CmmBrokenBlock

ghc-7.0.4: The GHC API

CmmBrokenBlock

Synopsis

- data BrokenBlock = BrokenBlock {
  - brokenBlockId :: BlockId
  - brokenBlockEntry :: BlockEntryInfo
  - brokenBlockStmts :: [CmmStmt]
  - brokenBlockTargets :: [BlockId]
  - brokenBlockExit :: FinalStmt
  }
- data BlockEntryInfo
  - = FunctionEntry CmmInfo CLabel CmmFormals
  - | ContinuationEntry CmmFormals C_SRT Bool
  - | ControlEntry
- data FinalStmt
  - = FinalBranch BlockId
  - | FinalReturn HintedCmmActuals
  - | FinalJump CmmExpr HintedCmmActuals
  - | FinalCall BlockId CmmCallTarget HintedCmmFormals HintedCmmActuals C_SRT CmmReturnInfo Bool
  - | FinalSwitch CmmExpr [Maybe BlockId]
- breakBlock :: [BlockId] -> [Unique] -> CmmBasicBlock -> BlockEntryInfo -> ([(BlockId, ContFormat)], [BrokenBlock])
- cmmBlockFromBrokenBlock :: BrokenBlock -> CmmBasicBlock
- blocksToBlockEnv :: [BrokenBlock] -> BlockEnv BrokenBlock
- adaptBlockToFormat :: [(BlockId, ContFormat)] -> Unique -> BrokenBlock -> [BrokenBlock]
- selectContinuations :: [(BlockId, ContFormat)] -> [(BlockId, ContFormat)]
- data ContFormat
- makeContinuationEntries :: [(BlockId, ContFormat)] -> BrokenBlock -> BrokenBlock

# Documentation

data BrokenBlock

Similar to a `CmmBlock` with a little extra information to help the CPS analysis.

Constructors

BrokenBlock |
Fields brokenBlockId :: BlockId The block's label like a `CmmBasicBlock` brokenBlockEntry :: BlockEntryInfo Ways this block can be entered brokenBlockStmts :: [CmmStmt] Body like a CmmBasicBlock (but without the last statement) brokenBlockTargets :: [BlockId] Blocks that this block could branch to either by conditional branches or via the last statement brokenBlockExit :: FinalStmt The final statement of the block

data BlockEntryInfo

How a block could be entered See Note [An example of CPS conversion]

Constructors

FunctionEntry CmmInfo CLabel CmmFormals | Block is the beginning of a function, parameters are: 1. Function header info 2. The function name 3. Aguments to function Only the formal parameters are live
ContinuationEntry CmmFormals C_SRT Bool | Return point of a function call, parameters are: 1. return values (argument to continuation) 2. SRT for the continuation's info table 3. True = GC block so ignore stack size Live variables, other than the return values, are on the stack
ControlEntry | Any other kind of block. Only entered due to control flow.

data FinalStmt

Final statement in a `BlokenBlock`. Constructors and arguments match those in `Cmm`, but are restricted to branches, returns, jumps, calls and switches

Constructors

FinalBranch BlockId | Same as `CmmBranch`. Target must be a ControlEntry
FinalReturn HintedCmmActuals | Same as `CmmReturn`. Parameter is the return values.
FinalJump CmmExpr HintedCmmActuals | Same as `CmmJump`. Parameters: 1. The function to call, 2. Arguments of the call
FinalCall BlockId CmmCallTarget HintedCmmFormals HintedCmmActuals C_SRT CmmReturnInfo Bool | Same as `CmmCallee` followed by `CmmGoto`. Parameters: 1. Target of the `CmmGoto` (must be a `ContinuationEntry`) 2. The function to call 3. Results from call (redundant with ContinuationEntry) 4. Arguments to call 5. SRT for the continuation's info table 6. Does the function return? 7. True = GC block so ignore stack size
FinalSwitch CmmExpr [Maybe BlockId] | Same as a `CmmSwitch`. Paremeters: 1. Scrutinee (zero based) 2. Targets

breakBlock

Arguments

:: [BlockId] | Any GC blocks that should be special
-> [Unique] | An infinite list of uniques to create names of the new blocks with
-> CmmBasicBlock | Input block to break apart
-> BlockEntryInfo | Info for the first created `BrokenBlock`
-> ([(BlockId, ContFormat)], [BrokenBlock]) |

Takes a `CmmBasicBlock` and breaks it up into a list of `BrokenBlock` by splitting on each `CmmCall` in the `CmmBasicBlock`.

cmmBlockFromBrokenBlock :: BrokenBlock -> CmmBasicBlock

Convert from a BrokenBlock back to an equivalent CmmBasicBlock Needed by liveness analysis

blocksToBlockEnv :: [BrokenBlock] -> BlockEnv BrokenBlock

Build a mapping so we can lookup a `BrokenBlock` by its `BlockId`

adaptBlockToFormat :: [(BlockId, ContFormat)] -> Unique -> BrokenBlock -> [BrokenBlock]

selectContinuations :: [(BlockId, ContFormat)] -> [(BlockId, ContFormat)]

data ContFormat

Instances

Eq ContFormat |

makeContinuationEntries :: [(BlockId, ContFormat)] -> BrokenBlock -> BrokenBlock