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docs: Update LangRef and SourceLevelDebugging
Cleanup some bitrot in SourceLevelDebugging.rst.
- Pull the still-relevant details about individual descriptors into
LangRef.rst. Cut a lot of it to avoid over-describing the fields,
as the C++ classes and assembly format are mostly self-describing
now. If there's anything specific that I shouldn't have cut, let me
know and I'll add it back.
- Rewrite the remaining sections to refer to the new debug info
hierarchy in LangRef.rst.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232566 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Duncan P. N. Exon Smith
parent
5e15d64948
commit
89064930a0
107
docs/LangRef.rst
107
docs/LangRef.rst
@ -2897,6 +2897,8 @@ attached to the ``add`` instruction using the ``!dbg`` identifier:
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More information about specific metadata nodes recognized by the
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optimizers and code generator is found below.
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.. _specialized-metadata:
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Specialized Metadata Nodes
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^^^^^^^^^^^^^^^^^^^^^^^^^^
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@ -2907,6 +2909,8 @@ order.
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These aren't inherently debug info centric, but currently all the specialized
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metadata nodes are related to debug info.
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.. _MDCompileUnit:
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MDCompileUnit
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"""""""""""""
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@ -2924,6 +2928,14 @@ references to them from instructions).
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enums: !2, retainedTypes: !3, subprograms: !4,
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globals: !5, imports: !6)
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Compile unit descriptors provide the root scope for objects declared in a
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specific compilation unit. File descriptors are defined using this scope.
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These descriptors are collected by a named metadata ``!llvm.dbg.cu``. They
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keep track of subprograms, global variables, type information, and imported
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entities (declarations and namespaces).
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.. _MDFile:
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MDFile
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""""""
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@ -2933,13 +2945,16 @@ MDFile
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!0 = !MDFile(filename: "path/to/file", directory: "/path/to/dir")
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Files are sometimes used in ``scope:`` fields, and are the only valid target
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for ``file:`` fields.
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.. _MDLocation:
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MDBasicType
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"""""""""""
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``MDBasicType`` nodes represent primitive types. ``tag:`` defaults to
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``DW_TAG_base_type``.
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``MDBasicType`` nodes represent primitive types, such as ``int``, ``bool`` and
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``float``. ``tag:`` defaults to ``DW_TAG_base_type``.
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.. code-block:: llvm
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@ -2947,6 +2962,19 @@ MDBasicType
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encoding: DW_ATE_unsigned_char)
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!1 = !MDBasicType(tag: DW_TAG_unspecified_type, name: "decltype(nullptr)")
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The ``encoding:`` describes the details of the type. Usually it's one of the
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following:
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.. code-block:: llvm
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DW_ATE_address = 1
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DW_ATE_boolean = 2
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DW_ATE_float = 4
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DW_ATE_signed = 5
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DW_ATE_signed_char = 6
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DW_ATE_unsigned = 7
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DW_ATE_unsigned_char = 8
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.. _MDSubroutineType:
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MDSubroutineType
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@ -2963,6 +2991,8 @@ represents a function with no return value (such as ``void foo() {}`` in C++).
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!1 = !BasicType(name: "char", size: 8, align: 8, DW_ATE_signed_char)
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!2 = !MDSubroutineType(types: !{null, !0, !1}) ; void (int, char)
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.. _MDDerivedType:
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MDDerivedType
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"""""""""""""
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@ -2976,6 +3006,34 @@ qualified types.
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!1 = !MDDerivedType(tag: DW_TAG_pointer_type, baseType: !0, size: 32,
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align: 32)
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The following ``tag:`` values are valid:
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.. code-block:: llvm
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DW_TAG_formal_parameter = 5
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DW_TAG_member = 13
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DW_TAG_pointer_type = 15
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DW_TAG_reference_type = 16
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DW_TAG_typedef = 22
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DW_TAG_ptr_to_member_type = 31
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DW_TAG_const_type = 38
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DW_TAG_volatile_type = 53
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DW_TAG_restrict_type = 55
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``DW_TAG_member`` is used to define a member of a :ref:`composite type
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<MDCompositeType>` or :ref:`subprogram <MDSubprogram>`. The type of the member
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is the ``baseType:``. The ``offset:`` is the member's bit offset.
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``DW_TAG_formal_parameter`` is used to define a member which is a formal
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argument of a subprogram.
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``DW_TAG_typedef`` is used to provide a name for the ``baseType:``.
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``DW_TAG_pointer_type``, ``DW_TAG_reference_type``, ``DW_TAG_const_type``,
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``DW_TAG_volatile_type`` and ``DW_TAG_restrict_type`` are used to qualify the
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``baseType:``.
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Note that the ``void *`` type is expressed as a type derived from NULL.
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.. _MDCompositeType:
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MDCompositeType
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@ -2998,6 +3056,35 @@ can refer to composite types indirectly via a :ref:`metadata string
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line: 2, size: 32, align: 32, identifier: "_M4Enum",
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elements: !{!0, !1, !2})
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The following ``tag:`` values are valid:
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.. code-block:: llvm
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DW_TAG_array_type = 1
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DW_TAG_class_type = 2
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DW_TAG_enumeration_type = 4
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DW_TAG_structure_type = 19
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DW_TAG_union_type = 23
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DW_TAG_subroutine_type = 21
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DW_TAG_inheritance = 28
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For ``DW_TAG_array_type``, the ``elements:`` should be :ref:`subrange
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descriptors <MDSubrange>`, each representing the range of subscripts at that
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level of indexing. The ``DIFlagVector`` flag to ``flags:`` indicates that an
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array type is a native packed vector.
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For ``DW_TAG_enumeration_type``, the ``elements:`` should be :ref:`enumerator
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descriptors <MDEnumerator>`, each representing the definition of an enumeration
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value for the set. All enumeration type descriptors are collected in the
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``enums:`` field of the :ref:`compile unit <MDCompileUnit>`.
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For ``DW_TAG_structure_type``, ``DW_TAG_class_type``, and
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``DW_TAG_union_type``, the ``elements:`` should be :ref:`derived types
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<MDDerivedType>` with ``tag: DW_TAG_member`` or ``tag: DW_TAG_inheritance``.
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.. _MDSubrange:
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MDSubrange
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""""""""""
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@ -3010,6 +3097,8 @@ MDSubrange
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!1 = !MDSubrange(count: 5, lowerBound: 1) ; array counting from 1
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!2 = !MDSubrange(count: -1) ; empty array.
