https://gcc.gnu.org/g:4db9571488eb9f39f0b06435a8642a4f11e82dcf
commit r16-3188-g4db9571488eb9f39f0b06435a8642a4f11e82dcf
Author: Iain Sandoe <i...@sandoe.co.uk>
Date: Sat Aug 9 08:19:08 2025 +0100
Darwin: Handle string constants specially when asan is enabled.
The Darwin ABI uses a different section for string constants when
address sanitizing is enabled. This adds defintions of the asan-
specific sections and switches string constants to the correct
section.
It also makes the string constant symbols linker-visible when
asan is enabled, but not otherwise.
gcc/ChangeLog:
* config/darwin-sections.def (asan_string_section,
asan_globals_section, asan_liveness_section): New.
* config/darwin.cc (objc_method_decl): Use asan sections
when asan is enabled.
(darwin_encode_section_info): Alter string constant
linker visibility depending on asan.
(machopic_select_section): Use the asan sections when
asan is enabled.
gcc/testsuite/ChangeLog:
* gcc.dg/torture/darwin-cfstring-3.c: Adjust for amended
string labels.
* g++.dg/torture/darwin-cfstring-3.C: Likewise.
Signed-off-by: Iain Sandoe <i...@sandoe.co.uk>
Diff:
---
gcc/config/darwin-sections.def | 7 +++++
gcc/config/darwin.cc | 39 ++++++++++++++++++++----
gcc/testsuite/g++.dg/torture/darwin-cfstring-3.C | 8 ++---
gcc/testsuite/gcc.dg/torture/darwin-cfstring-3.c | 8 ++---
4 files changed, 48 insertions(+), 14 deletions(-)
diff --git a/gcc/config/darwin-sections.def b/gcc/config/darwin-sections.def
index 44adcc6062db..76587c268cef 100644
--- a/gcc/config/darwin-sections.def
+++ b/gcc/config/darwin-sections.def
@@ -215,3 +215,10 @@ DEF_SECTION (objc2_method_names_section, 0,
DEF_SECTION (objc2_method_types_section, 0,
".section __TEXT, __objc_methtype, cstring_literals", 1)
+
+/* ASAN sections. */
+
+DEF_SECTION (asan_string_section, 0, ".section __TEXT, __asan_cstring", 0)
+DEF_SECTION (asan_globals_section, 0, ".section __DATA, __asan_globals", 0)
+DEF_SECTION (asan_liveness_section, 0,
+ ".section __DATA,__asan_liveness,regular,live_support", 0)
diff --git a/gcc/config/darwin.cc b/gcc/config/darwin.cc
index 1724084b6287..75ac3560954b 100644
--- a/gcc/config/darwin.cc
+++ b/gcc/config/darwin.cc
@@ -49,6 +49,7 @@ along with GCC; see the file COPYING3. If not see
#include "optabs.h"
#include "flags.h"
#include "opts.h"
+#include "asan.h"
/* Fix and Continue.
