diff options
Diffstat (limited to 'docs/SourceLevelDebugging.rst')
| -rw-r--r-- | docs/SourceLevelDebugging.rst | 22 |
1 files changed, 19 insertions, 3 deletions
diff --git a/docs/SourceLevelDebugging.rst b/docs/SourceLevelDebugging.rst index 41f8dbfab3dc..a9f5c3a08147 100644 --- a/docs/SourceLevelDebugging.rst +++ b/docs/SourceLevelDebugging.rst @@ -180,11 +180,27 @@ provide debug information at various points in generated code. 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 +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 a `local variable <LangRef.html#dilocalvariable>`_ containing a description of the variable. The third argument is a `complex expression -<LangRef.html#diexpression>`_. +<LangRef.html#diexpression>`_. An `llvm.dbg.declare` instrinsic describes the +*location* of a source variable. + +.. code-block:: llvm + + %i.addr = alloca i32, align 4 + call void @llvm.dbg.declare(metadata i32* %i.addr, metadata !1, metadata !2), !dbg !3 + !1 = !DILocalVariable(name: "i", ...) ; int i + !2 = !DIExpression() + !3 = !DILocation(...) + ... + %buffer = alloca [256 x i8], align 8 + ; The address of i is buffer+64. + call void @llvm.dbg.declare(metadata [256 x i8]* %buffer, metadata !1, metadata !2) + !1 = !DILocalVariable(name: "i", ...) ; int i + !2 = !DIExpression(DW_OP_plus, 64) + ``llvm.dbg.value`` ^^^^^^^^^^^^^^^^^^ |