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.. _MDEnumerator:
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MDEnumerator
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""""""""""""
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@ -3067,6 +3156,9 @@ MDGlobalVariable
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isDefinition: false, variable: i32* @foo,
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declaration: !4)
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All global variables should be referenced by the `globals:` field of a
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:ref:`compile unit <MDCompileUnit>`.
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.. _MDSubprogram:
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MDSubprogram
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@ -3092,12 +3184,17 @@ retained, even if their IR counterparts are optimized out of the IR. The
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MDLexicalBlock
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""""""""""""""
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``MDLexicalBlock`` nodes represent lexical blocks in the source language (a
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scope).
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``MDLexicalBlock`` nodes describe nested blocks within a :ref:`subprogram
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<MDSubprogram>`. The line number and column numbers are used to dinstinguish
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two lexical blocks at same depth. They are valid targets for ``scope:``
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fields.
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.. code-block:: llvm
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!0 = !MDLexicalBlock(scope: !1, file: !2, line: 7, column: 35)
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!0 = distinct !MDLexicalBlock(scope: !1, file: !2, line: 7, column: 35)
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Usually lexical blocks are ``distinct`` to prevent node merging based on
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operands.
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.. _MDLexicalBlockFile:
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@ -153,487 +153,21 @@ debugger to interpret the information.
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To provide basic functionality, the LLVM debugger does have to make some
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assumptions about the source-level language being debugged, though it keeps
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these to a minimum. The only common features that the LLVM debugger assumes
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exist are :ref:`source files <format_files>`, and :ref:`program objects
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<format_global_variables>`. These abstract objects are used by a debugger to
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form stack traces, show information about local variables, etc.
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exist are `source files <LangRef.html#MDFile>`_, and `program objects
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<LangRef.html#MDGlobalVariable>`_. These abstract objects are used by a
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debugger to form stack traces, show information about local variables, etc.
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This section of the documentation first describes the representation aspects
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common to any source-language. :ref:`ccxx_frontend` describes the data layout
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conventions used by the C and C++ front-ends.
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Debug information descriptors
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-----------------------------
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In consideration of the complexity and volume of debug information, LLVM
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provides a specification for well formed debug descriptors.
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Consumers of LLVM debug information expect the descriptors for program objects
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to start in a canonical format, but the descriptors can include additional
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information appended at the end that is source-language specific. All debugging
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information objects start with a tag to indicate what type of object it is.
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The source-language is allowed to define its own objects, by using unreserved
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tag numbers. We recommend using with tags in the range 0x1000 through 0x2000
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(there is a defined ``enum DW_TAG_user_base = 0x1000``.)
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The fields of debug descriptors used internally by LLVM are restricted to only
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the simple data types ``i32``, ``i1``, ``float``, ``double``, ``mdstring`` and
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``mdnode``.
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.. code-block:: llvm
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!1 = metadata !{
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i32, ;; A tag
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...
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}
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Most of the string and integer fields in descriptors are packed into a single,
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null-separated ``mdstring``. The first field of the header is always an
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``i32`` containing the DWARF tag value identifying the content of the
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descriptor.
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For clarity of definition in this document, these header fields are described
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below split inside an imaginary ``DIHeader`` construct. This is invalid
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assembly syntax. In valid IR, these fields are stringified and concatenated,
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separated by ``\00``.
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The details of the various descriptors follow.
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Compile unit descriptors
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^^^^^^^^^^^^^^^^^^^^^^^^
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.. code-block:: llvm
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!0 = metadata !{
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DIHeader(
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i32, ;; Tag = 17 (DW_TAG_compile_unit)
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i32, ;; DWARF language identifier (ex. DW_LANG_C89)
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mdstring, ;; Producer (ex. "4.0.1 LLVM (LLVM research group)")
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i1, ;; True if this is optimized.
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mdstring, ;; Flags
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i32, ;; Runtime version
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mdstring, ;; Split debug filename
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i32 ;; Debug info emission kind (1 = Full Debug Info, 2 = Line Tables Only)
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),
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metadata, ;; Source directory (including trailing slash) & file pair
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metadata, ;; List of enums types
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metadata, ;; List of retained types
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metadata, ;; List of subprograms
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metadata, ;; List of global variables
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metadata ;; List of imported entities
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}
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These descriptors contain a source language ID for the file (we use the DWARF
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3.0 ID numbers, such as ``DW_LANG_C89``, ``DW_LANG_C_plus_plus``,
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``DW_LANG_Cobol74``, etc), a reference to a metadata node containing a pair of
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strings for the source file name and the working directory, as well as an
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identifier string for the compiler that produced it.
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Compile unit descriptors provide the root context for objects declared in a
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specific compilation unit. File descriptors are defined using this context.
|
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These descriptors are collected by a named metadata ``!llvm.dbg.cu``. They
|
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keep track of subprograms, global variables, type information, and imported
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entities (declarations and namespaces).
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.. _format_files:
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File descriptors
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^^^^^^^^^^^^^^^^
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.. code-block:: llvm
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!0 = metadata !{
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DIHeader(
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i32 ;; Tag = 41 (DW_TAG_file_type)
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),
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metadata ;; Source directory (including trailing slash) & file pair
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}
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These descriptors contain information for a file. Global variables and top
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||||
level functions would be defined using this context. File descriptors also
|
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provide context for source line correspondence.
|
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|
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Each input file is encoded as a separate file descriptor in LLVM debugging
|
||||
information output.
|
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|
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.. _format_global_variables:
|
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|
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Global variable descriptors
|
||||
^^^^^^^^^^^^^^^^^^^^^^^^^^^
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|
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.. code-block:: llvm
|
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|
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!1 = metadata !{
|
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DIHeader(
|
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i32, ;; Tag = 52 (DW_TAG_variable)
|
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mdstring, ;; Name
|
||||
mdstring, ;; Display name (fully qualified C++ name)
|
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mdstring, ;; MIPS linkage name (for C++)
|
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i32, ;; Line number where defined
|
||||
i1, ;; True if the global is local to compile unit (static)
|
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i1 ;; True if the global is defined in the compile unit (not extern)
|
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),
|
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metadata, ;; Reference to context descriptor
|
||||
metadata, ;; Reference to file where defined
|
||||
metadata, ;; Reference to type descriptor
|
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{}*, ;; Reference to the global variable
|
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metadata, ;; The static member declaration, if any
|
||||
}
|
||||
|
||||
These descriptors provide debug information about global variables. They
|
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provide details such as name, type and where the variable is defined. All
|
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global variables are collected inside the named metadata ``!llvm.dbg.cu``.
