From c6be439b37702f6ac4c2fc447c6f3ed1042b80a3 Mon Sep 17 00:00:00 2001 From: Alan Modra Date: Mon, 28 Sep 2020 16:23:01 +0930 Subject: [PATCH] [RS6000] -mno-minimal-toc vs. power10 pcrelative We've had this hack in the libgcc config to build libgcc with -mcmodel=small for powerpc64 for a long time. It wouldn't be a bad thing if someone who knows the multilib machinery well could arrange for -mcmodel=small to be passed just for ppc64 when building for earlier than power10. But for now, make -mno-minimal-toc do nothing when pcrel. Which will do the right thing for any project that has copied libgcc's trick. We want this if configuring using --with-cpu=power10 to build a power10 pcrel libgcc. --mcmodel=small turns off pcrel. gcc/ * config/rs6000/linux64.h (SUBSUBTARGET_OVERRIDE_OPTIONS): Don't set -mcmodel=small for -mno-minimal-toc when pcrel. libgcc/ * config/rs6000/t-linux: Document purpose of -mno-minimal-toc. --- gcc/config/rs6000/linux64.h | 17 +++++++++++++---- libgcc/config/rs6000/t-linux | 7 ++++++- 2 files changed, 19 insertions(+), 5 deletions(-) diff --git a/gcc/config/rs6000/linux64.h b/gcc/config/rs6000/linux64.h index 2ded3301282..5c9f8e3d7af 100644 --- a/gcc/config/rs6000/linux64.h +++ b/gcc/config/rs6000/linux64.h @@ -132,20 +132,29 @@ extern int dot_symbols; if ((rs6000_isa_flags & OPTION_MASK_POWERPC64) == 0) \ { \ rs6000_isa_flags |= OPTION_MASK_POWERPC64; \ - error ("%<-m64%> requires a PowerPC64 cpu"); \ + error ("%<-m64%> requires a PowerPC64 cpu"); \ } \ + if (!global_options_set.x_rs6000_current_cmodel) \ + SET_CMODEL (CMODEL_MEDIUM); \ if ((rs6000_isa_flags_explicit \ & OPTION_MASK_MINIMAL_TOC) != 0) \ { \ if (global_options_set.x_rs6000_current_cmodel \ && rs6000_current_cmodel != CMODEL_SMALL) \ error ("%<-mcmodel incompatible with other toc options%>"); \ - SET_CMODEL (CMODEL_SMALL); \ + if (TARGET_MINIMAL_TOC) \ + SET_CMODEL (CMODEL_SMALL); \ + else if (TARGET_PCREL \ + || (PCREL_SUPPORTED_BY_OS \ + && (rs6000_isa_flags_explicit \ + & OPTION_MASK_PCREL) == 0)) \ + /* Ignore -mno-minimal-toc. */ \ + ; \ + else \ + SET_CMODEL (CMODEL_SMALL); \ } \ else \ { \ - if (!global_options_set.x_rs6000_current_cmodel) \ - SET_CMODEL (CMODEL_MEDIUM); \ if (rs6000_current_cmodel != CMODEL_SMALL) \ { \ if (!global_options_set.x_TARGET_NO_FP_IN_TOC) \ diff --git a/libgcc/config/rs6000/t-linux b/libgcc/config/rs6000/t-linux index 4f6d4c4a4d2..ed821947b66 100644 --- a/libgcc/config/rs6000/t-linux +++ b/libgcc/config/rs6000/t-linux @@ -1,3 +1,8 @@ SHLIB_MAPFILES += $(srcdir)/config/rs6000/libgcc-glibc.ver -HOST_LIBGCC2_CFLAGS += -mlong-double-128 -mno-minimal-toc +HOST_LIBGCC2_CFLAGS += -mlong-double-128 + +# This is a way of selecting -mcmodel=small for ppc64, which gives +# smaller and faster libgcc code. Directly specifying -mcmodel=small +# would need to take into account targets for which -mcmodel is invalid. +HOST_LIBGCC2_CFLAGS += -mno-minimal-toc -- 2.30.2