| Message ID | 20201115220354.zeltrrhtnqfpbj42@jozef-acer-manjaro |
|---|---|
| State | New |
| Headers | show |
| Series | [1/3] Fix "noinit" attribute being ignored for -O0 and -fdata-sections | expand |
On 11/15/20 3:03 PM, Jozef Lawrynowicz wrote: > Variables with the "noinit" attribute are ignored at -O0 because they > are treated like a regular bss variable and placed in the .bss section. > > With -fdata-sections they are ignored because they are not handled in > resolve_unique_section. > > Successfully regtested for arm-none-eabi. > > Ok for trunk? > > 0001-Fix-noinit-attribute-being-ignored-for-O0-and-fdata-.patch > > From d501b36fc92f1506427836ded69997cc576beda4 Mon Sep 17 00:00:00 2001 > From: Jozef Lawrynowicz <jozef.l@mittosystems.com> > Date: Sun, 15 Nov 2020 21:43:22 +0000 > Subject: [PATCH 1/3] Fix "noinit" attribute being ignored for -O0 and > -fdata-sections > > Variables with the "noinit" attribute are ignored at -O0 because they > are treated like a regular bss variable and placed in the .bss section. > > With -fdata-sections they are ignored because they are not handled in > resolve_unique_section. > > gcc/ChangeLog: > > * tree.h (DECL_NOINIT_P): Define. > * varasm.c (DECL_NOINIT_P): Check DECL_NOINIT_P before using > unnamed bss/lcomm sections for bss_initializer variables. > (default_elf_select_section): Use DECL_NOINIT_P instead of > looking up attribute for .noinit section selection. > (default_unique_section): Check DECL_NOINIT_P for .noinit > section selection. > > gcc/testsuite/ChangeLog: > > * gcc.c-torture/execute/noinit-attribute.c: Don't override > optimization options set by torture test harness. > * lib/target-supports.exp (check_effective_target_noinit): Adjust > comment formatting. OK jeff
diff --git a/gcc/testsuite/gcc.c-torture/execute/noinit-attribute.c b/gcc/testsuite/gcc.c-torture/execute/noinit-attribute.c index 20a2a452e79..c8fa22bf38b 100644 --- a/gcc/testsuite/gcc.c-torture/execute/noinit-attribute.c +++ b/gcc/testsuite/gcc.c-torture/execute/noinit-attribute.c @@ -1,6 +1,6 @@ /* { dg-do run } */ /* { dg-require-effective-target noinit } */ -/* { dg-options "-O2" } */ +/* { dg-options "-Wattributes" } */ /* { dg-skip-if "data LMA != VMA" { msp430-*-* } { "-mlarge" } } */ /* This test checks that noinit data is handled correctly. diff --git a/gcc/testsuite/lib/target-supports.exp b/gcc/testsuite/lib/target-supports.exp index 60ebbb39f9d..49c65b50109 100644 --- a/gcc/testsuite/lib/target-supports.exp +++ b/gcc/testsuite/lib/target-supports.exp @@ -368,7 +368,7 @@ proc check_weak_override_available { } { return [check_weak_available] } -# The noinit attribute is only supported by some targets. +# The "noinit" attribute is only supported by some targets. # This proc returns 1 if it's supported, 0 if it's not. proc check_effective_target_noinit { } { diff --git a/gcc/tree.h b/gcc/tree.h index f8f0a606439..f342731ae59 100644 --- a/gcc/tree.h +++ b/gcc/tree.h @@ -2659,6 +2659,13 @@ extern tree vector_element_bits_tree (const_tree); #define DECL_PRESERVE_P(DECL) \ DECL_COMMON_CHECK (DECL)->decl_common.preserve_flag +/* Nonzero for a decl that is decorated with the "noinit" attribute. + decls with this attribute are placed into the ".noinit" section, so they are + not initialized by the target's startup code. */ +#define DECL_NOINIT_P(DECL) \ + (DECL_P (DECL) \ + && (lookup_attribute ("noinit", DECL_ATTRIBUTES (DECL)) != NULL_TREE)) + /* For function local variables of COMPLEX and VECTOR types, indicates that the variable is not aliased, and that all modifications to the variable have been adjusted so that diff --git a/gcc/varasm.c b/gcc/varasm.c index 435c7b348a5..3c902059069 100644 --- a/gcc/varasm.c +++ b/gcc/varasm.c @@ -1208,6 +1208,7 @@ get_variable_section (tree decl, bool prefer_noswitch_p) if (ADDR_SPACE_GENERIC_P (as) && !DECL_THREAD_LOCAL_P (decl) + && !DECL_NOINIT_P (decl) && !(prefer_noswitch_p && targetm.have_switchable_bss_sections) && bss_initializer_p (decl)) { @@ -7009,13 +7010,11 @@ default_elf_select_section (tree decl, int reloc, sname = ".tdata"; break; case SECCAT_BSS: - if (DECL_P (decl) - && lookup_attribute ("noinit", DECL_ATTRIBUTES (decl)) != NULL_TREE) + if (DECL_P (decl) && DECL_NOINIT_P (decl)) { sname = ".noinit"; break; } - if (bss_section) return bss_section; sname = ".bss"; @@ -7078,6 +7077,11 @@ default_unique_section (tree decl, int reloc) prefix = one_only ? ".s" : ".sdata"; break; case SECCAT_BSS: + if (DECL_P (decl) && DECL_NOINIT_P (decl)) + { + prefix = one_only ? ".n" : ".noinit"; + break; + } prefix = one_only ? ".b" : ".bss"; break; case SECCAT_SBSS:
Variables with the "noinit" attribute are ignored at -O0 because they are treated like a regular bss variable and placed in the .bss section. With -fdata-sections they are ignored because they are not handled in resolve_unique_section. Successfully regtested for arm-none-eabi. Ok for trunk? From d501b36fc92f1506427836ded69997cc576beda4 Mon Sep 17 00:00:00 2001 From: Jozef Lawrynowicz <jozef.l@mittosystems.com> Date: Sun, 15 Nov 2020 21:43:22 +0000 Subject: [PATCH 1/3] Fix "noinit" attribute being ignored for -O0 and -fdata-sections Variables with the "noinit" attribute are ignored at -O0 because they are treated like a regular bss variable and placed in the .bss section. With -fdata-sections they are ignored because they are not handled in resolve_unique_section. gcc/ChangeLog: * tree.h (DECL_NOINIT_P): Define. * varasm.c (DECL_NOINIT_P): Check DECL_NOINIT_P before using unnamed bss/lcomm sections for bss_initializer variables. (default_elf_select_section): Use DECL_NOINIT_P instead of looking up attribute for .noinit section selection. (default_unique_section): Check DECL_NOINIT_P for .noinit section selection. gcc/testsuite/ChangeLog: * gcc.c-torture/execute/noinit-attribute.c: Don't override optimization options set by torture test harness. * lib/target-supports.exp (check_effective_target_noinit): Adjust comment formatting. --- gcc/testsuite/gcc.c-torture/execute/noinit-attribute.c | 2 +- gcc/testsuite/lib/target-supports.exp | 2 +- gcc/tree.h | 7 +++++++ gcc/varasm.c | 10 +++++++--- 4 files changed, 16 insertions(+), 5 deletions(-)