|
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|
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.. _format_subprograms:
|
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|
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Subprogram descriptors
|
||||
^^^^^^^^^^^^^^^^^^^^^^
|
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|
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.. code-block:: llvm
|
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|
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!2 = metadata !{
|
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DIHeader(
|
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i32, ;; Tag = 46 (DW_TAG_subprogram)
|
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mdstring, ;; Name
|
||||
mdstring, ;; Display name (fully qualified C++ name)
|
||||
mdstring, ;; MIPS linkage name (for C++)
|
||||
i32, ;; Line number where defined
|
||||
i1, ;; True if the global is local to compile unit (static)
|
||||
i1, ;; True if the global is defined in the compile unit (not extern)
|
||||
i32, ;; Virtuality, e.g. dwarf::DW_VIRTUALITY__virtual
|
||||
i32, ;; Index into a virtual function
|
||||
i32, ;; Flags - Artificial, Private, Protected, Explicit, Prototyped.
|
||||
i1, ;; isOptimized
|
||||
i32 ;; Line number where the scope of the subprogram begins
|
||||
),
|
||||
metadata, ;; Source directory (including trailing slash) & file pair
|
||||
metadata, ;; Reference to context descriptor
|
||||
metadata, ;; Reference to type descriptor
|
||||
metadata, ;; indicates which base type contains the vtable pointer for the
|
||||
;; derived class
|
||||
{}*, ;; Reference to the LLVM function
|
||||
metadata, ;; Lists function template parameters
|
||||
metadata, ;; Function declaration descriptor
|
||||
metadata ;; List of function variables
|
||||
}
|
||||
|
||||
These descriptors provide debug information about functions, methods and
|
||||
subprograms. They provide details such as name, return types and the source
|
||||
location where the subprogram is defined.
|
||||
|
||||
Block descriptors
|
||||
^^^^^^^^^^^^^^^^^
|
||||
|
||||
.. code-block:: llvm
|
||||
|
||||
!3 = metadata !{
|
||||
DIHeader(
|
||||
i32, ;; Tag = 11 (DW_TAG_lexical_block)
|
||||
i32, ;; Line number
|
||||
i32, ;; Column number
|
||||
i32 ;; Unique ID to identify blocks from a template function
|
||||
),
|
||||
metadata, ;; Source directory (including trailing slash) & file pair
|
||||
metadata ;; Reference to context descriptor
|
||||
}
|
||||
|
||||
This descriptor provides debug information about nested blocks within a
|
||||
subprogram. The line number and column numbers are used to dinstinguish two
|
||||
lexical blocks at same depth.
|
||||
|
||||
.. code-block:: llvm
|
||||
|
||||
!3 = metadata !{
|
||||
DIHeader(
|
||||
i32, ;; Tag = 11 (DW_TAG_lexical_block)
|
||||
i32 ;; DWARF path discriminator value
|
||||
),
|
||||
metadata, ;; Source directory (including trailing slash) & file pair
|
||||
metadata ;; Reference to the scope we're annotating with a file change
|
||||
}
|
||||
|
||||
This descriptor provides a wrapper around a lexical scope to handle file
|
||||
changes in the middle of a lexical block.
|
||||
|
||||
.. _format_basic_type:
|
||||
|
||||
Basic type descriptors
|
||||
^^^^^^^^^^^^^^^^^^^^^^
|
||||
|
||||
.. code-block:: llvm
|
||||
|
||||
!4 = metadata !{
|
||||
DIHeader(
|
||||
i32, ;; Tag = 36 (DW_TAG_base_type)
|
||||
mdstring, ;; Name (may be "" for anonymous types)
|
||||
i32, ;; Line number where defined (may be 0)
|
||||
i64, ;; Size in bits
|
||||
i64, ;; Alignment in bits
|
||||
i64, ;; Offset in bits
|
||||
i32, ;; Flags
|
||||
i32 ;; DWARF type encoding
|
||||
),
|
||||
metadata, ;; Source directory (including trailing slash) & file pair (may be null)
|
||||
metadata ;; Reference to context
|
||||
}
|
||||
|
||||
These descriptors define primitive types used in the code. Example ``int``,
|
||||
``bool`` and ``float``. The context provides the scope of the type, which is
|
||||
usually the top level. Since basic types are not usually user defined the
|
||||
context and line number can be left as NULL and 0. The size, alignment and
|
||||
offset are expressed in bits and can be 64 bit values. The alignment is used
|
||||
to round the offset when embedded in a :ref:`composite type
|
||||
<format_composite_type>` (example to keep float doubles on 64 bit boundaries).
|
||||
The offset is the bit offset if embedded in a :ref:`composite type
|
||||
<format_composite_type>`.
|
||||
|
||||
The type encoding provides the details of the type. The values are typically
|
||||
one of the following:
|
||||
|
||||
.. code-block:: llvm
|
||||
|
||||
DW_ATE_address = 1
|
||||
DW_ATE_boolean = 2
|
||||
DW_ATE_float = 4
|
||||
DW_ATE_signed = 5
|
||||
DW_ATE_signed_char = 6
|
||||
DW_ATE_unsigned = 7
|
||||
DW_ATE_unsigned_char = 8
|
||||
|
||||
.. _format_derived_type:
|
||||
|
||||
Derived type descriptors
|
||||
^^^^^^^^^^^^^^^^^^^^^^^^
|
||||
|
||||
.. code-block:: llvm
|
||||
|
||||
!5 = metadata !{
|
||||
DIHeader(
|
||||
i32, ;; Tag (see below)
|
||||
mdstring, ;; Name (may be "" for anonymous types)
|
||||
i32, ;; Line number where defined (may be 0)
|
||||
i64, ;; Size in bits
|
||||
i64, ;; Alignment in bits
|
||||
i64, ;; Offset in bits
|
||||
i32 ;; Flags to encode attributes, e.g. private
|
||||
),
|
||||
metadata, ;; Source directory (including trailing slash) & file pair (may be null)
|
||||
metadata, ;; Reference to context
|
||||
metadata, ;; Reference to type derived from
|
||||
metadata ;; (optional) Objective C property node
|
||||
}
|
||||
|
||||
These descriptors are used to define types derived from other types. The value
|
||||
of the tag varies depending on the meaning. The following are possible tag
|
||||
values:
|
||||
|
||||
.. code-block:: llvm
|
||||
|
||||
DW_TAG_formal_parameter = 5
|
||||
DW_TAG_member = 13
|
||||
DW_TAG_pointer_type = 15
|
||||
DW_TAG_reference_type = 16
|
||||
DW_TAG_typedef = 22
|
||||
DW_TAG_ptr_to_member_type = 31
|
||||
DW_TAG_const_type = 38
|
||||
DW_TAG_volatile_type = 53
|
||||
DW_TAG_restrict_type = 55
|
||||
|
||||
``DW_TAG_member`` is used to define a member of a :ref:`composite type
|
||||
<format_composite_type>` or :ref:`subprogram <format_subprograms>`. The type
|
||||
of the member is the :ref:`derived type <format_derived_type>`.
