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Diffstat (limited to 'llvm/docs/LangRef.rst')
| -rw-r--r-- | llvm/docs/LangRef.rst | 72 |
1 files changed, 60 insertions, 12 deletions
diff --git a/llvm/docs/LangRef.rst b/llvm/docs/LangRef.rst index 3a3a74f..99a0b17 100644 --- a/llvm/docs/LangRef.rst +++ b/llvm/docs/LangRef.rst @@ -5175,6 +5175,8 @@ The following is the syntax for constant expressions: Perform the :ref:`trunc operation <i_trunc>` on constants. ``ptrtoint (CST to TYPE)`` Perform the :ref:`ptrtoint operation <i_ptrtoint>` on constants. +``ptrtoaddr (CST to TYPE)`` + Perform the :ref:`ptrtoaddr operation <i_ptrtoaddr>` on constants. ``inttoptr (CST to TYPE)`` Perform the :ref:`inttoptr operation <i_inttoptr>` on constants. This one is *really* dangerous! @@ -12523,6 +12525,58 @@ Example: %Y = ptrtoint ptr %P to i64 ; yields zero extension on 32-bit architecture %Z = ptrtoint <4 x ptr> %P to <4 x i64>; yields vector zero extension for a vector of addresses on 32-bit architecture +.. _i_ptrtoaddr: + +'``ptrtoaddr .. to``' Instruction +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +Syntax: +""""""" + +:: + + <result> = ptrtoaddr <ty> <value> to <ty2> ; yields ty2 + +Overview: +""""""""" + +The '``ptrtoaddr``' instruction converts the pointer or a vector of +pointers ``value`` to the underlying integer address (or vector of addresses) of +type ``ty2``. This is different from :ref:`ptrtoint <i_ptrtoint>` in that it +only operates on the index bits of the pointer and ignores all other bits, and +does not capture the provenance of the pointer. + +Arguments: +"""""""""" + +The '``ptrtoaddr``' instruction takes a ``value`` to cast, which must be +a value of type :ref:`pointer <t_pointer>` or a vector of pointers, and a +type to cast it to ``ty2``, which must be must be the :ref:`integer <t_integer>` +type (or vector of integers) matching the pointer index width of the address +space of ``ty``. + +Semantics: +"""""""""" + +The '``ptrtoaddr``' instruction converts ``value`` to integer type ``ty2`` by +interpreting the lowest index-width pointer representation bits as an integer. +If the address size and the pointer representation size are the same and +``value`` and ``ty2`` are the same size, then nothing is done (*no-op cast*) +other than a type change. + +The ``ptrtoaddr`` instruction always :ref:`captures the address but not the provenance <pointercapture>` +of the pointer argument. + +Example: +"""""""" +This example assumes pointers in address space 1 are 64 bits in size with an +address width of 32 bits (``p1:64:64:64:32`` :ref:`datalayout string<langref_datalayout>`) +.. code-block:: llvm + + %X = ptrtoaddr ptr addrspace(1) %P to i32 ; extracts low 32 bits of pointer + %Y = ptrtoaddr <4 x ptr addrspace(1)> %P to <4 x i32>; yields vector of low 32 bits for each pointer + + .. _i_inttoptr: '``inttoptr .. to``' Instruction @@ -26730,7 +26784,7 @@ Syntax: :: - declare void @llvm.lifetime.start(i64 <size>, ptr captures(none) <ptr>) + declare void @llvm.lifetime.start(ptr captures(none) <ptr>) Overview: """"""""" @@ -26741,11 +26795,8 @@ object's lifetime. Arguments: """""""""" -The first argument is a constant integer, which is ignored and will be removed -in the future. - -The second argument is either a pointer to an ``alloca`` instruction or -a ``poison`` value. +The argument is either a pointer to an ``alloca`` instruction or a ``poison`` +value. Semantics: """""""""" @@ -26774,7 +26825,7 @@ Syntax: :: - declare void @llvm.lifetime.end(i64 <size>, ptr captures(none) <ptr>) + declare void @llvm.lifetime.end(ptr captures(none) <ptr>) Overview: """"""""" @@ -26785,11 +26836,8 @@ The '``llvm.lifetime.end``' intrinsic specifies the end of a Arguments: """""""""" -The first argument is a constant integer, which is ignored and will be removed -in the future. - -The second argument is either a pointer to an ``alloca`` instruction or -a ``poison`` value. +The argument is either a pointer to an ``alloca`` instruction or a ``poison`` +value. Semantics: """""""""" |