Global allocator support

[bjorn3]

Getting a linker error (branch wip_alloc_example):

target/debug/xargo(data.o): In function `__rg_realloc':
some_file.o:(.text.__rg_realloc+0x56): undefined reference to `core::alloc::Layout::from_size_align_unchecked'
some_file.o:(.text.__rg_realloc+0x84): undefined reference to `alloc_system::platform::<impl core::alloc::GlobalAlloc for alloc_system::System>::realloc'
target/debug/xargo(data.o): In function `xargo::main':
some_file.o:(.text._ZN5xargo4main17h7ba4cb1b7386fe5eE+0x7f): undefined reference to `alloc::alloc::exchange_malloc'
target/debug/xargo(data.o): In function `core::ptr::drop_in_place':
some_file.o:(.text._ZN4core3ptr13drop_in_place17hefa8a925b43607b3E+0xc): undefined reference to `alloc::alloc::box_free'
target/debug/xargo(data.o): In function `__rg_dealloc':
some_file.o:(.text.__rg_dealloc+0x3c): undefined reference to `core::alloc::Layout::from_size_align_unchecked'
some_file.o:(.text.__rg_dealloc+0x5f): undefined reference to `alloc_system::platform::<impl core::alloc::GlobalAlloc for alloc_system::System>::dealloc'
target/debug/xargo(data.o): In function `__rg_alloc':
some_file.o:(.text.__rg_alloc+0x4a): undefined reference to `core::alloc::Layout::from_size_align_unchecked'
some_file.o:(.text.__rg_alloc+0x65): undefined reference to `alloc_system::platform::<impl core::alloc::GlobalAlloc for alloc_system::System>::alloc'
target/debug/xargo(data.o): In function `__rg_alloc_zeroed':
some_file.o:(.text.__rg_alloc_zeroed+0x4a): undefined reference to `core::alloc::Layout::from_size_align_unchecked'
some_file.o:(.text.__rg_alloc_zeroed+0x65): undefined reference to `alloc_system::platform::<impl core::alloc::GlobalAlloc for alloc_system::System>::alloc_zeroed'

[bjorn3]

At least alloc::alloc::exchange_malloc exists in liballoc with exactly the same full symbol name including hash.

[bjorn3]

Symbols from rustc_codegen_cranelift:

$ nm xargo/target/debug/xargo

xargo/target/debug/xargo(data.o):
000000000000043d d _0
000000000000042d d _3
                 U __ZN12alloc_system8platform75_$LT$impl$u20$core..alloc..GlobalAlloc$u20$for$u20$alloc_system..System$GT$12alloc_zeroed17h79368c8eb8fc6e8eE
                 U __ZN12alloc_system8platform75_$LT$impl$u20$core..alloc..GlobalAlloc$u20$for$u20$alloc_system..System$GT$5alloc17h4ed6afcc55fd971dE
                 U __ZN12alloc_system8platform75_$LT$impl$u20$core..alloc..GlobalAlloc$u20$for$u20$alloc_system..System$GT$7dealloc17h1e69e6d3ecea17e7E
                 U __ZN12alloc_system8platform75_$LT$impl$u20$core..alloc..GlobalAlloc$u20$for$u20$alloc_system..System$GT$7realloc17he7eabe075503b093E
00000000000002e0 T __ZN4core3ptr13drop_in_place17hbfa94f7f536f4f1aE
                 U __ZN4core5alloc6Layout25from_size_align_unchecked17hf2ead6bf6994c8b9E
                 U __ZN5alloc5alloc15exchange_malloc17he4ad6b3b3fe9e17dE
                 U __ZN5alloc5alloc8box_free17h3b1e85a33b3d2dbcE
0000000000000118 T __ZN5xargo4main17ha4fe8a15b487d3a2E
000000000000044a D __ZN5xargo5ALLOC17hacdde07616dc6e79E
000000000000039a T ___rg_alloc
00000000000002f3 T ___rg_alloc_zeroed
00000000000000ae T ___rg_dealloc
0000000000000000 T ___rg_realloc
0000000000000420 T _main
                 U _puts
00000000000000a7 T _rust_begin_unwind
0000000000000379 T _rust_oom

Symbols from rustc_codegen_llvm (tricked into using rlibs compiled by rustc_codegen_cranelift):

$ nm xargo/target/debug/deps/xargo-1eae7525e610cc5d.3p4fkhb6ukg309zl.rcgu.o
                 U ___rg_alloc
                 U ___rg_alloc_zeroed
                 U ___rg_dealloc
                 U ___rg_realloc
0000000000000000 T ___rust_alloc
0000000000000030 T ___rust_alloc_zeroed
0000000000000010 T ___rust_dealloc
0000000000000020 T ___rust_realloc]