|
||||
``DW_TAG_formal_parameter`` is used to define a member which is a formal
|
||||
argument of a subprogram.
|
||||
|
||||
``DW_TAG_typedef`` is used to provide a name for the derived type.
|
||||
|
||||
``DW_TAG_pointer_type``, ``DW_TAG_reference_type``, ``DW_TAG_const_type``,
|
||||
``DW_TAG_volatile_type`` and ``DW_TAG_restrict_type`` are used to qualify the
|
||||
:ref:`derived type <format_derived_type>`.
|
||||
|
||||
:ref:`Derived type <format_derived_type>` location can be determined from the
|
||||
context and line number. The size, alignment and offset are expressed in bits
|
||||
and can be 64 bit values. The alignment is used to round the offset when
|
||||
embedded in a :ref:`composite type <format_composite_type>` (example to keep
|
||||
float doubles on 64 bit boundaries.) The offset is the bit offset if embedded
|
||||
in a :ref:`composite type <format_composite_type>`.
|
||||
|
||||
Note that the ``void *`` type is expressed as a type derived from NULL.
|
||||
|
||||
.. _format_composite_type:
|
||||
|
||||
Composite type descriptors
|
||||
^^^^^^^^^^^^^^^^^^^^^^^^^^
|
||||
|
||||
.. code-block:: llvm
|
||||
|
||||
!6 = metadata !{
|
||||
DIHeader(
|
||||
i32, ;; Tag (see below)
|
||||
mdstring, ;; Name (may be "" for anonymous types)
|
||||
i32, ;; Line number where defined (may be 0)
|
||||
i64, ;; Size in bits
|
||||
i64, ;; Alignment in bits
|
||||
i64, ;; Offset in bits
|
||||
i32, ;; Flags
|
||||
i32 ;; Runtime languages
|
||||
),
|
||||
metadata, ;; Source directory (including trailing slash) & file pair (may be null)
|
||||
metadata, ;; Reference to context
|
||||
metadata, ;; Reference to type derived from
|
||||
metadata, ;; Reference to array of member descriptors
|
||||
metadata, ;; Base type containing the vtable pointer for this type
|
||||
metadata, ;; Template parameters
|
||||
mdstring ;; A unique identifier for type uniquing purpose (may be null)
|
||||
}
|
||||
|
||||
These descriptors are used to define types that are composed of 0 or more
|
||||
elements. The value of the tag varies depending on the meaning. The following
|
||||
are possible tag values:
|
||||
|
||||
.. code-block:: llvm
|
||||
|
||||
DW_TAG_array_type = 1
|
||||
DW_TAG_enumeration_type = 4
|
||||
DW_TAG_structure_type = 19
|
||||
DW_TAG_union_type = 23
|
||||
DW_TAG_subroutine_type = 21
|
||||
DW_TAG_inheritance = 28
|
||||
|
||||
The vector flag indicates that an array type is a native packed vector.
|
||||
|
||||
The members of array types (tag = ``DW_TAG_array_type``) are
|
||||
:ref:`subrange descriptors <format_subrange>`, each
|
||||
representing the range of subscripts at that level of indexing.
|
||||
|
||||
The members of enumeration types (tag = ``DW_TAG_enumeration_type``) are
|
||||
:ref:`enumerator descriptors <format_enumerator>`, each representing the
|
||||
definition of enumeration value for the set. All enumeration type descriptors
|
||||
are collected inside the named metadata ``!llvm.dbg.cu``.
|
||||
|
||||
The members of structure (tag = ``DW_TAG_structure_type``) or union (tag =
|
||||
``DW_TAG_union_type``) types are any one of the :ref:`basic
|
||||
<format_basic_type>`, :ref:`derived <format_derived_type>` or :ref:`composite
|
||||
<format_composite_type>` type descriptors, each representing a field member of
|
||||
the structure or union.
|
||||
|
||||
For C++ classes (tag = ``DW_TAG_structure_type``), member descriptors provide
|
||||
information about base classes, static members and member functions. If a
|
||||
member is a :ref:`derived type descriptor <format_derived_type>` and has a tag
|
||||
of ``DW_TAG_inheritance``, then the type represents a base class. If the member
|
||||
of is a :ref:`global variable descriptor <format_global_variables>` then it
|
||||
represents a static member. And, if the member is a :ref:`subprogram
|
||||
descriptor <format_subprograms>` then it represents a member function. For
|
||||
static members and member functions, ``getName()`` returns the members link or
|
||||
the C++ mangled name. ``getDisplayName()`` the simplied version of the name.
|
||||
|
||||
The first member of subroutine (tag = ``DW_TAG_subroutine_type``) type elements
|
||||
is the return type for the subroutine. The remaining elements are the formal
|
||||
arguments to the subroutine.
|
||||
|
||||
:ref:`Composite type <format_composite_type>` location can be determined from
|
||||
the context and line number. The size, alignment and offset are expressed in
|
||||
bits and can be 64 bit values. The alignment is used to round the offset when
|
||||
embedded in a :ref:`composite type <format_composite_type>` (as an example, to
|
||||
keep float doubles on 64 bit boundaries). The offset is the bit offset if
|
||||
embedded in a :ref:`composite type <format_composite_type>`.
|
||||
|
||||
.. _format_subrange:
|
||||
|
||||
Subrange descriptors
|
||||
^^^^^^^^^^^^^^^^^^^^
|
||||
|
||||
.. code-block:: llvm
|
||||
|
||||
!42 = metadata !{
|
||||
DIHeader(
|
||||
i32, ;; Tag = 33 (DW_TAG_subrange_type)
|
||||
i64, ;; Low value
|
||||
i64 ;; High value
|
||||
)
|
||||
}
|
||||
|
||||
These descriptors are used to define ranges of array subscripts for an array
|
||||
:ref:`composite type <format_composite_type>`. The low value defines the lower
|
||||
bounds typically zero for C/C++. The high value is the upper bounds. Values
|
||||
are 64 bit. ``High - Low + 1`` is the size of the array. If ``Low > High``
|
||||
the array bounds are not included in generated debugging information.
