* [PATCH v2 0/2] Implement indirect external access
@ 2021-06-24 13:47 H.J. Lu
2021-06-24 13:47 ` [PATCH v2 1/2] Add -f[no-]direct-extern-access H.J. Lu
2021-06-24 13:47 ` [PATCH v2 2/2] Add TARGET_ASM_EMIT_GNU_PROPERTY_NOTE H.J. Lu
0 siblings, 2 replies; 3+ messages in thread
From: H.J. Lu @ 2021-06-24 13:47 UTC (permalink / raw)
To: gcc-patches; +Cc: Uros Bizjak, Jakub Jelinek, Richard Biener
Changes in the v2 patch.
1. Rename the option to -fdirect-extern-access.
---
On systems with copy relocation:
* A copy in executable is created for the definition in a shared library
at run-time by ld.so.
* The copy is referenced by executable and shared libraries.
* Executable can access the copy directly.
Issues are:
* Overhead of a copy, time and space, may be visible at run-time.
* Read-only data in the shared library becomes read-write copy in
executable at run-time.
* Local access to data with the STV_PROTECTED visibility in the shared
library must use GOT.
On systems without function descriptor, function pointers vary depending
on where and how the functions are defined.
* If the function is defined in executable, it can be the address of
function body.
* If the function, including the function with STV_PROTECTED visibility,
is defined in the shared library, it can be the address of the PLT entry
in executable or shared library.
Issues are:
* The address of function body may not be used as its function pointer.
* ld.so needs to search loaded shared libraries for the function pointer
of the function with STV_PROTECTED visibility.
Here is a proposal to remove copy relocation and use canonical function
pointer:
1. Accesses, including in PIE and non-PIE, to undefined symbols must
use GOT.
a. Linker may optimize out GOT access if the data is defined in PIE or
non-PIE.
2. Read-only data in the shared library remain read-only at run-time
3. Address of global data with the STV_PROTECTED visibility in the shared
library is the address of data body.
a. Can use IP-relative access.
b. May need GOT without IP-relative access.
4. For systems without function descriptor,
a. All global function pointers of undefined functions in PIE and
non-PIE must use GOT. Linker may optimize out GOT access if the
function is defined in PIE or non-PIE.
b. Function pointer of functions with the STV_PROTECTED visibility in
executable and shared library is the address of function body.
i. Can use IP-relative access.
ii. May need GOT without IP-relative access.
iii. Branches to undefined functions may use PLT.
5. Single global definition marker:
Add GNU_PROPERTY_1_NEEDED:
#define GNU_PROPERTY_1_NEEDED GNU_PROPERTY_UINT32_OR_LO
to indicate the needed properties by the object file.
Add GNU_PROPERTY_1_NEEDED_INDIRECT_EXTERN_ACCESS:
#define GNU_PROPERTY_1_NEEDED_INDIRECT_EXTERN_ACCESS (1U << 0)
to indicate that the object file requires canonical function pointers and
cannot be used with copy relocation. This bit should be cleared in
executable when there are non-GOT or non-PLT relocations in relocatable
input files without this bit set.
a. Protected symbol access within the shared library can be treated as
local.
b. Copy relocation should be disallowed at link-time and run-time.
c. GOT function pointer reference is required at link-time and run-time.
The indirect external access marker can be used in the following ways:
1. Linker can decide the best way to resolve a relocation against a
protected symbol before seeing all relocations against the symbol.
2. Dynamic linker can decide if it is an error to have a copy relocation
in executable against the protected symbol in a shared library by checking
if the shared library is built with -fno-direct-extern-access.
Add a compiler option, -fdirect-extern-access. -fdirect-extern-access is
the default. With -fno-direct-extern-access:
1. Always to use GOT to access undefined symbols, including in PIE and
non-PIE. This is safe to do and does not break the ABI.
2. In executable and shared library, for symbols with the STV_PROTECTED
visibility:
a. The address of data symbol is the address of data body.
b. For systems without function descriptor, the function pointer is
the address of function body.
These break the ABI and resulting shared libraries may not be compatible
with executables which are not compiled with -fno-direct-extern-access.
3. Generate an indirect external access marker in relocatable objects if
supported by linker.
