)             = Just (RealRegSingle REG_F1)
+# endif
+# if defined(REG_F2)
+globalRegMaybe (FloatReg 2)             = Just (RealRegSingle REG_F2)
+# endif
+# if defined(REG_F3)
+globalRegMaybe (FloatReg 3)             = Just (RealRegSingle REG_F3)
+# endif
+# if defined(REG_F4)
+globalRegMaybe (FloatReg 4)             = Just (RealRegSingle REG_F4)
+# endif
+# if defined(REG_F5)
+globalRegMaybe (FloatReg 5)             = Just (RealRegSingle REG_F5)
+# endif
+# if defined(REG_F6)
+globalRegMaybe (FloatReg 6)             = Just (RealRegSingle REG_F6)
+# endif
+# if defined(REG_D1)
+globalRegMaybe (DoubleReg 1)            =
+#  if defined(MACHREGS_sparc)
+                                          Just (RealRegPair REG_D1 (REG_D1 + 1))
+#  else
+                                          Just (RealRegSingle REG_D1)
+#  endif
+# endif
+# if defined(REG_D2)
+globalRegMaybe (DoubleReg 2)            =
+#  if defined(MACHREGS_sparc)
+                                          Just (RealRegPair REG_D2 (REG_D2 + 1))
+#  else
+                                          Just (RealRegSingle REG_D2)
+#  endif
+# endif
+# if defined(REG_D3)
+globalRegMaybe (DoubleReg 3)            =
+#  if defined(MACHREGS_sparc)
+                                          Just (RealRegPair REG_D3 (REG_D3 + 1))
+#  else
+                                          Just (RealRegSingle REG_D3)
+#  endif
+# endif
+# if defined(REG_D4)
+globalRegMaybe (DoubleReg 4)            =
+#  if defined(MACHREGS_sparc)
+                                          Just (RealRegPair REG_D4 (REG_D4 + 1))
+#  else
+                                          Just (RealRegSingle REG_D4)
+#  endif
+# endif
+# if defined(REG_D5)
+globalRegMaybe (DoubleReg 5)            =
+#  if defined(MACHREGS_sparc)
+                                          Just (RealRegPair REG_D5 (REG_D5 + 1))
+#  else
+                                          Just (RealRegSingle REG_D5)
+#  endif
+# endif
+# if defined(REG_D6)
+globalRegMaybe (DoubleReg 6)            =
+#  if defined(MACHREGS_sparc)
+                                          Just (RealRegPair REG_D6 (REG_D6 + 1))
+#  else
+                                          Just (RealRegSingle REG_D6)
+#  endif
+# endif
+# if MAX_REAL_XMM_REG != 0
+#  if defined(REG_XMM1)
+globalRegMaybe (XmmReg 1)               = Just (RealRegSingle REG_XMM1)
+#  endif
+#  if defined(REG_XMM2)
+globalRegMaybe (XmmReg 2)               = Just (RealRegSingle REG_XMM2)
+#  endif
+#  if defined(REG_XMM3)
+globalRegMaybe (XmmReg 3)               = Just (RealRegSingle REG_XMM3)
+#  endif
+#  if defined(REG_XMM4)
+globalRegMaybe (XmmReg 4)               = Just (RealRegSingle REG_XMM4)
+#  endif
+#  if defined(REG_XMM5)
+globalRegMaybe (XmmReg 5)               = Just (RealRegSingle REG_XMM5)
+#  endif
+#  if defined(REG_XMM6)
+globalRegMaybe (XmmReg 6)               = Just (RealRegSingle REG_XMM6)
+#  endif
+# endif
+# if defined(MAX_REAL_YMM_REG) && MAX_REAL_YMM_REG != 0
+#  if defined(REG_YMM1)
+globalRegMaybe (YmmReg 1)               = Just (RealRegSingle REG_YMM1)
+#  endif
+#  if defined(REG_YMM2)
+globalRegMaybe (YmmReg 2)               = Just (RealRegSingle REG_YMM2)
+#  endif
+#  if defined(REG_YMM3)