|
||||
|
||||
.. _format_enumerator:
|
||||
|
||||
Enumerator descriptors
|
||||
^^^^^^^^^^^^^^^^^^^^^^
|
||||
|
||||
.. code-block:: llvm
|
||||
|
||||
!6 = metadata !{
|
||||
DIHeader(
|
||||
i32, ;; Tag = 40 (DW_TAG_enumerator)
|
||||
mdstring, ;; Name
|
||||
i64 ;; Value
|
||||
)
|
||||
}
|
||||
|
||||
These descriptors are used to define members of an enumeration :ref:`composite
|
||||
type <format_composite_type>`, it associates the name to the value.
|
||||
|
||||
Local variables
|
||||
^^^^^^^^^^^^^^^
|
||||
|
||||
.. code-block:: llvm
|
||||
|
||||
!7 = metadata !{
|
||||
DIHeader(
|
||||
i32, ;; Tag (see below)
|
||||
mdstring, ;; Name
|
||||
i32, ;; 24 bit - Line number where defined
|
||||
;; 8 bit - Argument number. 1 indicates 1st argument.
|
||||
i32 ;; flags
|
||||
),
|
||||
metadata, ;; Context
|
||||
metadata, ;; Reference to file where defined
|
||||
metadata, ;; Reference to the type descriptor
|
||||
metadata ;; (optional) Reference to inline location
|
||||
}
|
||||
|
||||
These descriptors are used to define variables local to a sub program. The
|
||||
value of the tag depends on the usage of the variable:
|
||||
|
||||
.. code-block:: llvm
|
||||
|
||||
DW_TAG_auto_variable = 256
|
||||
DW_TAG_arg_variable = 257
|
||||
|
||||
An auto variable is any variable declared in the body of the function. An
|
||||
argument variable is any variable that appears as a formal argument to the
|
||||
function.
|
||||
|
||||
The context is either the subprogram or block where the variable is defined.
|
||||
Name the source variable name. Context and line indicate where the variable
|
||||
was defined. Type descriptor defines the declared type of the variable.
|
||||
|
||||
Complex Expressions
|
||||
^^^^^^^^^^^^^^^^^^^
|
||||
.. code-block:: llvm
|
||||
|
||||
!8 = metadata !{
|
||||
i32, ;; DW_TAG_expression
|
||||
...
|
||||
}
|
||||
|
||||
Complex expressions describe variable storage locations in terms of
|
||||
prefix-notated DWARF expressions. Currently the only supported
|
||||
operators are ``DW_OP_plus``, ``DW_OP_deref``, and ``DW_OP_piece``.
|
||||
|
||||
The ``DW_OP_piece`` operator is used for (typically larger aggregate)
|
||||
variables that are fragmented across several locations. It takes two
|
||||
i32 arguments, an offset and a size in bytes to describe which piece
|
||||
of the variable is at this location.
|
||||
|
||||
Debug information descriptors are `specialized metadata nodes
|
||||
<LangRef.html#specialized-metadata>`_, first-class subclasses of ``Metadata``.
|
||||
|
||||
.. _format_common_intrinsics:
|
||||
|
||||
Debugger intrinsic functions
|
||||
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
||||
----------------------------
|
||||
|
||||
LLVM uses several intrinsic functions (name prefixed with "``llvm.dbg``") to
|
||||
provide debug information at various points in generated code.
|
||||
@ -643,24 +177,27 @@ provide debug information at various points in generated code.
|
||||
|
||||
.. code-block:: llvm
|
||||
|
||||
void %llvm.dbg.declare(metadata, metadata)
|
||||
void %llvm.dbg.declare(metadata, metadata, metadata)
|
||||
|
||||
This intrinsic provides information about a local element (e.g., variable).
|
||||
The first argument is metadata holding the alloca for the variable. The second
|
||||
argument is metadata containing a description of the variable.
|
||||
argument is a `local variable <LangRef.html#MDLocalVariable>`_ containing a
|
||||
description of the variable. The third argument is a `complex expression
|
||||
<LangRef.html#MDExpression>`_.
|
||||
|
||||
``llvm.dbg.value``
|
||||
^^^^^^^^^^^^^^^^^^
|
||||
|
||||
.. code-block:: llvm
|
||||
|
||||
void %llvm.dbg.value(metadata, i64, metadata)
|
||||
void %llvm.dbg.value(metadata, i64, metadata, metadata)
|
||||
|
||||
This intrinsic provides information when a user source variable is set to a new
|
||||
value. The first argument is the new value (wrapped as metadata). The second
|
||||
argument is the offset in the user source variable where the new value is
|
||||
written. The third argument is metadata containing a description of the user
|
||||
source variable.
|
||||
written. The third argument is a `local variable
|
||||
<LangRef.html#MDLocalVariable>`_ containing a description of the variable. The
|
||||
third argument is a `complex expression <LangRef.html#MDExpression>`_.