@@ -1303,8 +1304,9 @@ darwin_encode_section_info (tree decl, rtx rtl, int first)
bool is_str = TREE_CODE (decl) == STRING_CST;
rtx sym_ref = XEXP (rtl, 0);
- /* If this is a string cst or not anchored we have nothing to do. */
- if (is_str || !SYMBOL_REF_HAS_BLOCK_INFO_P (sym_ref))
+ /* Unless this is a string cst or we are in an anchored section we have
+ nothing more to do here. */
+ if (!is_str && !SYMBOL_REF_HAS_BLOCK_INFO_P (sym_ref))
return;
tree sym_decl = SYMBOL_REF_DECL (sym_ref);
@@ -1312,9 +1314,18 @@ darwin_encode_section_info (tree decl, rtx rtl, int
first)
gcc_checking_assert (strncmp ("*lC", name, 3) == 0);
char *buf;
- /* Lets identify anchored constants with a different prefix, for the
- sake of inspection only. */
- buf = xasprintf ("*LaC%s", &name[3]);
+ if (is_str)
+ {
+ bool for_asan = (flag_sanitize & SANITIZE_ADDRESS)
+ && asan_protect_global (CONST_CAST_TREE (decl));
+ /* When we are generating code for sanitized strings, the string
+ internal symbols are made visible in the object. */
+ buf = xasprintf ("*%c.str.%s", for_asan ? 'l' : 'L', &name[3]);
+ }
+ else
+ /* Lets identify anchored constants with a different prefix, for the
+ sake of inspection only. */
+ buf = xasprintf ("*LaC%s", &name[3]);
if (sym_decl)
DECL_NAME (sym_decl) = get_identifier (buf);
XSTR (sym_ref, 0) = ggc_strdup (buf);
@@ -1706,6 +1717,17 @@ machopic_select_section (tree decl,
ro = TREE_READONLY (decl) || TREE_CONSTANT (decl) ;
+ /* Trump categorize_decl_for_section () for ASAN stuff - the Darwin
+ categorisations are special. */
+ if (flag_sanitize & SANITIZE_ADDRESS)
+ {
+ if (TREE_CODE (decl) == STRING_CST
+ && asan_protect_global (CONST_CAST_TREE (decl)))
+ {
+ return darwin_sections[asan_string_section];
+ }
+ }
+
switch (categorize_decl_for_section (decl, reloc))
{
case SECCAT_TEXT:
@@ -1722,7 +1744,12 @@ machopic_select_section (tree decl,
break;
case SECCAT_RODATA_MERGE_STR_INIT:
- base_section = darwin_mergeable_string_section (DECL_INITIAL (decl),
align);
+ if ((flag_sanitize & SANITIZE_ADDRESS)
+ && asan_protect_global (CONST_CAST_TREE (decl)))
+ /* or !flag_merge_constants */
+ return darwin_sections[asan_string_section];
+ else
+ return darwin_mergeable_string_section (DECL_INITIAL (decl), align);
break;
case SECCAT_RODATA_MERGE_CONST:
diff --git a/gcc/testsuite/g++.dg/torture/darwin-cfstring-3.C
b/gcc/testsuite/g++.dg/torture/darwin-cfstring-3.C
index ee4b385b17fa..4be3a2526c3e 100644
--- a/gcc/testsuite/g++.dg/torture/darwin-cfstring-3.C
+++ b/gcc/testsuite/g++.dg/torture/darwin-cfstring-3.C
@@ -24,7 +24,7 @@ void foo(void) {
s0 = s1;
}
-/* { dg-final { scan-assembler "\\.long\[
\\t\]+___CFConstantStringClassReference\n\[ \\t\]*\\.long\[ \\t\]+1992\n\[
\\t\]*\\.long\[ \\t\]+\[lL\]C.*\n\[ \\t\]*\\.long\[ \\t\]+4\n" { target {
*-*-darwin* && { ! lp64 } } } } } */
-/* { dg-final { scan-assembler "\\.long\[
\\t\]+___CFConstantStringClassReference\n\[ \\t\]*\\.long\[ \\t\]+1992\n\[
\\t\]*\\.long\[ \\t\]+\[lL\]C.*\n\[ \\t\]*\\.long\[ \\t\]+10\n" { target {
*-*-darwin* && { ! lp64 } } } } } */
-/* { dg-final { scan-assembler