+globalRegMaybe (YmmReg 3)               = Just (RealRegSingle REG_YMM3)
+#  endif
+#  if defined(REG_YMM4)
+globalRegMaybe (YmmReg 4)               = Just (RealRegSingle REG_YMM4)
+#  endif
+#  if defined(REG_YMM5)
+globalRegMaybe (YmmReg 5)               = Just (RealRegSingle REG_YMM5)
+#  endif
+#  if defined(REG_YMM6)
+globalRegMaybe (YmmReg 6)               = Just (RealRegSingle REG_YMM6)
+#  endif
+# endif
+# if defined(MAX_REAL_ZMM_REG) && MAX_REAL_ZMM_REG != 0
+#  if defined(REG_ZMM1)
+globalRegMaybe (ZmmReg 1)               = Just (RealRegSingle REG_ZMM1)
+#  endif
+#  if defined(REG_ZMM2)
+globalRegMaybe (ZmmReg 2)               = Just (RealRegSingle REG_ZMM2)
+#  endif
+#  if defined(REG_ZMM3)
+globalRegMaybe (ZmmReg 3)               = Just (RealRegSingle REG_ZMM3)
+#  endif
+#  if defined(REG_ZMM4)
+globalRegMaybe (ZmmReg 4)               = Just (RealRegSingle REG_ZMM4)
+#  endif
+#  if defined(REG_ZMM5)
+globalRegMaybe (ZmmReg 5)               = Just (RealRegSingle REG_ZMM5)
+#  endif
+#  if defined(REG_ZMM6)
+globalRegMaybe (ZmmReg 6)               = Just (RealRegSingle REG_ZMM6)
+#  endif
+# endif
+# if defined(REG_Sp)
+globalRegMaybe Sp                       = Just (RealRegSingle REG_Sp)
+# endif
+# if defined(REG_Lng1)
+globalRegMaybe (LongReg 1)              = Just (RealRegSingle REG_Lng1)
+# endif
+# if defined(REG_Lng2)
+globalRegMaybe (LongReg 2)              = Just (RealRegSingle REG_Lng2)
+# endif
+# if defined(REG_SpLim)
+globalRegMaybe SpLim                    = Just (RealRegSingle REG_SpLim)
+# endif
+# if defined(REG_Hp)
+globalRegMaybe Hp                       = Just (RealRegSingle REG_Hp)
+# endif
+# if defined(REG_HpLim)
+globalRegMaybe HpLim                    = Just (RealRegSingle REG_HpLim)
+# endif
+# if defined(REG_CurrentTSO)
+globalRegMaybe CurrentTSO               = Just (RealRegSingle REG_CurrentTSO)
+# endif
+# if defined(REG_CurrentNursery)
+globalRegMaybe CurrentNursery           = Just (RealRegSingle REG_CurrentNursery)
+# endif
+# if defined(REG_MachSp)
+globalRegMaybe MachSp                   = Just (RealRegSingle REG_MachSp)
+# endif
+globalRegMaybe _                        = Nothing
+#elif defined(MACHREGS_NO_REGS)
+globalRegMaybe _ = Nothing
+#else
+globalRegMaybe = panic "globalRegMaybe not defined for this platform"
+#endif
+
+freeReg :: RegNo -> Bool
+
+#if defined(MACHREGS_i386) || defined(MACHREGS_x86_64)
+
+# if defined(MACHREGS_i386)
+freeReg esp = False -- %esp is the C stack pointer
+freeReg esi = False -- Note [esi/edi/ebp not allocatable]
+freeReg edi = False
+freeReg ebp = False
+# endif
+# if defined(MACHREGS_x86_64)
+freeReg rsp = False  --        %rsp is the C stack pointer
+# endif
+
+{-
+Note [esi/edi/ebp not allocatable]
+
+%esi is mapped to R1, so %esi would normally be allocatable while it
+is not being used for R1.  However, %esi has no 8-bit version on x86,
+and the linear register allocator is not sophisticated enough to
+handle this irregularity (we need more RegClasses).  The
+graph-colouring allocator also cannot handle this - it was designed
+with more flexibility in mind, but the current implementation is
+restricted to the same set of classes as the linear allocator.
+
+Hence, on x86 esi, edi and ebp are treated as not allocatable.
