diff options
| -rw-r--r-- | compiler/GHC/Cmm/Node.hs | 13 | ||||
| -rw-r--r-- | compiler/GHC/Cmm/Sink.hs | 1 | ||||
| -rw-r--r-- | compiler/GHC/StgToCmm/Foreign.hs | 2 | ||||
| -rw-r--r-- | compiler/GHC/StgToCmm/Utils.hs | 2 | ||||
| -rw-r--r-- | includes/stg/MachRegs.h | 2 |
5 files changed, 12 insertions, 8 deletions
diff --git a/compiler/GHC/Cmm/Node.hs b/compiler/GHC/Cmm/Node.hs index 31a3d14a86..01db60b116 100644 --- a/compiler/GHC/Cmm/Node.hs +++ b/compiler/GHC/Cmm/Node.hs @@ -93,7 +93,7 @@ data CmmNode e x where -- -- Invariant: the arguments and the ForeignTarget must not -- mention any registers for which GHC.Platform.callerSaves - -- is True. See Note [Register Parameter Passing]. + -- is True. See Note [Register parameter passing]. CmmBranch :: ULabel -> CmmNode O C -- Goto another block in the same procedure @@ -223,11 +223,12 @@ convention, rdi, rsi, rdx and rcx (as well as r8 and r9) may be used for argument passing. These are registers R3-R6, which our generated code may also be using; as a result, it's necessary to save these values before doing a foreign call. This is done during initial -code generation in callerSaveVolatileRegs in GHC.StgToCmm.Utils. However, -one result of doing this is that the contents of these registers -may mysteriously change if referenced inside the arguments. This -is dangerous, so you'll need to disable inlining much in the same -way is done in GHC.Cmm.Opt currently. We should fix this! +code generation in callerSaveVolatileRegs in GHC.StgToCmm.Utils. + +However, one result of doing this is that the contents of these registers may +mysteriously change if referenced inside the arguments. This is dangerous, so +you'll need to disable inlining much in the same way is done in GHC.Cmm.Sink +currently. We should fix this! -} --------------------------------------------- diff --git a/compiler/GHC/Cmm/Sink.hs b/compiler/GHC/Cmm/Sink.hs index bd8c19d2d3..0d16411de3 100644 --- a/compiler/GHC/Cmm/Sink.hs +++ b/compiler/GHC/Cmm/Sink.hs @@ -772,6 +772,7 @@ regAddr _ _ _ _ = AnyMem {- Note [Inline GlobalRegs?] +~~~~~~~~~~~~~~~~~~~~~~~~~ Should we freely inline GlobalRegs? diff --git a/compiler/GHC/StgToCmm/Foreign.hs b/compiler/GHC/StgToCmm/Foreign.hs index 1f0939d344..ecab35714f 100644 --- a/compiler/GHC/StgToCmm/Foreign.hs +++ b/compiler/GHC/StgToCmm/Foreign.hs @@ -261,7 +261,7 @@ load_target_into_temp other_target@(PrimTarget _) = -- What we want to do here is create a new temporary for the foreign -- call argument if it is not safe to use the expression directly, -- because the expression mentions caller-saves GlobalRegs (see --- Note [Register Parameter Passing]). +-- Note [Register parameter passing]). -- -- However, we can't pattern-match on the expression here, because -- this is used in a loop by GHC.Cmm.Parser, and testing the expression diff --git a/compiler/GHC/StgToCmm/Utils.hs b/compiler/GHC/StgToCmm/Utils.hs index 8531ca2283..f1a68eeb28 100644 --- a/compiler/GHC/StgToCmm/Utils.hs +++ b/compiler/GHC/StgToCmm/Utils.hs @@ -243,7 +243,7 @@ emitRtsCallGen res lbl args safe -- shouldn't be doing the workaround at this point in the pipeline, see -- Note [Register parameter passing] and the ToDo on CmmCall in -- "GHC.Cmm.Node". Right now the workaround is to avoid inlining across --- unsafe foreign calls in rewriteAssignments, but this is strictly +-- unsafe foreign calls in GHC.Cmm.Sink, but this is strictly -- temporary. callerSaveVolatileRegs :: Platform -> (CmmAGraph, CmmAGraph) callerSaveVolatileRegs platform = (caller_save, caller_load) diff --git a/includes/stg/MachRegs.h b/includes/stg/MachRegs.h index 82cce6e66a..be7b7d60b4 100644 --- a/includes/stg/MachRegs.h +++ b/includes/stg/MachRegs.h @@ -61,6 +61,8 @@ are the RX, FX, DX and USER registers; as a result, if you decide to caller save a system register (e.g. SP, HP, etc), note that this code path is completely untested! -- EZY + + See Note [Register parameter passing] for details. -------------------------------------------------------------------------- */ /* ----------------------------------------------------------------------------- |