diff options
| author | Erik de Castro Lopo <erikd@mega-nerd.com> | 2015-10-11 16:48:11 +1100 |
|---|---|---|
| committer | Erik de Castro Lopo <erikd@mega-nerd.com> | 2015-10-15 09:19:35 +1100 |
| commit | 933adc0f31164cb651d11ecfcfe612ac429f714f (patch) | |
| tree | c49a8c05daee1987e93b30e36cda22609aefbdeb /compiler | |
| parent | 775616174bf297c7f3d8dc35ae0e88aef381f7fa (diff) | |
| download | haskell-933adc0f31164cb651d11ecfcfe612ac429f714f.tar.gz | |
Fix GHCi on Arm (#10375).
Arm has two instruction sets, Arm and Thumb, and an execution mode for each.
Executing Arm code in Thumb mode or vice-versa will likely result in an
Illegal instruction exception.
Furthermore, Haskell code compiled via LLVM was generating Arm instructions
while C code compiled via GCC was generating Thumb code by default. When
these two object code types were being linked by the system linker, all was
fine, because the system linker knows how to jump and call from one
instruction set to the other.
The first problem was with GHCi's object code loader which did not know
about Thumb vs Arm. When loading an object file `StgCRun` would jump
into the loaded object which could change the mode causing a crash after
it returned. This was fixed by forcing all C code to generate Arm
instructions by passing `-marm` to GCC.
The second problem was the `mkJumpToAddr` function which was generating
Thumb instructions. Changing that to generate Arm instructions instead
results in a working GHCi on Arm.
Test Plan: validate on x86_64 and arm
Reviewers: bgamari, austin, hvr
Subscribers: thomie
Differential Revision: https://phabricator.haskell.org/D1323
GHC Trac Issues: #10375
Diffstat (limited to 'compiler')
| -rw-r--r-- | compiler/ghci/ByteCodeItbls.hs | 10 | ||||
| -rw-r--r-- | compiler/llvmGen/LlvmCodeGen/Ppr.hs | 2 |
2 files changed, 6 insertions, 6 deletions
diff --git a/compiler/ghci/ByteCodeItbls.hs b/compiler/ghci/ByteCodeItbls.hs index cd31acb7b6..a01fcd89b9 100644 --- a/compiler/ghci/ByteCodeItbls.hs +++ b/compiler/ghci/ByteCodeItbls.hs @@ -219,17 +219,17 @@ mkJumpToAddr dflags a = case platformArch (targetPlatform dflags) of , fromIntegral ((w64 `shiftR` 32) .&. 0x0000FFFF) ] ArchARM { } -> - -- Generates Thumb sequence, + -- Generates Arm sequence, -- ldr r1, [pc, #0] -- bx r1 -- -- which looks like: -- 00000000 <.addr-0x8>: - -- 0: 4900 ldr r1, [pc] ; 8 <.addr> - -- 4: 4708 bx r1 + -- 0: 00109fe5 ldr r1, [pc] ; 8 <.addr> + -- 4: 11ff2fe1 bx r1 let w32 = fromIntegral (funPtrToInt a) :: Word32 - in Left [ 0x49, 0x00 - , 0x47, 0x08 + in Left [ 0x00, 0x10, 0x9f, 0xe5 + , 0x11, 0xff, 0x2f, 0xe1 , byte0 w32, byte1 w32, byte2 w32, byte3 w32] arch -> diff --git a/compiler/llvmGen/LlvmCodeGen/Ppr.hs b/compiler/llvmGen/LlvmCodeGen/Ppr.hs index 1a9373bce2..d7ddf804f2 100644 --- a/compiler/llvmGen/LlvmCodeGen/Ppr.hs +++ b/compiler/llvmGen/LlvmCodeGen/Ppr.hs @@ -52,7 +52,7 @@ moduleLayout = sdocWithPlatform $ \platform -> $+$ text "target triple = \"x86_64-linux-gnu\"" Platform { platformArch = ArchARM {}, platformOS = OSLinux } -> text "target datalayout = \"e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:64:128-a0:0:64-n32\"" - $+$ text "target triple = \"arm-unknown-linux-gnueabi\"" + $+$ text "target triple = \"armv6-unknown-linux-gnueabihf\"" Platform { platformArch = ArchARM {}, platformOS = OSAndroid } -> text "target datalayout = \"e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:64:128-a0:0:64-n32\"" $+$ text "target triple = \"arm-unknown-linux-androideabi\"" |