diff options
Diffstat (limited to 'llvm/docs')
| -rw-r--r-- | llvm/docs/SourceLevelDebugging.rst | 47 |
1 files changed, 26 insertions, 21 deletions
diff --git a/llvm/docs/SourceLevelDebugging.rst b/llvm/docs/SourceLevelDebugging.rst index 8c3142ed219..6f22f54ce4d 100644 --- a/llvm/docs/SourceLevelDebugging.rst +++ b/llvm/docs/SourceLevelDebugging.rst @@ -386,7 +386,7 @@ Given an integer global variable declared as follows: .. code-block:: c - int MyGlobal = 100; + _Alignas(8) int MyGlobal = 100; a C/C++ front-end would generate the following descriptors: @@ -395,54 +395,59 @@ a C/C++ front-end would generate the following descriptors: ;; ;; Define the global itself. ;; - @MyGlobal = global i32 100, align 4 + @MyGlobal = global i32 100, align 8, !dbg !0 ;; ;; List of debug info of globals ;; - !llvm.dbg.cu = !{!0} + !llvm.dbg.cu = !{!1} ;; Some unrelated metadata. !llvm.module.flags = !{!6, !7} + !llvm.ident = !{!8} + + ;; Define the global variable itself + !0 = distinct !DIGlobalVariable(name: "MyGlobal", scope: !1, file: !2, line: 1, type: !5, isLocal: false, isDefinition: true, align: 64) ;; Define the compile unit. - !0 = !DICompileUnit(language: DW_LANG_C99, file: !1, - producer: - "clang version 3.7.0 (trunk 231150) (llvm/trunk 231154)", - isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, - enums: !2, retainedTypes: !2, subprograms: !2, globals: - !3, imports: !2) + !1 = distinct !DICompileUnit(language: DW_LANG_C99, file: !2, + producer: "clang version 4.0.0 (http://llvm.org/git/clang.git ae4deadbea242e8ea517eef662c30443f75bd086) (http://llvm.org/git/llvm.git 818b4c1539df3e51dc7e62c89ead4abfd348827d)", + isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, + enums: !3, globals: !4) ;; ;; Define the file ;; - !1 = !DIFile(filename: "/dev/stdin", + !2 = !DIFile(filename: "/dev/stdin", directory: "/Users/dexonsmith/data/llvm/debug-info") ;; An empty array. - !2 = !{} + !3 = !{} ;; The Array of Global Variables - !3 = !{!4} - - ;; - ;; Define the global variable itself. - ;; - !4 = !DIGlobalVariable(name: "MyGlobal", scope: !0, file: !1, line: 1, - type: !5, isLocal: false, isDefinition: true, - variable: i32* @MyGlobal) + !4 = !{!0} ;; ;; Define the type ;; - !5 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed) + !5 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed) ;; Dwarf version to output. - !6 = !{i32 2, !"Dwarf Version", i32 2} + !6 = !{i32 2, !"Dwarf Version", i32 4} ;; Debug info schema version. !7 = !{i32 2, !"Debug Info Version", i32 3} + ;; Compiler identification + !8 = !{!"clang version 4.0.0 (http://llvm.org/git/clang.git ae4deadbea242e8ea517eef662c30443f75bd086) (http://llvm.org/git/llvm.git 818b4c1539df3e51dc7e62c89ead4abfd348827d)"} + + +The align value in DIGlobalVariable description specifies variable alignment in +case it was forced by C11 _Alignas(), C++11 alignas() keywords or compiler +attribute __attribute__((aligned ())). In other case (when this field is missing) +alignment is considered default. This is used when producing DWARF output +for DW_AT_alignment value. + C/C++ function information -------------------------- |
