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Diffstat (limited to 'docs/LangRef.rst')
| -rw-r--r-- | docs/LangRef.rst | 34 |
1 files changed, 31 insertions, 3 deletions
diff --git a/docs/LangRef.rst b/docs/LangRef.rst index 68aa500150ae3..2a0812ab930fb 100644 --- a/docs/LangRef.rst +++ b/docs/LangRef.rst @@ -1468,6 +1468,19 @@ example: This attribute by itself does not imply restrictions on inter-procedural optimizations. All of the semantic effects the patching may have to be separately conveyed via the linkage type. +``"probe-stack"`` + This attribute indicates that the function will trigger a guard region + in the end of the stack. It ensures that accesses to the stack must be + no further apart than the size of the guard region to a previous + access of the stack. It takes one required string value, the name of + the stack probing function that will be called. + + If a function that has a ``"probe-stack"`` attribute is inlined into + a function with another ``"probe-stack"`` attribute, the resulting + function has the ``"probe-stack"`` attribute of the caller. If a + function that has a ``"probe-stack"`` attribute is inlined into a + function that has no ``"probe-stack"`` attribute at all, the resulting + function has the ``"probe-stack"`` attribute of the callee. ``readnone`` On a function, this attribute indicates that the function computes its result (or decides to unwind an exception) based strictly on its arguments, @@ -1498,6 +1511,21 @@ example: On an argument, this attribute indicates that the function does not write through this pointer argument, even though it may write to the memory that the pointer points to. +``"stack-probe-size"`` + This attribute controls the behavior of stack probes: either + the ``"probe-stack"`` attribute, or ABI-required stack probes, if any. + It defines the size of the guard region. It ensures that if the function + may use more stack space than the size of the guard region, stack probing + sequence will be emitted. It takes one required integer value, which + is 4096 by default. + + If a function that has a ``"stack-probe-size"`` attribute is inlined into + a function with another ``"stack-probe-size"`` attribute, the resulting + function has the ``"stack-probe-size"`` attribute that has the lower + numeric value. If a function that has a ``"stack-probe-size"`` attribute is + inlined into a function that has no ``"stack-probe-size"`` attribute + at all, the resulting function has the ``"stack-probe-size"`` attribute + of the callee. ``writeonly`` On a function, this attribute indicates that the function may write to but does not read from memory. @@ -1989,7 +2017,7 @@ A pointer value is *based* on another pointer value according to the following rules: - A pointer value formed from a ``getelementptr`` operation is *based* - on the first value operand of the ``getelementptr``. + on the second value operand of the ``getelementptr``. - The result value of a ``bitcast`` is *based* on the operand of the ``bitcast``. - A pointer value formed by an ``inttoptr`` is *based* on all pointer @@ -3166,7 +3194,7 @@ The following is the syntax for constant expressions: ``getelementptr (TY, CSTPTR, IDX0, IDX1, ...)``, ``getelementptr inbounds (TY, CSTPTR, IDX0, IDX1, ...)`` Perform the :ref:`getelementptr operation <i_getelementptr>` on constants. As with the :ref:`getelementptr <i_getelementptr>` - instruction, the index list may have zero or more indexes, which are + instruction, the index list may have one or more indexes, which are required to make sense for the type of "pointer to TY". ``select (COND, VAL1, VAL2)`` Perform the :ref:`select operation <i_select>` on constants. @@ -7805,7 +7833,7 @@ base address to start from. The remaining arguments are indices that indicate which of the elements of the aggregate object are indexed. The interpretation of each index is dependent on the type being indexed into. The first index always indexes the pointer value given as the -first argument, the second index indexes a value of the type pointed to +second argument, the second index indexes a value of the type pointed to (not necessarily the value directly pointed to, since the first index can be non-zero), etc. The first type indexed into must be a pointer value, subsequent types can be arrays, vectors, and structs. Note that |