On Thu, Jul 24, 2025 at 9:30 PM H.J. Lu <hjl.to...@gmail.com> wrote: > > On x86-64, __tls_get_addr is a normal function which doesn't preserve > vector registers. On i386, ___tls_get_addr preserve vector registers > only with the commit:
Can you please rephrase the above part? What does it mean to be a normal function in the context of this patch? Does the x86_64 compiler emit the normal ABI call (so the caller has to save and restore call-clobbered regs)? What is the difference to i386 ___tls_get_addr call? > 848f0e46f0 i386: Update ___tls_get_addr to preserve vector registers > > which fixed: > > https://sourceware.org/bugzilla/show_bug.cgi?id=32996 > > -mtls-dialect=gnu2 should be used instead with a fixed glibc for > > https://sourceware.org/bugzilla/show_bug.cgi?id=31372 > > with the commit: > > 0aac205a81 x86: Update _dl_tlsdesc_dynamic to preserve caller-saved registers > > Issue an error for -mtls-dialect=gnu with no_caller_saved_registers > attribute and suggest -mtls-dialect=gnu2 when __tls_get_addr is used. If these are fixed, why do we need to use -mtls-dialect=gnu2? > gcc/ > > PR target/121208 > * config/i386/i386.cc (ix86_tls_get_addr): Issue an error for > -mtls-dialect=gnu with no_caller_saved_registers attribute and > suggest -mtls-dialect=gnu2. > > gcc/testsuite/ > > PR target/121208 > * gcc.target/i386/pr121208-1a.c: New test. > * gcc.target/i386/pr121208-1b.c: Likewise. > * gcc.target/i386/pr121208-2a.c: Likewise. > * gcc.target/i386/pr121208-2b.c: Likewise. > * gcc.target/i386/pr121208-3a.c: Likewise. > * gcc.target/i386/pr121208-3b.c: Likewise. > > Signed-off-by: H.J. Lu <hjl.to...@gmail.com> > --- > gcc/config/i386/i386.cc | 38 +++++++++++++++++++++ > gcc/testsuite/gcc.target/i386/pr121208-1a.c | 15 ++++++++ > gcc/testsuite/gcc.target/i386/pr121208-1b.c | 4 +++ > gcc/testsuite/gcc.target/i386/pr121208-2a.c | 17 +++++++++ > gcc/testsuite/gcc.target/i386/pr121208-2b.c | 4 +++ > gcc/testsuite/gcc.target/i386/pr121208-3a.c | 17 +++++++++ > gcc/testsuite/gcc.target/i386/pr121208-3b.c | 4 +++ > 7 files changed, 99 insertions(+) > create mode 100644 gcc/testsuite/gcc.target/i386/pr121208-1a.c > create mode 100644 gcc/testsuite/gcc.target/i386/pr121208-1b.c > create mode 100644 gcc/testsuite/gcc.target/i386/pr121208-2a.c > create mode 100644 gcc/testsuite/gcc.target/i386/pr121208-2b.c > create mode 100644 gcc/testsuite/gcc.target/i386/pr121208-3a.c > create mode 100644 gcc/testsuite/gcc.target/i386/pr121208-3b.c > > diff --git a/gcc/config/i386/i386.cc b/gcc/config/i386/i386.cc > index 4682db85ce4..7a2037ab6b4 100644 > --- a/gcc/config/i386/i386.cc > +++ b/gcc/config/i386/i386.cc > @@ -12442,6 +12442,44 @@ static GTY(()) rtx ix86_tls_symbol; > static rtx > ix86_tls_get_addr (void) > { > + if (cfun->machine->call_saved_registers > + == TYPE_NO_CALLER_SAVED_REGISTERS) > + { > + /* On x86-64, __tls_get_addr is a normal function which doesn't > + preserve vector registers. On i386, ___tls_get_addr preserve > + vector registers only with the commit: > + > + 848f0e46f0 i386: Update ___tls_get_addr to preserve vector registers > + > + which fixed: > + > + https://sourceware.org/bugzilla/show_bug.cgi?id=32996 > + > + -mtls-dialect=gnu2 should be used instead with a fixed glibc > + for > + > + https://sourceware.org/bugzilla/show_bug.cgi?id=31372 > + > + with the commit: > + > + 0aac205a81 x86: Update _dl_tlsdesc_dynamic to preserve caller-saved > registers The comment here does not need to be so verbose. Uros. > + > + */ > + if (cfun->machine->func_type != TYPE_NORMAL) > + error (cfun->machine->func_type == TYPE_EXCEPTION > + ? G_("%<-mtls-dialect=gnu2%> must be used with an" > + " exception