|
||||
|
||||
Object lifetimes and scoping
|
||||
============================
|
||||
@ -693,86 +230,61 @@ Compiled to LLVM, this function would be represented like this:
|
||||
|
||||
.. code-block:: llvm
|
||||
|
||||
; Function Attrs: nounwind ssp uwtable
|
||||
define void @foo() #0 {
|
||||
entry:
|
||||
%X = alloca i32, align 4
|
||||
%X = alloca i32, align 4
|
||||
%Y = alloca i32, align 4
|
||||
%Z = alloca i32, align 4
|
||||
call void @llvm.dbg.declare(metadata !{i32* %X}, metadata !10), !dbg !12
|
||||
; [debug line = 2:7] [debug variable = X]
|
||||
store i32 21, i32* %X, align 4, !dbg !12
|
||||
call void @llvm.dbg.declare(metadata !{i32* %Y}, metadata !13), !dbg !14
|
||||
; [debug line = 3:7] [debug variable = Y]
|
||||
store i32 22, i32* %Y, align 4, !dbg !14
|
||||
call void @llvm.dbg.declare(metadata !{i32* %Z}, metadata !15), !dbg !17
|
||||
; [debug line = 5:9] [debug variable = Z]
|
||||
store i32 23, i32* %Z, align 4, !dbg !17
|
||||
%0 = load i32* %X, align 4, !dbg !18
|
||||
[debug line = 6:5]
|
||||
store i32 %0, i32* %Z, align 4, !dbg !18
|
||||
%1 = load i32* %Y, align 4, !dbg !19
|
||||
[debug line = 8:3]
|
||||
store i32 %1, i32* %X, align 4, !dbg !19
|
||||
ret void, !dbg !20
|
||||
call void @llvm.dbg.declare(metadata i32* %X, metadata !11, metadata !13), !dbg !14
|
||||
store i32 21, i32* %X, align 4, !dbg !14
|
||||
call void @llvm.dbg.declare(metadata i32* %Y, metadata !15, metadata !13), !dbg !16
|
||||
store i32 22, i32* %Y, align 4, !dbg !16
|
||||
call void @llvm.dbg.declare(metadata i32* %Z, metadata !17, metadata !13), !dbg !19
|
||||
store i32 23, i32* %Z, align 4, !dbg !19
|
||||
%0 = load i32, i32* %X, align 4, !dbg !20
|
||||
store i32 %0, i32* %Z, align 4, !dbg !21
|
||||
%1 = load i32, i32* %Y, align 4, !dbg !22
|
||||
store i32 %1, i32* %X, align 4, !dbg !23
|
||||
ret void, !dbg !24
|
||||
}
|
||||
|
||||
; Function Attrs: nounwind readnone
|
||||
declare void @llvm.dbg.declare(metadata, metadata) #1
|
||||
declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
|
||||
|
||||
attributes #0 = { nounwind ssp uwtable "less-precise-fpmad"="false"
|
||||
"no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf"
|
||||
"no-infs-fp-math"="false" "no-nans-fp-math"="false"
|
||||
"stack-protector-buffer-size"="8" "unsafe-fp-math"="false"
|
||||
"use-soft-float"="false" }
|
||||
attributes #0 = { nounwind ssp uwtable "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
|
||||
attributes #1 = { nounwind readnone }
|
||||
|
||||
!llvm.dbg.cu = !{!0}
|
||||
!llvm.module.flags = !{!8}
|
||||
!llvm.ident = !{!9}
|
||||
!llvm.module.flags = !{!7, !8, !9}
|
||||
!llvm.ident = !{!10}
|
||||
|
||||
!0 = !MDCompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 3.7.0 (trunk 231150) (llvm/trunk 231154)", isOptimized: false, runtimeVersion: 0, emissionKind: 1, enums: !2, retainedTypes: !2, subprograms: !3, globals: !2, imports: !2)
|
||||
!1 = !MDFile(filename: "/dev/stdin", directory: "/Users/dexonsmith/data/llvm/debug-info")
|
||||
!2 = !{}
|
||||
!3 = !{!4}
|
||||
!4 = !MDSubprogram(name: "foo", scope: !1, file: !1, line: 1, type: !5, isLocal: false, isDefinition: true, scopeLine: 1, isOptimized: false, function: void ()* @foo, variables: !2)
|
||||
!5 = !MDSubroutineType(types: !6)
|
||||
!6 = !{null}
|
||||
!7 = !{i32 2, !"Dwarf Version", i32 2}
|
||||
!8 = !{i32 2, !"Debug Info Version", i32 3}
|
||||
!9 = !{i32 1, !"PIC Level", i32 2}
|
||||
!10 = !{!"clang version 3.7.0 (trunk 231150) (llvm/trunk 231154)"}
|
||||
!11 = !MDLocalVariable(tag: DW_TAG_auto_variable, name: "X", scope: !4, file: !1, line: 2, type: !12)
|
||||
!12 = !MDBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
|
||||
!13 = !MDExpression()
|
||||
!14 = !MDLocation(line: 2, column: 9, scope: !4)
|
||||
!15 = !MDLocalVariable(tag: DW_TAG_auto_variable, name: "Y", scope: !4, file: !1, line: 3, type: !12)
|
||||
!16 = !MDLocation(line: 3, column: 9, scope: !4)
|
||||
!17 = !MDLocalVariable(tag: DW_TAG_auto_variable, name: "Z", scope: !18, file: !1, line: 5, type: !12)
|
||||
!18 = distinct !MDLexicalBlock(scope: !4, file: !1, line: 4, column: 5)
|
||||
!19 = !MDLocation(line: 5, column: 11, scope: !18)
|
||||
!20 = !MDLocation(line: 6, column: 11, scope: !18)
|
||||
!21 = !MDLocation(line: 6, column: 9, scope: !18)
|
||||
!22 = !MDLocation(line: 8, column: 9, scope: !4)
|
||||
!23 = !MDLocation(line: 8, column: 7, scope: !4)
|
||||
!24 = !MDLocation(line: 9, column: 3, scope: !4)
|
||||
|
||||
!0 = metadata !{i32 786449, metadata !1, i32 12,
|
||||
metadata !"clang version 3.4 (trunk 193128) (llvm/trunk 193139)",
|
||||
i1 false, metadata !"", i32 0, metadata !2, metadata !2, metadata !3,
|
||||
metadata !2, metadata !2, metadata !""} ; [ DW_TAG_compile_unit ] \
|
||||
[/private/tmp/foo.c] \
|
||||
[DW_LANG_C99]
|
||||
!1 = metadata !{metadata !"t.c", metadata !"/private/tmp"}
|
||||
!2 = metadata !{i32 0}
|
||||
!3 = metadata !{metadata !4}
|
||||
!4 = metadata !{i32 786478, metadata !1, metadata !5, metadata !"foo",
|
||||
metadata !"foo", metadata !"", i32 1, metadata !6,
|
||||
i1 false, i1 true, i32 0, i32 0, null, i32 0, i1 false,
|
||||
void ()* @foo, null, null, metadata !2, i32 1}
|
||||
; [ DW_TAG_subprogram ] [line 1] [def] [foo]
|
||||
!5 = metadata !{i32 786473, metadata !1} ; [ DW_TAG_file_type ] \
|
||||
[/private/tmp/t.c]
|
||||
!6 = metadata !{i32 786453, i32 0, null, metadata !"", i32 0, i64 0, i64 0,
|
||||
i64 0, i32 0, null, metadata !7, i32 0, null, null, null}
|
||||
; [ DW_TAG_subroutine_type ] \
|
||||
[line 0, size 0, align 0, offset 0] [from ]
|
||||
!7 = metadata !{null}
|
||||
!8 = metadata !{i32 2, metadata !"Dwarf Version", i32 2}
|
||||
!9 = metadata !{metadata !"clang version 3.4 (trunk 193128) (llvm/trunk 193139)"}
|
||||
!10 = metadata !{i32 786688, metadata !4, metadata !"X", metadata !5, i32 2,
|
||||
metadata !11, i32 0, i32 0} ; [ DW_TAG_auto_variable ] [X] \
|
||||
[line 2]
|
||||
!11 = metadata !{i32 786468, null, null, metadata !"int", i32 0, i64 32,
|
||||
i64 32, i64 0, i32 0, i32 5} ; [ DW_TAG_base_type ] [int] \
|
||||
[line 0, size 32, align 32, offset 0, enc DW_ATE_signed]
|
||||
!12 = metadata !{i32 2, i32 0, metadata !4, null}
|
||||
!13 = metadata !{i32 786688, metadata !4, metadata !"Y", metadata !5, i32 3,
|
||||
metadata !11, i32 0, i32 0} ; [ DW_TAG_auto_variable ] [Y] \
|
||||
[line 3]
|
||||
!14 = metadata !{i32 3, i32 0, metadata !4, null}
|
||||
!15 = metadata !{i32 786688, metadata !16, metadata !"Z", metadata !5, i32 5,
|
||||
metadata !11, i32 0, i32 0} ; [ DW_TAG_auto_variable ] [Z] \
|
||||
[line 5]
|
||||
!16 = metadata !{i32 786443, metadata !1, metadata !4, i32 4, i32 0, i32 0} \
|
||||
; [ DW_TAG_lexical_block ] [/private/tmp/t.c]
|
||||
!17 = metadata !{i32 5, i32 0, metadata !16, null}
|
||||
!18 = metadata !{i32 6, i32 0, metadata !16, null}
|
||||
!19 = metadata !{i32 8, i32 0, metadata !4, null} ; [ DW_TAG_imported_declaration ]
|
||||
!20 = metadata !{i32 9, i32 0, metadata !4, null}
|
||||
|
||||
This example illustrates a few important details about LLVM debugging
|
||||
information. In particular, it shows how the ``llvm.dbg.declare`` intrinsic and
|
||||
@ -782,27 +294,24 @@ variable definitions, and the code used to implement the function.
