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Module `dmd.escape`

Most of the logic to implement scoped pointers and scoped references is here.

Documentation

https://dlang.org/phobos/dmd_escape.html

Coverage

https://codecov.io/gh/dlang/dmd/src/master/src/dmd/escape.d

Functions

Name	Description
`checkArrayLiteralEscape(sc, ae, gag)`	Array literal is going to be allocated on the GC heap. Check its elements to see if any would escape by going on the heap.
`checkAssignEscape(sc, e, gag, byRef)`	Given an `AssignExp`, determine if the lvalue will cause the contents of the rvalue to escape. Print error messages when these are detected. Infer `scope` attribute for the lvalue where possible, in order to eliminate the error.
`checkAssocArrayLiteralEscape(sc, ae, gag)`	Associative array literal is going to be allocated on the GC heap. Check its elements to see if any would escape by going on the heap.
`checkConstructorEscape(sc, ce, gag)`	Check struct constructor of the form `s.this(args)`, by checking each `return` parameter to see if it gets assigned to `s`.
`checkMutableArguments(sc, fd, tf, ethis, arguments, gag)`	Checks memory objects passed to a function. Checks that if a memory object is passed by ref or by pointer, all of the refs or pointers are const, or there is only one mutable ref or pointer to it.
`checkNewEscape(sc, e, gag)`	Detect cases where pointers to the stack can escape the lifetime of the stack frame by being placed into a GC allocated object. Print error messages when these are detected.
`checkParamArgumentEscape(sc, fdc, par, arg, assertmsg, gag)`	Function parameter `par` is being initialized to `arg`, and `par` may escape. Detect if scoped values can escape this way. Print error messages when these are detected.
`checkParamArgumentReturn(sc, firstArg, arg, param, gag)`	Function argument initializes a `return` parameter, and that parameter gets assigned to `firstArg`. Essentially, treat as `firstArg = arg;`
`checkReturnEscape(sc, e, gag)`	Detect cases where pointers to the stack can escape the lifetime of the stack frame by returning `e` by value. Print error messages when these are detected.
`checkReturnEscapeRef(sc, e, gag)`	Detect cases where returning `e` by `ref` can result in a reference to the stack being returned. Print error messages when these are detected.
`checkThrowEscape(sc, e, gag)`	Detect cases where pointers to the stack can escape the lifetime of the stack frame when throwing `e`. Print error messages when these are detected.
`eliminateMaybeScopes(array)`	Have some variables that are maybescopes that were assigned values from other maybescope variables. Now that semantic analysis of the function is complete, we can finalize this by turning off maybescope for array elements that cannot be scope.
`escapeByRef(e, er, live)`	e is an expression to be returned by 'ref'. Walk e to determine which variables are possibly being returned by ref, such as: ref int function(int i) { return i; } If e is a form of p, determine which variables have content which is being returned as ref, such as: ref int function(int p) { return p; } Multiple variables can be inserted, because of expressions like this: ref int function(bool b, int i, int p) { return b ? i : *p; }
`escapeByValue(e, er, live)`	e is an expression to be returned by value, and that value contains pointers. Walk e to determine which variables are possibly being returned by value, such as: int* function(int* p) { return p; } If e is a form of &p, determine which variables have content which is being returned as ref, such as: int* function(int i) { return &i; } Multiple variables can be inserted, because of expressions like this: int function(bool b, int i, int* p) { return b ? &i : p; }
`findAllOuterAccessedVariables(fd, vars)`	Find all variables accessed by this delegate that are in functions enclosing it.
`isReferenceToMutable(t)`	Is type a reference to a mutable value?
`isReferenceToMutable(p, t)`	Is parameter a reference to a mutable value?
`notMaybeScope(v)`	Turn off `STC.maybescope` for variable `v`.

Structs

Name	Description
`EscapeByResults`	Aggregate the data collected by the escapeBy??() functions.

Authors

Walter Bright

License

Boost License 1.0