service routine") > + : G_("%<-mtls-dialect=gnu2%> must be used with an" > + " interrupt service routine")); > + else > + error (G_("%<-mtls-dialect=gnu2%> must be used with a function" > + " with the %<no_caller_saved_registers%> attribute")); > + /* Don't issue the same error twice. */ > + cfun->machine->func_type = TYPE_NORMAL; > + cfun->machine->call_saved_registers > + = TYPE_DEFAULT_CALL_SAVED_REGISTERS; > + } > + > if (!ix86_tls_symbol) > { > const char *sym > diff --git a/gcc/testsuite/gcc.target/i386/pr121208-1a.c > b/gcc/testsuite/gcc.target/i386/pr121208-1a.c > new file mode 100644 > index 00000000000..ac851cb50d8 > --- /dev/null > +++ b/gcc/testsuite/gcc.target/i386/pr121208-1a.c > @@ -0,0 +1,15 @@ > +/* { dg-do compile { target *-*-linux* } } */ > +/* { dg-options "-O2 -fPIC -mtls-dialect=gnu" } */ > + > +extern __thread int bar; > +extern void func (void); > + > +__attribute__((no_caller_saved_registers)) > +void > +foo (int error) > +{ > + bar = 1; /* { dg-error -mtls-dialect=gnu2 } */ > + if (error == 0) > + func (); > + bar = 0; > +} > diff --git a/gcc/testsuite/gcc.target/i386/pr121208-1b.c > b/gcc/testsuite/gcc.target/i386/pr121208-1b.c > new file mode 100644 > index 00000000000..b97ac715c65 > --- /dev/null > +++ b/gcc/testsuite/gcc.target/i386/pr121208-1b.c > @@ -0,0 +1,4 @@ > +/* { dg-do compile { target *-*-linux* } } */ > +/* { dg-options "-O2 -fPIC -mtls-dialect=gnu2" } */ > + > +#include "pr121208-1a.c" > diff --git a/gcc/testsuite/gcc.target/i386/pr121208-2a.c > b/gcc/testsuite/gcc.target/i386/pr121208-2a.c > new file mode 100644 > index 00000000000..c1891ae322c > --- /dev/null > +++ b/gcc/testsuite/gcc.target/i386/pr121208-2a.c > @@ -0,0 +1,17 @@ > +/* { dg-do compile { target *-*-linux* } } */ > +/* { dg-options "-O2 -fPIC -mtls-dialect=gnu" } */ > + > +typedef unsigned int uword_t __attribute__ ((mode (__word__))); > +extern __thread int bar; > +extern void func (void); > + > +__attribute__((target("general-regs-only"))) > +__attribute__((interrupt)) > +void > +foo (void *frame, uword_t error) > +{ > + bar = 1; /* { dg-error -mtls-dialect=gnu2 } */ > + if (error == 0) > + func (); > + bar = 0; > +} > diff --git a/gcc/testsuite/gcc.target/i386/pr121208-2b.c > b/gcc/testsuite/gcc.target/i386/pr121208-2b.c > new file mode 100644 > index 00000000000..269b120f990 > --- /dev/null > +++ b/gcc/testsuite/gcc.target/i386/pr121208-2b.c > @@ -0,0 +1,4 @@ > +/* { dg-do compile { target *-*-linux* } } */ > +/* { dg-options "-O2 -fPIC -mtls-dialect=gnu2" } */ > + > +#include "pr121208-2a.c" > diff --git a/gcc/testsuite/gcc.target/i386/pr121208-3a.c > b/gcc/testsuite/gcc.target/i386/pr121208-3a.c > new file mode 100644 > index 00000000000..26fe6870155 > --- /dev/null > +++ b/gcc/testsuite/gcc.target/i386/pr121208-3a.c > @@ -0,0 +1,17 @@ > +/* { dg-do compile { target *-*-linux* } } */ > +/* { dg-options "-O2 -fPIC -mtls-dialect=gnu" } */ > + > +typedef unsigned int uword_t __attribute__ ((mode (__word__))); > +extern __thread int bar; > +extern void func (void); > + > +__attribute__((target("general-regs-only"))) > +__attribute__((interrupt)) > +void > +foo (void *frame) > +{ > + bar = 1; /* { dg-error -mtls-dialect=gnu2 } */ > + if (frame == 0) > + func (); > + bar = 0; > +} > diff --git a/gcc/testsuite/gcc.target/i386/pr121208-3b.c > b/gcc/testsuite/gcc.target/i386/pr121208-3b.c > new file mode 100644 > index 00000000000..b672d751d7f > --- /dev/null > +++ b/gcc/testsuite/gcc.target/i386/pr121208-3b.c > @@ -0,0 +1,4 @@ > +/* { dg-do compile { target *-*-linux* } } */ > +/* { dg-options "-O2 -fPIC -mtls-dialect=gnu2" } */ > + > +#include "pr121208-3a.c" > -- > 2.50.1 >