+-}
+
+-- split patterns in two functions to prevent overlaps
+freeReg r         = freeRegBase r
+
+freeRegBase :: RegNo -> Bool
+# if defined(REG_Base)
+freeRegBase REG_Base  = False
+# endif
+# if defined(REG_Sp)
+freeRegBase REG_Sp    = False
+# endif
+# if defined(REG_SpLim)
+freeRegBase REG_SpLim = False
+# endif
+# if defined(REG_Hp)
+freeRegBase REG_Hp    = False
+# endif
+# if defined(REG_HpLim)
+freeRegBase REG_HpLim = False
+# endif
+-- All other regs are considered to be "free", because we can track
+-- their liveness accurately.
+freeRegBase _ = True
+
+#elif defined(MACHREGS_powerpc)
+
+freeReg 0 = False -- Used by code setting the back chain pointer
+                  -- in stack reallocations on Linux.
+                  -- Moreover r0 is not usable in all insns.
+freeReg 1 = False -- The Stack Pointer
+-- most ELF PowerPC OSes use r2 as a TOC pointer
+freeReg 2 = False
+freeReg 13 = False -- reserved for system thread ID on 64 bit
+-- at least linux in -fPIC relies on r30 in PLT stubs
+freeReg 30 = False
+{- TODO: reserve r13 on 64 bit systems only and r30 on 32 bit respectively.
+   For now we use r30 on 64 bit and r13 on 32 bit as a temporary register
+   in stack handling code. See compiler/GHC/CmmToAsm/PPC/Instr.hs.
+
+   Later we might want to reserve r13 and r30 only where it is required.
+   Then use r12 as temporary register, which is also what the C ABI does.
+-}
+
+# if defined(REG_Base)
+freeReg REG_Base  = False
+# endif
+# if defined(REG_Sp)
+freeReg REG_Sp    = False
+# endif
+# if defined(REG_SpLim)
+freeReg REG_SpLim = False
+# endif
+# if defined(REG_Hp)
+freeReg REG_Hp    = False
+# endif
+# if defined(REG_HpLim)
+freeReg REG_HpLim = False
+# endif
+freeReg _ = True
+
+#elif defined(MACHREGS_aarch64)
+
+-- stack pointer / zero reg
+freeReg 31 = False
+-- link register
+freeReg 30 = False
+-- frame pointer
+freeReg 29 = False
+-- ip0 -- used for spill offset computations
+freeReg 16 = False
+
+# if defined(REG_Base)
+freeReg REG_Base  = False
+# endif
+# if defined(REG_Sp)
+freeReg REG_Sp    = False
+# endif
+# if defined(REG_SpLim)
+freeReg REG_SpLim = False
+# endif
+# if defined(REG_Hp)
+freeReg REG_Hp    = False
+# endif
+# if defined(REG_HpLim)
+freeReg REG_HpLim = False
+# endif
+
+# if defined(REG_R1)
+freeReg REG_R1    = False
+# endif
+# if defined(REG_R2)
+freeReg REG_R2    = False
+# endif
+# if defined(REG_R3)
+freeReg REG_R3    = False
+# endif
+# if defined(REG_R4)
+freeReg REG_R4    = False
+# endif
+# if defined(REG_R5)
+freeReg REG_R5    = False
+# endif
+# if defined(REG_R6)
+freeReg REG_R6    = False
+# endif
+# if defined(REG_R7)
+freeReg REG_R7    = False
+# endif
+# if defined(REG_R8)
+freeReg REG_R8    = False
+# endif
+
+# if defined(REG_F1)
+freeReg REG_F1    = False
+# endif
+# if defined(REG_F2)
+freeReg REG_F2    = False
+# endif
+# if defined(REG_F3)
+freeReg REG_F3    = False
+# endif
+# if defined(REG_F4)
+freeReg REG_F4    = False
+# endif
+# if defined(REG_F5)
+freeReg REG_F5    = False
+# endif
+# if defined(REG_F6)
+freeReg REG_F6    = False
+# endif
+
+# if defined(REG_D1)
+freeReg REG_D1    = False