|
||||
|
||||
.. code-block:: llvm
|
||||
|
||||
call void @llvm.dbg.declare(metadata !{i32* %X}, metadata !10), !dbg !12
|
||||
call void @llvm.dbg.declare(metadata i32* %X, metadata !11, metadata !13), !dbg !14
|
||||
; [debug line = 2:7] [debug variable = X]
|
||||
|
||||
The first intrinsic ``%llvm.dbg.declare`` encodes debugging information for the
|
||||
variable ``X``. The metadata ``!dbg !12`` attached to the intrinsic provides
|
||||
variable ``X``. The metadata ``!dbg !14`` attached to the intrinsic provides
|
||||
scope information for the variable ``X``.
|
||||
|
||||
.. code-block:: llvm
|
||||
|
||||
!12 = metadata !{i32 2, i32 0, metadata !4, null}
|
||||
!4 = metadata !{i32 786478, metadata !1, metadata !5, metadata !"foo",
|
||||
metadata !"foo", metadata !"", i32 1, metadata !6,
|
||||
i1 false, i1 true, i32 0, i32 0, null, i32 0, i1 false,
|
||||
void ()* @foo, null, null, metadata !2, i32 1}
|
||||
; [ DW_TAG_subprogram ] [line 1] [def] [foo]
|
||||
!14 = !MDLocation(line: 2, column: 9, scope: !4)
|
||||
!4 = !MDSubprogram(name: "foo", scope: !1, file: !1, line: 1, type: !5,
|
||||
isLocal: false, isDefinition: true, scopeLine: 1,
|
||||
isOptimized: false, function: void ()* @foo,
|
||||
variables: !2)
|
||||
|
||||
Here ``!12`` is metadata providing location information. It has four fields:
|
||||
line number, column number, scope, and original scope. The original scope
|
||||
represents inline location if this instruction is inlined inside a caller, and
|
||||
is null otherwise. In this example, scope is encoded by ``!4``, a
|
||||
:ref:`subprogram descriptor <format_subprograms>`. This way the location
|
||||
Here ``!14`` is metadata providing `location information
|
||||
<LangRef.html#MDLocation>`_. In this example, scope is encoded by ``!4``, a
|
||||
`subprogram descriptor <LangRef.html#MDSubprogram>`_. This way the location
|
||||
information attached to the intrinsics indicates that the variable ``X`` is
|
||||
declared at line number 2 at a function level scope in function ``foo``.
|
||||
|
||||
@ -810,22 +319,21 @@ Now lets take another example.
|
||||
|
||||
.. code-block:: llvm
|
||||
|
||||
call void @llvm.dbg.declare(metadata !{i32* %Z}, metadata !15), !dbg !17
|
||||
call void @llvm.dbg.declare(metadata i32* %Z, metadata !17, metadata !13), !dbg !19
|
||||
; [debug line = 5:9] [debug variable = Z]
|
||||
|
||||
The third intrinsic ``%llvm.dbg.declare`` encodes debugging information for
|
||||
variable ``Z``. The metadata ``!dbg !17`` attached to the intrinsic provides
|
||||
variable ``Z``. The metadata ``!dbg !19`` attached to the intrinsic provides
|
||||
scope information for the variable ``Z``.
|
||||
|
||||
.. code-block:: llvm
|
||||
|
||||
!16 = metadata !{i32 786443, metadata !1, metadata !4, i32 4, i32 0, i32 0} \
|
||||
; [ DW_TAG_lexical_block ] [/private/tmp/t.c]
|
||||
!17 = metadata !{i32 5, i32 0, metadata !16, null}
|
||||
!18 = distinct !MDLexicalBlock(scope: !4, file: !1, line: 4, column: 5)
|
||||
!19 = !MDLocation(line: 5, column: 11, scope: !18)
|
||||
|
||||
Here ``!15`` indicates that ``Z`` is declared at line number 5 and
|
||||
column number 0 inside of lexical scope ``!16``. The lexical scope itself
|
||||
resides inside of subprogram ``!4`` described above.
|
||||
Here ``!19`` indicates that ``Z`` is declared at line number 5 and column
|
||||
number 0 inside of lexical scope ``!18``. The lexical scope itself resides
|
||||
inside of subprogram ``!4`` described above.
|
||||
|
||||
The scope information attached with each instruction provides a straightforward
|
||||
way to find instructions covered by a scope.
|
||||
@ -888,98 +396,52 @@ a C/C++ front-end would generate the following descriptors:
|
||||
;; Define the global itself.
|
||||
;;
|
||||
@MyGlobal = global i32 100, align 4
|
||||
...
|
||||
|
||||
;;
|
||||
;; List of debug info of globals
|
||||
;;
|
||||
!llvm.dbg.cu = !{!0}
|
||||
|
||||
;; Some unrelated metadata.
|
||||
!llvm.module.flags = !{!6, !7}
|
||||
|
||||
;; Define the compile unit.
|
||||
!0 = metadata !{
|
||||
; Header(
|
||||
; i32 17, ;; Tag
|
||||
; i32 0, ;; Context
|
||||
; i32 4, ;; Language
|
||||
; metadata !"clang version 3.6.0 ", ;; Producer
|
||||
; i1 false, ;; "isOptimized"?
