https://gcc.gnu.org/g:3777a0b41f9fdcbb5fde4bdfce06031805cebc33
commit r16-5965-g3777a0b41f9fdcbb5fde4bdfce06031805cebc33 Author: Eric Botcazou <[email protected]> Date: Mon Dec 8 17:47:56 2025 +0100 MinGW: Fix native TLS bug with -fdata-sections The problem comes from a quirk of the GNU PE-COFF linker, which wants to make sure that .tls$ZZZ is laid out last among the TLS sections, but first globs all .tls$* sections together. The solution matches Clang's output. gcc/ PR target/80881 * config/mingw/winnt.cc (mingw_pe_unique_section): Put two dollar signs for TLS sections after the prefix. (mingw_pe_asm_named_section): Deal with all TLS sections uniformly. gcc/testsuite/ * gcc.dg/tls/data-sections-1.c: New test. Diff: --- gcc/config/mingw/winnt.cc | 10 ++++++---- gcc/testsuite/gcc.dg/tls/data-sections-1.c | 14 ++++++++++++++ 2 files changed, 20 insertions(+), 4 deletions(-) diff --git a/gcc/config/mingw/winnt.cc b/gcc/config/mingw/winnt.cc index b51fd8e9cc6a..fe2fb4cb267f 100644 --- a/gcc/config/mingw/winnt.cc +++ b/gcc/config/mingw/winnt.cc @@ -446,8 +446,11 @@ mingw_pe_unique_section (tree decl, int reloc) prefix = ".text$"; else if (decl_readonly_section (decl, reloc)) prefix = ".rdata$"; + /* Note that we need two dollar signs for TLS sections + because they need to be ASCII-sorted before .tls$ZZZ + to be properly laid out by the GNU linker. */ else if (DECL_THREAD_LOCAL_P (decl)) - prefix = ".tls$"; + prefix = ".tls$$"; else prefix = ".data$"; len = strlen (name) + strlen (prefix); @@ -522,9 +525,6 @@ mingw_pe_asm_named_section (const char *name, unsigned int flags, *f++ = 'e'; #endif - if (strcmp (name, ".tls$") == 0) - *f++ = 'd'; - if ((flags & (SECTION_CODE | SECTION_WRITE)) == 0) /* readonly data */ { @@ -533,6 +533,8 @@ mingw_pe_asm_named_section (const char *name, unsigned int flags, } else { + if (startswith (name, ".tls$")) + *f++ = 'd'; if (flags & SECTION_CODE) *f++ = 'x'; if (flags & SECTION_WRITE) diff --git a/gcc/testsuite/gcc.dg/tls/data-sections-1.c b/gcc/testsuite/gcc.dg/tls/data-sections-1.c new file mode 100644 index 000000000000..c829256b0162 --- /dev/null +++ b/gcc/testsuite/gcc.dg/tls/data-sections-1.c @@ -0,0 +1,14 @@ +/* { dg-do run } */ +/* { dg-require-effective-target tls_runtime } */ +/* { dg-options "-fdata-sections" } */ +/* { dg-add-options tls } */ + +__thread int i = 1; + +int main (void) +{ + if (i != 1) + __builtin_abort (); + + return 0; +}
