dblaikie added a comment. In D103131#2814595 <https://reviews.llvm.org/D103131#2814595>, @kamleshbhalui wrote:
> In D103131#2814015 <https://reviews.llvm.org/D103131#2814015>, @dblaikie > wrote: > >> In D103131#2811969 <https://reviews.llvm.org/D103131#2811969>, >> @kamleshbhalui wrote: >> >>> In D103131#2811220 <https://reviews.llvm.org/D103131#2811220>, @dblaikie >>> wrote: >>> >>>> Any idea if the GDB test suite covers this functionality? I'd hope so, but >>>> maybe it doesn't. >>>> >>>> But yeah, at the moment I don't have any great reason to avoid the >>>> imported declaration form - so happy to go with that. >>> >>> Hi David, >>> >>> with imported declaration patch and with current patch(in review or say gcc >>> way) this case works ok(we can print type and value of newname) >>> $cat test.c >>> int oldname = 1; >>> extern int newname attribute((alias("oldname"))); >>> >>> but when we make newname static it works with current patch(in review or >>> say gcc way) but it does not work with imported decl >>> patch(https://reviews.llvm.org/D103131?id=347883). >>> >>> Should we go with gcc way or am I missing something? >>> note: used gdb debugger. >> >> An ideas what's happening when `newname` is static? Is the DWARF any >> different/interesting there? (since the DWARF for imported decl seems like >> it would have nothing to do with the linkange of the alias - since it >> doesn't refer to the actual alias in the object file, etc) > > There not much different apart from extern has external attribute. > **case 1) when `newname` is static** > > .debug_info contents: > 0x00000000: Compile Unit: length = 0x00000072, format = DWARF32, version = > 0x0004, abbr_offset = 0x0000, addr_size = 0x08 (next unit at 0x00000076) > > 0x0000000b: DW_TAG_compile_unit > DW_AT_producer ("clang version 13.0.0 > (g...@github.com:llvm/llvm-project.git > 4cd7169f5517167ef456e82c6dcae669bde6c725)") > DW_AT_language (DW_LANG_C99) > DW_AT_name ("test.c") > DW_AT_stmt_list (0x00000000) > DW_AT_comp_dir > ("/folk/kkumar/tcllvm/llvm-build-lldb-rel/bin") > DW_AT_low_pc (0x0000000000000000) > DW_AT_high_pc (0x0000000000000008) > > 0x0000002a: DW_TAG_variable > DW_AT_name ("oldname") > DW_AT_type (0x0000003f "int") > DW_AT_external (true) > DW_AT_decl_file > ("/folk/kkumar/tcllvm/llvm-build-lldb-rel/bin/test.c") > DW_AT_decl_line (1) > DW_AT_location (DW_OP_addr 0x0) > > 0x0000003f: DW_TAG_base_type > DW_AT_name ("int") > DW_AT_encoding (DW_ATE_signed) > DW_AT_byte_size (0x04) > > 0x00000046: DW_TAG_variable > DW_AT_name ("newname") > DW_AT_type (0x0000003f "int") > DW_AT_decl_file > ("/folk/kkumar/tcllvm/llvm-build-lldb-rel/bin/test.c") > DW_AT_decl_line (2) > DW_AT_declaration (true) > > 0x00000051: DW_TAG_imported_declaration > DW_AT_decl_file > ("/folk/kkumar/tcllvm/llvm-build-lldb-rel/bin/test.c") > DW_AT_decl_line (2) > DW_AT_import (0x00000046) > DW_AT_name ("newname") > > 0x0000005c: DW_TAG_subprogram > DW_AT_low_pc (0x0000000000000000) > DW_AT_high_pc (0x0000000000000008) > DW_AT_frame_base (DW_OP_reg6 RBP) > DW_AT_name ("main") > DW_AT_decl_file > ("/folk/kkumar/tcllvm/llvm-build-lldb-rel/bin/test.c") > DW_AT_decl_line (3) > DW_AT_type (0x0000003f "int") > DW_AT_external (true) > > 0x00000075: NULL > > **case 2) when `newname` is extern** > > .debug_info contents: > 0x00000000: Compile Unit: length = 0x00000072, format = DWARF32, version = > 0x0004, abbr_offset = 0x0000, addr_size = 0x08 (next unit at 0x00000076) > > 0x0000000b: DW_TAG_compile_unit > DW_AT_producer ("clang version 13.0.0 > (g...@github.com:llvm/llvm-project.git > 4cd7169f5517167ef456e82c6dcae669bde6c725)") > DW_AT_language (DW_LANG_C99) > DW_AT_name ("test.c") > DW_AT_stmt_list (0x00000000) > DW_AT_comp_dir > ("/folk/kkumar/tcllvm/llvm-build-lldb-rel/bin") > DW_AT_low_pc (0x0000000000000000) > DW_AT_high_pc (0x0000000000000008) > > 0x0000002a: DW_TAG_variable > DW_AT_name ("oldname") > DW_AT_type (0x0000003f "int") > DW_AT_external (true) > DW_AT_decl_file > ("/folk/kkumar/tcllvm/llvm-build-lldb-rel/bin/test.c") > DW_AT_decl_line (1) > DW_AT_location (DW_OP_addr 0x0) > > 0x0000003f: DW_TAG_base_type > DW_AT_name ("int") > DW_AT_encoding (DW_ATE_signed) > DW_AT_byte_size (0x04) > > 0x00000046: DW_TAG_variable > DW_AT_name ("newname") > DW_AT_type (0x0000003f "int") > DW_AT_external (true) > DW_AT_decl_file > ("/folk/kkumar/tcllvm/llvm-build-lldb-rel/bin/test.c") > DW_AT_decl_line (2) > DW_AT_declaration (true) > > 0x00000051: DW_TAG_imported_declaration > DW_AT_decl_file > ("/folk/kkumar/tcllvm/llvm-build-lldb-rel/bin/test.c") > DW_AT_decl_line (2) > DW_AT_import (0x00000046) > DW_AT_name ("newname") > > 0x0000005c: DW_TAG_subprogram > DW_AT_low_pc (0x0000000000000000) > DW_AT_high_pc (0x0000000000000008) > DW_AT_frame_base (DW_OP_reg6 RBP) > DW_AT_name ("main") > DW_AT_decl_file > ("/folk/kkumar/tcllvm/llvm-build-lldb-rel/bin/test.c") > DW_AT_decl_line (3) > DW_AT_type (0x0000003f "int") > DW_AT_external (true) > > 0x00000075: NULL This debug info looks confusing - it looks like it's using /both/ strategies. There's a `DW_TAG_variable` for `oldname` then a `DW_TAG_variable` declaration for `newname` then a `DW_TAG_imported_declaration` for `newname` from `newname`. I don't think that's a solution we'd want - either we have just the two `DW_TAG_variable`s, or we have the `oldname` `DW_TAG_variable` and a `DW_TAG_imported_declaration` that imports that `oldname` variable as `newname`, right? Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D103131/new/ https://reviews.llvm.org/D103131 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