|
||||
; metadata !"", ;; Flags
|
||||
; i32 0, ;; Runtime Version
|
||||
; "", ;; Split debug filename
|
||||
; 1 ;; Full debug info
|
||||
; )
|
||||
metadata !"0x11\0012\00clang version 3.6.0 \000\00\000\00\001",
|
||||
metadata !1, ;; File
|
||||
metadata !2, ;; Enum Types
|
||||
metadata !2, ;; Retained Types
|
||||
metadata !2, ;; Subprograms
|
||||
metadata !3, ;; Global Variables
|
||||
metadata !2 ;; Imported entities
|
||||
} ; [ DW_TAG_compile_unit ]
|
||||
|
||||
;; The file/directory pair.
|
||||
!1 = metadata !{
|
||||
metadata !"foo.c", ;; Filename
|
||||
metadata !"/Users/dexonsmith/data/llvm/debug-info" ;; Directory
|
||||
}
|
||||
|
||||
;; An empty array.
|
||||
!2 = metadata !{}
|
||||
|
||||
;; The Array of Global Variables
|
||||
!3 = metadata !{
|
||||
metadata !4
|
||||
}
|
||||
|
||||
;;
|
||||
;; Define the global variable itself.
|
||||
;;
|
||||
!4 = metadata !{
|
||||
; Header(
|
||||
; i32 52, ;; Tag
|
||||
; metadata !"MyGlobal", ;; Name
|
||||
; metadata !"MyGlobal", ;; Display Name
|
||||
; metadata !"", ;; Linkage Name
|
||||
; i32 1, ;; Line
|
||||
; i32 0, ;; IsLocalToUnit
|
||||
; i32 1 ;; IsDefinition
|
||||
; )
|
||||
metadata !"0x34\00MyGlobal\00MyGlobal\00\001\000\001",
|
||||
null, ;; Unused
|
||||
metadata !5, ;; File
|
||||
metadata !6, ;; Type
|
||||
i32* @MyGlobal, ;; LLVM-IR Value
|
||||
null ;; Static member declaration
|
||||
} ; [ DW_TAG_variable ]
|
||||
!0 = !MDCompileUnit(language: DW_LANG_C99, file: !1,
|
||||
producer:
|
||||
"clang version 3.7.0 (trunk 231150) (llvm/trunk 231154)",
|
||||
isOptimized: false, runtimeVersion: 0, emissionKind: 1,
|
||||
enums: !2, retainedTypes: !2, subprograms: !2, globals:
|
||||
!3, imports: !2)
|
||||
|
||||
;;
|
||||
;; Define the file
|
||||
;;
|
||||
!5 = metadata !{
|
||||
; Header(
|
||||
; i32 41 ;; Tag
|
||||
; )
|
||||
metadata !"0x29",
|
||||
metadata !1 ;; File/directory pair
|
||||
} ; [ DW_TAG_file_type ]
|
||||
!1 = !MDFile(filename: "/dev/stdin",
|
||||
directory: "/Users/dexonsmith/data/llvm/debug-info")
|
||||
|
||||
;; An empty array.
|
||||
!2 = !{}
|
||||
|
||||
;; The Array of Global Variables
|
||||
!3 = !{!4}
|
||||
|
||||
;;
|
||||
;; Define the global variable itself.
|
||||
;;
|
||||
!4 = !MDGlobalVariable(name: "MyGlobal", scope: !0, file: !1, line: 1,
|
||||
type: !5, isLocal: false, isDefinition: true,
|
||||
variable: i32* @MyGlobal)
|
||||
|
||||
;;
|
||||
;; Define the type
|
||||
;;
|
||||
!6 = metadata !{
|
||||
; Header(
|
||||
; i32 36, ;; Tag
|
||||
; metadata !"int", ;; Name
|
||||
; i32 0, ;; Line
|
||||
; i64 32, ;; Size in Bits
|
||||
; i64 32, ;; Align in Bits
|
||||
; i64 0, ;; Offset
|
||||
; i32 0, ;; Flags
|
||||
; i32 5 ;; Encoding
|
||||
; )
|
||||
metadata !"0x24\00int\000\0032\0032\000\000\005",
|
||||
null, ;; Unused
|
||||
null ;; Unused
|
||||
} ; [ DW_TAG_base_type ]
|
||||
!5 = !MDBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
|
||||
|
||||
;; Dwarf version to output.
|
||||
!6 = !{i32 2, !"Dwarf Version", i32 2}
|
||||
|
||||
;; Debug info schema version.
|
||||
!7 = !{i32 2, !"Debug Info Version", i32 3}
|
||||
|
||||
C/C++ function information
|
||||
--------------------------
|
||||
@ -999,31 +461,10 @@ a C/C++ front-end would generate the following descriptors:
|
||||
;;
|
||||
;; Define the anchor for subprograms.
|
||||
;;
|
||||
!6 = metadata !{
|
||||
; Header(
|
||||
; i32 46, ;; Tag
|
||||
; metadata !"main", ;; Name
|
||||
; metadata !"main", ;; Display name
|
||||
; metadata !"", ;; Linkage name
|
||||
; i32 1, ;; Line number
|
||||
; i1 false, ;; Is local
|
||||
; i1 true, ;; Is definition
|
||||
; i32 0, ;; Virtuality attribute, e.g. pure virtual function
|
||||
; i32 0, ;; Index into virtual table for C++ methods
|
||||
; i32 256, ;; Flags
|
||||
; i1 0, ;; True if this function is optimized
|
||||
; 1 ;; Line number of the opening '{' of the function
|
||||
; )
|
||||
metadata !"0x2e\00main\00main\00\001\000\001\000\000\00256\000\001",
|
||||
metadata !1, ;; File
|
||||
metadata !5, ;; Context
|
||||
metadata !6, ;; Type
|
||||
null, ;; Containing type
|
||||
i32 (i32, i8**)* @main, ;; Pointer to llvm::Function
|
||||
null, ;; Function template parameters
|
||||
null, ;; Function declaration
|
||||
metadata !2 ;; List of function variables (emitted when optimizing)
|
||||
}
|
||||
!4 = !MDSubprogram(name: "main", scope: !1, file: !1, line: 1, type: !5,
|
||||
isLocal: false, isDefinition: true, scopeLine: 1,
|
||||
flags: DIFlagPrototyped, isOptimized: false,
|
||||
function: i32 (i32, i8**)* @main, variables: !2)
|
||||
|
||||
;;
|
||||
;; Define the subprogram itself.
|
||||
|
||||
Loading…
Reference in New Issue
Block a user