From 34ce7f7a9a64dd69dd6a77dfd4a77406c3c71014 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Cl=C3=A9ment=20Chigot?= Date: Thu, 12 Aug 2021 13:17:15 -0400 Subject: [PATCH] aix: 64 bit AIX TLS libpthread dependency. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 64bit XCOFF files will generated TLS access, with local-exec or global-exec models, by an access to R13. Thus, there isn't any reference to a TLS symbol. The problem is that it allows programs with TLS to be compiled and linked even without -pthread. Most of the time, it will result in a segfault when trying to access a TLS variable. But sometimes, it might create a memory corruption. This patch forces a reference to __tls_get_addr() to ensure link will fail without -pthread. gcc/ChangeLog: 2021-08-11 Clément Chigot * config/rs6000/rs6000.c (xcoff_tls_exec_model_detected): New. (rs6000_legitimize_tls_address_aix): Use it. (rs6000_xcoff_file_end): Add ".ref __tls_get_addr" when xcoff_tls_exec_model_detected is true. --- gcc/config/rs6000/rs6000.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c index 60f406a4ff6..e073b26b430 100644 --- a/gcc/config/rs6000/rs6000.c +++ b/gcc/config/rs6000/rs6000.c @@ -127,6 +127,9 @@ scalar_int_mode rs6000_pmode; bool rs6000_passes_ieee128 = false; #endif +/* Track use of r13 in 64bit AIX TLS. */ +static bool xcoff_tls_exec_model_detected = false; + /* Generate the manged name (i.e. U10__float128) used in GCC 8.1, and not the name used in current releases (i.e. u9__ieee128). */ static bool ieee128_mangling_gcc_8_1; @@ -9397,7 +9400,10 @@ rs6000_legitimize_tls_address_aix (rtx addr, enum tls_model model) emit_insn (gen_tls_get_tpointer (tlsreg)); } else - tlsreg = gen_rtx_REG (DImode, 13); + { + tlsreg = gen_rtx_REG (DImode, 13); + xcoff_tls_exec_model_detected = true; + } /* Load the TOC value into temporary register. */ tmpreg = gen_reg_rtx (Pmode); @@ -21122,6 +21128,12 @@ rs6000_xcoff_file_end (void) fputs (TARGET_32BIT ? "\t.long _section_.text\n" : "\t.llong _section_.text\n", asm_out_file); + + if (xcoff_tls_exec_model_detected) + { + /* Add a .ref to __tls_get_addr to force libpthread dependency. */ + fputs ("\t.extern __tls_get_addr\n\t.ref __tls_get_addr\n", asm_out_file); + } } struct declare_alias_data