H.J. Lu (2):
Add -f[no-]direct-extern-access
Add TARGET_ASM_EMIT_GNU_PROPERTY_NOTE
gcc/common.opt | 4 ++
gcc/config.in | 6 +++
gcc/config/i386/gnu-property.c | 31 -------------
gcc/config/i386/i386-protos.h | 2 +-
gcc/config/i386/i386.c | 52 ++++++++++++++++------
gcc/configure | 24 ++++++++++
gcc/configure.ac | 20 +++++++++
gcc/doc/invoke.texi | 13 ++++++
gcc/doc/tm.texi | 5 +++
gcc/doc/tm.texi.in | 2 +
gcc/output.h | 2 +
gcc/target.def | 8 ++++
gcc/testsuite/g++.dg/pr35513-1.C | 25 +++++++++++
gcc/testsuite/g++.dg/pr35513-2.C | 53 +++++++++++++++++++++++
gcc/testsuite/gcc.target/i386/pr35513-1.c | 16 +++++++
gcc/testsuite/gcc.target/i386/pr35513-2.c | 15 +++++++
gcc/testsuite/gcc.target/i386/pr35513-3.c | 15 +++++++
gcc/testsuite/gcc.target/i386/pr35513-4.c | 15 +++++++
gcc/testsuite/gcc.target/i386/pr35513-5.c | 15 +++++++
gcc/testsuite/gcc.target/i386/pr35513-6.c | 14 ++++++
gcc/testsuite/gcc.target/i386/pr35513-7.c | 15 +++++++
gcc/testsuite/gcc.target/i386/pr35513-8.c | 41 ++++++++++++++++++
gcc/toplev.c | 3 ++
gcc/varasm.c | 47 ++++++++++++++++++++
24 files changed, 397 insertions(+), 46 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/pr35513-1.C
create mode 100644 gcc/testsuite/g++.dg/pr35513-2.C
create mode 100644 gcc/testsuite/gcc.target/i386/pr35513-1.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr35513-2.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr35513-3.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr35513-4.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr35513-5.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr35513-6.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr35513-7.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr35513-8.c
--
2.31.1
^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH v2 1/2] Add -f[no-]direct-extern-access
2021-06-24 13:47 [PATCH v2 0/2] Implement indirect external access H.J. Lu
@ 2021-06-24 13:47 ` H.J. Lu
2021-06-24 13:47 ` [PATCH v2 2/2] Add TARGET_ASM_EMIT_GNU_PROPERTY_NOTE H.J. Lu
1 sibling, 0 replies; 3+ messages in thread
From: H.J. Lu @ 2021-06-24 13:47 UTC (permalink / raw)
To: gcc-patches; +Cc: Uros Bizjak, Jakub Jelinek, Richard Biener
-fdirect-extern-access is the default. With -fno-direct-extern-access:
1. Always use GOT to access undefined data and function symbols,
including in PIE and non-PIE. These will avoid copy relocations
in executables. This is compatible with existing executables and
shared libraries.
2. In executable and shared library, bind symbols with the STV_PROTECTED
visibility locally:
a. The address of data symbol is the address of data body.
b. For systems without function descriptor, the function pointer is
the address of function body.
c. The resulting shared libraries may not be incompatible with
executables which have copy relocations on protected symbols.
3. Update asm_preferred_eh_data_format to properly select EH encoding
format with -fno-direct-extern-access.
4. Add ix86_reloc_rw_mask for TARGET_ASM_RELOC_RW_MASK to avoid copy
relocation with -fno-direct-extern-access.
gcc/
PR target/35513
PR target/100593
* common.opt: Add -fdirect-extern-access.
* config/i386/i386-protos.h (ix86_force_load_from_GOT_p): Add a
bool argument.
* config/i386/i386.c (ix86_force_load_from_GOT_p): Add a bool
argument to indicate call operand. Force non-call load
from GOT for -fno-direct-extern-access.
(legitimate_pic_address_disp_p): Avoid copy relocation in PIE
for -fno-direct-extern-access.
(ix86_print_operand): Pass true to ix86_force_load_from_GOT_p
for call operand.
(asm_preferred_eh_data_format): Use PC-relative format for
-fno-direct-extern-access to avoid copy relocation. Check
ptr_mode instead of TARGET_64BIT when selecting DW_EH_PE_sdata4.
(ix86_binds_local_p): Don't treat protected data as extern and
avoid copy relocation on common symbol with
-fno-direct-extern-access.
(ix86_reloc_rw_mask): New to avoid copy relocation for
-fno-direct-extern-access.
(TARGET_ASM_RELOC_RW_MASK): New.
* doc/invoke.texi: Document -f[no-]direct-extern-access.
gcc/testsuite/
PR target/35513
PR target/100593
* g++.dg/pr35513-1.C: New file.
* g++.dg/pr35513-2.C: Likewise.
* gcc.target/i386/pr35513-1.c: Likewise.
* gcc.target/i386/pr35513-2.c: Likewise.
* gcc.target/i386/pr35513-3.c: Likewise.
