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.
Bootstrapped and regression tested powerpc64le-linux. OK?
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.
diff --git a/gcc/config/rs6000/linux64.h b/gcc/config/rs6000/linux64.h
index 2ded3301282..2de1097d3ec 100644
--- a/gcc/config/rs6000/linux64.h
+++ b/gcc/config/rs6000/linux64.h
@@ -132,20 +132,25 @@ 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 \
+ || !(TARGET_PCREL \
+ || (PCREL_SUPPORTED_BY_OS \
+ && (rs6000_isa_flags_explicit \
+ & OPTION_MASK_PCREL) == 0))) \
+ 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
--
Alan Modra
Australia Development Lab, IBM