$  nm xargo/target/debug/deps/xargo-1eae7525e610cc5d.xargo.6g0vpmg5-cgu.0.rcgu.o
0000000000000000 t __ZN12alloc_system16realloc_fallback38_$LT$impl$u20$alloc_system..System$GT$16realloc_fallback17hb26a786c8cba6971E
00000000000000d0 t __ZN12alloc_system8platform14aligned_malloc17hd77223dfc84314d5E
0000000000000140 t __ZN12alloc_system8platform75_$LT$impl$u20$core..alloc..GlobalAlloc$u20$for$u20$alloc_system..System$GT$12alloc_zeroed17h79368c8eb8fc6e8eE
0000000000000280 t __ZN12alloc_system8platform75_$LT$impl$u20$core..alloc..GlobalAlloc$u20$for$u20$alloc_system..System$GT$5alloc17h4ed6afcc55fd971dE
0000000000000360 t __ZN12alloc_system8platform75_$LT$impl$u20$core..alloc..GlobalAlloc$u20$for$u20$alloc_system..System$GT$7dealloc17h1e69e6d3ecea17e7E
0000000000000390 t __ZN12alloc_system8platform75_$LT$impl$u20$core..alloc..GlobalAlloc$u20$for$u20$alloc_system..System$GT$7realloc17he7eabe075503b093E
0000000000000440 t __ZN35_$LT$core..ptr..Unique$LT$T$GT$$GT$6as_ptr17haa43b151e81becb1E
0000000000000460 t __ZN4core3cmp3Ord3min17h564fa61d56e9b034E
00000000000004e0 t __ZN4core3cmp3min17h501037777ab80b60E
0000000000000510 t __ZN4core3cmp5impls57_$LT$impl$u20$core..cmp..PartialOrd$u20$for$u20$usize$GT$2le17hbb5bd3d10381b616E
0000000000000540 t __ZN4core3num12NonZeroUsize13new_unchecked17h167557d6c0d13e16E
0000000000000570 t __ZN4core3num12NonZeroUsize3get17hb43aad1e531da046E
0000000000000590 t __ZN4core3ptr13drop_in_place17hbfa94f7f536f4f1aE
00000000000005c0 t __ZN4core3ptr31_$LT$impl$u20$$BP$mut$u20$T$GT$7is_null17h02f95dcef0263e66E
0000000000000600 t __ZN4core3ptr8null_mut17h152b26580cbcb7dcE
0000000000000610 t __ZN4core3ptr8null_mut17hc429d83742372fa5E
0000000000000620 t __ZN4core5alloc6Layout25from_size_align_unchecked17hf2ead6bf6994c8b9E
0000000000000670 t __ZN4core5alloc6Layout4size17h23d7a6031eeb96edE
0000000000000690 t __ZN4core5alloc6Layout5align17h3dd4ae9cc3d253a4E
00000000000006c0 t __ZN58_$LT$core..alloc..Layout$u20$as$u20$core..clone..Clone$GT$5clone17hd4d1e4021aab0408E
00000000000006e0 t __ZN5alloc5alloc15exchange_malloc17he4ad6b3b3fe9e17dE
0000000000000760 t __ZN5alloc5alloc18handle_alloc_error17h8b7d97331e5aea64E
0000000000000780 t __ZN5alloc5alloc5alloc17h5a1cee734b52541aE
00000000000007d0 t __ZN5alloc5alloc7dealloc17h7f817ec477fb33b0E
0000000000000820 t __ZN5alloc5alloc8box_free17h3b1e85a33b3d2dbcE
00000000000008c0 t __ZN5xargo4main17ha4fe8a15b487d3a2E
0000000000000ab2 s __ZN5xargo5ALLOC17hacdde07616dc6e79E
0000000000000930 T ___rg_alloc
0000000000000a50 T ___rg_alloc_zeroed
0000000000000980 T ___rg_dealloc
00000000000009e0 T ___rg_realloc
                 U ___rust_alloc
                 U ___rust_dealloc
                 U _calloc
                 U _free
0000000000000aa0 T _main
                 U _malloc
                 U _memcpy
                 U _memset
                 U _posix_memalign
                 U _puts
                 U _realloc
0000000000000890 T _rust_begin_unwind
00000000000008a0 T _rust_oom
0000000000000ab3 s l___unnamed_1

[bjorn3]

Got it finally fixed locally!!! Will push it later.

[bjorn3]

Fixed in d67fd16...d20f54b

Please note that it only works on macOS, not linux, because the linker doesn't accept duplicate definitions of a symbol.