dmd.ob

void oblive(FuncDeclaration funcdecl);

Perform ownership/borrowing checks for funcdecl. Does not modify the AST, just checks for errors.

struct ObState;

Collect the state information.

Array!size_t varStack;

temporary storage

Array!bool mutableStack;

parallel to varStack[], is type mutable?

PtrVarState[] varPool;

memory pool

struct ObNode;

A node in the function's expression graph, and its edges to predecessors and successors.

Expression exp;

expression for the node

ObNodes preds;

predecessors

ObNodes succs;

successors

ObNode* tryBlock;

try-finally block we're inside

uint index;

index of this in obnodes

PtrVarState[] gen;

new states generated for this node

PtrVarState[] input;

variable states on entry to exp

PtrVarState[] output;

variable states on exit to exp

enum PtrState: ubyte;

Pointer variable states:

Initial state is not known; ignore for now

Undefined not in a usable state

T* p = void;

Owner mutable pointer

T* p = initializer;

Borrowed scope mutable pointer, borrowed from [p]

T* p = initializer; scope T* b = p;

Readonly scope const pointer, copied from [p]

T* p = initializer; scope const(T)* cp = p;

Examples:

T* p = initializer; // p is owner T** pp = &p; // pp borrows from p

T* p = initialize; // p is owner T* q = p; // transfer: q is owner, p is undefined

const(char)* PtrStateToChars(PtrState state);

struct PtrVarState;

Carries the state of a pointer variable.

BitArray deps;

dependencies

PtrState state;

state the pointer variable is in

void print(VarDeclaration[] vars);

void depsToBuf(ref OutBuffer buf, const VarDeclaration[] vars);

Produce a user-readable comma separated string of the dependencies.

Parameters:

OutBuffer buf	write resulting string here
VarDeclaration[] vars	array from which to get the variable names

void setLabelStatementExtraFields(DsymbolTable labtab);

Set the .extra field for LabelStatements in labtab[].

void toObNodes(ref ObNodes obnodes, Statement s);

Convert statement into ObNodes.

void insertFinallyBlockCalls(ref ObNodes obnodes);

Insert finally block calls when doing a goto from inside a try block to outside. Done after blocks are generated because then we know all the edges of the graph, but before the pred's are computed.

Parameters:

ObNodes obnodes

graph of the function

void insertFinallyBlockGotos(ref ObNodes obnodes);

Remove try-finally scaffolding.

Parameters:

ObNodes obnodes

nodes for the function

@safe void numberNodes(ref ObNodes obnodes);

Set the index field of each ObNode to its index in the obnodes[] array.

void removeUnreachable(ref ObNodes obnodes);

Remove unreachable nodes and compress them out of obnodes[].

Parameters:

ObNodes obnodes

array of nodes

void computePreds(ref ObNodes obnodes);

Compute predecessors.

bool isTrackableVar(VarDeclaration v);

Are we interested in tracking variable v?

VarDeclaration isTrackableVarExp(Expression e);

Are we interested in tracking this expression?

Returns:

variable if so, null if not

void collectVars(FuncDeclaration funcdecl, out VarDeclarations vars);

Find the pointer variable declarations in this function, and fill vars with them.

Parameters:

FuncDeclaration funcdecl	function we are in
VarDeclarations vars	array to fill in

void allocDeps(PtrVarState[] pvss);

Allocate BitArrays in PtrVarState. Can be allocated much more efficiently by subdividing a single large array of bits

void allocStates(ref ObState obstate);

Allocate state variables foreach node.

bool isBorrowedPtr(VarDeclaration v);

Does v meet the definiton of a Borrowed pointer?

Returns:

true if it does

bool isReadonlyPtr(VarDeclaration v);

Does v meet the definiton of a Readonly pointer?

Returns:

true if it does

void genKill(ref ObState obstate, ObNode* ob);

Compute the gen vector for ob.

PtrState toPtrState(VarDeclaration v);

Determine the state of a variable based on its type and storage class.

bool hasPointersToMutableFields(Type t);

Does type t contain any pointers to mutable?

bool hasMutableFields(Type t);

Does type t have any mutable fields?

void doDataFlowAnalysis(ref ObState obstate);

Do the data flow analysis (i.e. compute the input[] and output[] vectors for each ObNode).

void checkObErrors(ref ObState obstate);

Check for Ownership/Borrowing errors.

void readVar(ObNode* ob, const size_t vi, bool mutable, PtrVarState[] gen);

Read from variable vi. The beginning of the 'scope' of a variable is when it is first read. Hence, when a read is done, instead of when assignment to the variable is done, the O/B rules are enforced. (Also called "non-lexical scoping".)

void makeChildrenUndefined(size_t vi, PtrVarState[] gen);

Recursively make Undefined all who list vi as a dependency

void makeUndefined(size_t vi, PtrVarState[] gen);

Recursively make Undefined vi undefined and all who list vi as a dependency

bool isMutableRef(Type t);

Is type t a reference to a const or a reference to a mutable?