".quad\t___CFConstantStringClassReference\n\t.long\t1992\n\t.space
4\n\t.quad\t.*\n\t.quad\t4\n" { target { *-*-darwin* && { lp64 } } } } } */
-/* { dg-final { scan-assembler
".quad\t___CFConstantStringClassReference\n\t.long\t1992\n\t.space
4\n\t.quad\t.*\n\t.quad\t10\n" { target { *-*-darwin* && { lp64 } } } } } */
+/* { dg-final { scan-assembler "\\.long\[
\\t\]+___CFConstantStringClassReference\n\[ \\t\]*\\.long\[ \\t\]+1992\n\[
\\t\]*\\.long\[ \\t\]+L\.str\..*\n\[ \\t\]*\\.long\[ \\t\]+4\n" { target {
*-*-darwin* && { ! lp64 } } } } } */
+/* { dg-final { scan-assembler "\\.long\[
\\t\]+___CFConstantStringClassReference\n\[ \\t\]*\\.long\[ \\t\]+1992\n\[
\\t\]*\\.long\[ \\t\]+L\.str\..*\n\[ \\t\]*\\.long\[ \\t\]+10\n" { target {
*-*-darwin* && { ! lp64 } } } } } */
+/* { dg-final { scan-assembler
".quad\t___CFConstantStringClassReference\n\t.long\t1992\n\t.space
4\n\t.quad\tL\.str\..*\n\t.quad\t4\n" { target { *-*-darwin* && { lp64 } } } }
} */
+/* { dg-final { scan-assembler
".quad\t___CFConstantStringClassReference\n\t.long\t1992\n\t.space
4\n\t.quad\tL\.str\..*\n\t.quad\t10\n" { target { *-*-darwin* && { lp64 } } }
} } */
diff --git a/gcc/testsuite/gcc.dg/torture/darwin-cfstring-3.c
b/gcc/testsuite/gcc.dg/torture/darwin-cfstring-3.c
index ee4b385b17fa..4be3a2526c3e 100644
--- a/gcc/testsuite/gcc.dg/torture/darwin-cfstring-3.c
+++ b/gcc/testsuite/gcc.dg/torture/darwin-cfstring-3.c
@@ -24,7 +24,7 @@ void foo(void) {
s0 = s1;
}
-/* { dg-final { scan-assembler "\\.long\[
\\t\]+___CFConstantStringClassReference\n\[ \\t\]*\\.long\[ \\t\]+1992\n\[
\\t\]*\\.long\[ \\t\]+\[lL\]C.*\n\[ \\t\]*\\.long\[ \\t\]+4\n" { target {
*-*-darwin* && { ! lp64 } } } } } */
-/* { dg-final { scan-assembler "\\.long\[
\\t\]+___CFConstantStringClassReference\n\[ \\t\]*\\.long\[ \\t\]+1992\n\[
\\t\]*\\.long\[ \\t\]+\[lL\]C.*\n\[ \\t\]*\\.long\[ \\t\]+10\n" { target {
*-*-darwin* && { ! lp64 } } } } } */
-/* { dg-final { scan-assembler
".quad\t___CFConstantStringClassReference\n\t.long\t1992\n\t.space
4\n\t.quad\t.*\n\t.quad\t4\n" { target { *-*-darwin* && { lp64 } } } } } */
-/* { dg-final { scan-assembler
".quad\t___CFConstantStringClassReference\n\t.long\t1992\n\t.space
4\n\t.quad\t.*\n\t.quad\t10\n" { target { *-*-darwin* && { lp64 } } } } } */
+/* { dg-final { scan-assembler "\\.long\[
\\t\]+___CFConstantStringClassReference\n\[ \\t\]*\\.long\[ \\t\]+1992\n\[
\\t\]*\\.long\[ \\t\]+L\.str\..*\n\[ \\t\]*\\.long\[ \\t\]+4\n" { target {
*-*-darwin* && { ! lp64 } } } } } */
+/* { dg-final { scan-assembler "\\.long\[
\\t\]+___CFConstantStringClassReference\n\[ \\t\]*\\.long\[ \\t\]+1992\n\[
\\t\]*\\.long\[ \\t\]+L\.str\..*\n\[ \\t\]*\\.long\[ \\t\]+10\n" { target {
*-*-darwin* && { ! lp64 } } } } } */
+/* { dg-final { scan-assembler
".quad\t___CFConstantStringClassReference\n\t.long\t1992\n\t.space
4\n\t.quad\tL\.str\..*\n\t.quad\t4\n" { target { *-*-darwin* && { lp64 } } } }
} */
+/* { dg-final { scan-assembler
".quad\t___CFConstantStringClassReference\n\t.long\t1992\n\t.space
4\n\t.quad\tL\.str\..*\n\t.quad\t10\n" { target { *-*-darwin* && { lp64 } } }
} } */
