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Diffstat (limited to 'llvm/docs/SourceLevelDebugging.rst')
| -rw-r--r-- | llvm/docs/SourceLevelDebugging.rst | 17 |
1 files changed, 15 insertions, 2 deletions
diff --git a/llvm/docs/SourceLevelDebugging.rst b/llvm/docs/SourceLevelDebugging.rst index f7b62cb0872..8acd90122b4 100644 --- a/llvm/docs/SourceLevelDebugging.rst +++ b/llvm/docs/SourceLevelDebugging.rst @@ -571,7 +571,7 @@ Local variables metadata, ;; Reference to the type descriptor i32, ;; flags metadata ;; (optional) Reference to inline location - metadata ;; (optional) Reference to a complex expression (see below) + metadata ;; (optional) Reference to a complex expression. } These descriptors are used to define variables local to a sub program. The @@ -590,7 +590,20 @@ 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. -The ``OpPiece`` operator is used for (typically larger aggregate) +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. |
