From a4426641f00cd2c293c91e881ab31faaf76b20fb Mon Sep 17 00:00:00 2001 From: Nathan Chancellor Date: Tue, 5 Dec 2023 16:53:52 -0700 Subject: lib/Kconfig.debug: Update AS_HAS_NON_CONST_LEB128 comment and name Fangrui noted that the comment around CONFIG_AS_HAS_NON_CONST_LEB128 could be made more accurate because explicit .sleb128 directives are not emitted, only .uleb128 directives are. Rename the symbol to CONFIG_AS_HAS_NON_CONST_ULEB128 as a result. Further clarifications include replacing "symbol deltas" with the more accurate "label differences", noting that this issue has been resolved in newer binutils (2.41+), and it only occurs when a port uses RISC-V style linker relaxation. Suggested-by: Fangrui Song Signed-off-by: Nathan Chancellor Reviewed-by: Charlie Jenkins Link: https://lore.kernel.org/r/20231205-riscv-restrict-dwarf5-llvm-v2-3-aedf00a382ac@kernel.org Signed-off-by: Palmer Dabbelt --- lib/Kconfig.debug | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index a0ebce05a368..76c2cc697573 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -231,9 +231,10 @@ config DEBUG_INFO in the "Debug information" choice below, indicating that debug information will be generated for build targets. -# Clang is known to generate .{s,u}leb128 with symbol deltas with DWARF5, which -# some targets may not support: https://sourceware.org/bugzilla/show_bug.cgi?id=27215 -config AS_HAS_NON_CONST_LEB128 +# Clang generates .uleb128 with label differences for DWARF v5, a feature that +# older binutils ports do not support when utilizing RISC-V style linker +# relaxation: https://sourceware.org/bugzilla/show_bug.cgi?id=27215 +config AS_HAS_NON_CONST_ULEB128 def_bool $(as-instr,.uleb128 .Lexpr_end4 - .Lexpr_start3\n.Lexpr_start3:\n.Lexpr_end4:) choice @@ -258,7 +259,7 @@ config DEBUG_INFO_NONE config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT bool "Rely on the toolchain's implicit default DWARF version" select DEBUG_INFO - depends on !CC_IS_CLANG || AS_IS_LLVM || CLANG_VERSION < 140000 || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_LEB128) + depends on !CC_IS_CLANG || AS_IS_LLVM || CLANG_VERSION < 140000 || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_ULEB128) help The implicit default version of DWARF debug info produced by a toolchain changes over time. @@ -283,7 +284,7 @@ config DEBUG_INFO_DWARF5 bool "Generate DWARF Version 5 debuginfo" select DEBUG_INFO depends on !ARCH_HAS_BROKEN_DWARF5 - depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_LEB128) + depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_ULEB128) help Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc 5.0+ accepts the -gdwarf-5 flag but only had partial support for some -- cgit