+# endif
+# if defined(REG_D2)
+freeReg REG_D2    = False
+# endif
+# if defined(REG_D3)
+freeReg REG_D3    = False
+# endif
+# if defined(REG_D4)
+freeReg REG_D4    = False
+# endif
+# if defined(REG_D5)
+freeReg REG_D5    = False
+# endif
+# if defined(REG_D6)
+freeReg REG_D6    = False
+# endif
+
+freeReg _ = True
+
+#elif defined(MACHREGS_sparc)
+
+-- SPARC regs used by the OS / ABI
+-- %g0(r0) is always zero
+freeReg g0  = False
+
+-- %g5(r5) - %g7(r7)
+--  are reserved for the OS
+freeReg g5  = False
+freeReg g6  = False
+freeReg g7  = False
+
+-- %o6(r14)
+--  is the C stack pointer
+freeReg o6  = False
+
+-- %o7(r15)
+--  holds the C return address
+freeReg o7  = False
+
+-- %i6(r30)
+--  is the C frame pointer
+freeReg i6  = False
+
+-- %i7(r31)
+--  is used for C return addresses
+freeReg i7  = False
+
+-- %f0(r32) - %f1(r32)
+--  are C floating point return regs
+freeReg f0  = False
+freeReg f1  = False
+
+{-
+freeReg regNo
+    -- don't release high half of double regs
+    | regNo >= f0
+    , regNo <  NCG_FirstFloatReg
+    , regNo `mod` 2 /= 0
+    = False
+-}
+
+# if defined(REG_Base)
+freeReg REG_Base  = False
+# endif
+# if defined(REG_R1)
+freeReg REG_R1    = False
+# endif
+# if defined(REG_R2)
+freeReg REG_R2    = False
+# endif
+# if defined(REG_R3)
+freeReg REG_R3    = False
+# endif
+# if defined(REG_R4)
+freeReg REG_R4    = False
+# endif
+# if defined(REG_R5)
+freeReg REG_R5    = False
+# endif
+# if defined(REG_R6)
+freeReg REG_R6    = False
+# endif
+# if defined(REG_R7)
+freeReg REG_R7    = False
+# endif
+# if defined(REG_R8)
+freeReg REG_R8    = False
+# endif
+# if defined(REG_R9)
+freeReg REG_R9    = False
+# endif
+# if defined(REG_R10)
+freeReg REG_R10   = False
+# endif
+# if defined(REG_F1)
+freeReg REG_F1    = False
+# endif
+# if defined(REG_F2)
+freeReg REG_F2    = False
+# endif
+# if defined(REG_F3)
+freeReg REG_F3    = False
+# endif
+# if defined(REG_F4)
+freeReg REG_F4    = False
+# endif
+# if defined(REG_F5)
+freeReg REG_F5    = False
+# endif
+# if defined(REG_F6)
+freeReg REG_F6    = False
+# endif
+# if defined(REG_D1)
+freeReg REG_D1    = False
+# endif
+# if defined(REG_D1_2)
+freeReg REG_D1_2  = False
+# endif
+# if defined(REG_D2)
+freeReg REG_D2    = False
+# endif
+# if defined(REG_D2_2)
+freeReg REG_D2_2  = False
+# endif
+# if defined(REG_D3)
+freeReg REG_D3    = False
+# endif
+# if defined(REG_D3_2)
+freeReg REG_D3_2  = False
+# endif
+# if defined(REG_D4)
+freeReg REG_D4    = False
+# endif
+# if defined(REG_D4_2)
+freeReg REG_D4_2  = False
+# endif
+# if defined(REG_D5)
+freeReg REG_D5    = False
+# endif
+# if defined(REG_D5_2)
+freeReg REG_D5_2  = False
+# endif
+# if defined(REG_D6)
+freeReg REG_D6    = False
+# endif
+# if defined(REG_D6_2)
+freeReg REG_D6_2  = False
+# endif
+# if defined(REG_Sp)
+freeReg REG_Sp    = False
+# endif
+# if defined(REG_SpLim)
+freeReg REG_SpLim = False
+# endif
+# if defined(REG_Hp)
+freeReg REG_Hp    = False
+# endif
+# if defined(REG_HpLim)
+freeReg REG_HpLim = False
+# endif
+freeReg _ = True
+
+#else
+
+freeReg = panic "freeReg not defined for this platform"
+
+#endif