* gcc.target/i386/pr35513-4.c: Likewise.
* gcc.target/i386/pr35513-5.c: Likewise.
* gcc.target/i386/pr35513-6.c: Likewise.
* gcc.target/i386/pr35513-7.c: Likewise.
* gcc.target/i386/pr35513-8.c: Likewise.
---
gcc/common.opt | 4 ++
gcc/config/i386/i386-protos.h | 2 +-
gcc/config/i386/i386.c | 50 +++++++++++++++------
gcc/doc/invoke.texi | 13 ++++++
gcc/testsuite/g++.dg/pr35513-1.C | 25 +++++++++++
gcc/testsuite/g++.dg/pr35513-2.C | 53 +++++++++++++++++++++++
gcc/testsuite/gcc.target/i386/pr35513-1.c | 16 +++++++
gcc/testsuite/gcc.target/i386/pr35513-2.c | 15 +++++++
gcc/testsuite/gcc.target/i386/pr35513-3.c | 15 +++++++
gcc/testsuite/gcc.target/i386/pr35513-4.c | 15 +++++++
gcc/testsuite/gcc.target/i386/pr35513-5.c | 15 +++++++
gcc/testsuite/gcc.target/i386/pr35513-6.c | 14 ++++++
gcc/testsuite/gcc.target/i386/pr35513-7.c | 15 +++++++
gcc/testsuite/gcc.target/i386/pr35513-8.c | 41 ++++++++++++++++++
14 files changed, 278 insertions(+), 15 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/pr35513-1.C
create mode 100644 gcc/testsuite/g++.dg/pr35513-2.C
create mode 100644 gcc/testsuite/gcc.target/i386/pr35513-1.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr35513-2.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr35513-3.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr35513-4.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr35513-5.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr35513-6.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr35513-7.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr35513-8.c
diff --git a/gcc/common.opt b/gcc/common.opt
index a1353e06bdc..b4827f59cfa 100644
--- a/gcc/common.opt
+++ b/gcc/common.opt
@@ -1427,6 +1427,10 @@ fdiagnostics-minimum-margin-width=
Common Joined UInteger Var(diagnostics_minimum_margin_width) Init(6)
Set minimum width of left margin of source code when showing source.
+fdirect-extern-access
+Common Var(flag_direct_extern_access) Init(1) Optimization
+Do not use GOT to access external symbols.
+
fdisable-
Common Joined RejectNegative Var(common_deferred_options) Defer
-fdisable-[tree|rtl|ipa]-<pass>=range1+range2 Disable an optimization pass.
diff --git a/gcc/config/i386/i386-protos.h b/gcc/config/i386/i386-protos.h
index 65fc307dc7b..3f1bdd14e6d 100644
--- a/gcc/config/i386/i386-protos.h
+++ b/gcc/config/i386/i386-protos.h
@@ -77,7 +77,7 @@ extern bool ix86_expand_cmpstrn_or_cmpmem (rtx, rtx, rtx, rtx, rtx, bool);
extern bool constant_address_p (rtx);
extern bool legitimate_pic_operand_p (rtx);
extern bool legitimate_pic_address_disp_p (rtx);
-extern bool ix86_force_load_from_GOT_p (rtx);
+extern bool ix86_force_load_from_GOT_p (rtx, bool = false);
extern void print_reg (rtx, int, FILE*);
extern void ix86_print_operand (FILE *, rtx, int);
diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index 3d5883b8d0e..4ab85cc4fe0 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -10312,13 +10312,17 @@ darwin_local_data_pic (rtx disp)
}
/* True if the function symbol operand X should be loaded from GOT.
+ If CALL_P is true, X is a call operand.
+
+ NB: -fno-direct-extern-access doesn't force load from GOT for
+ call.
NB: In 32-bit mode, only non-PIC is allowed in inline assembly
statements, since a PIC register could not be available at the
call site. */
bool
-ix86_force_load_from_GOT_p (rtx x)
+ix86_force_load_from_GOT_p (rtx x, bool call_p)
{
return ((TARGET_64BIT || (!flag_pic && HAVE_AS_IX86_GOT32X))
&& !TARGET_PECOFF && !TARGET_MACHO
@@ -10326,11 +10330,12 @@ ix86_force_load_from_GOT_p (rtx x)
&& ix86_cmodel != CM_LARGE
&& ix86_cmodel != CM_LARGE_PIC
&& GET_CODE (x) == SYMBOL_REF
- && SYMBOL_REF_FUNCTION_P (x)
- && (!flag_plt
- || (SYMBOL_REF_DECL (x)
- && lookup_attribute ("noplt",
- DECL_ATTRIBUTES (SYMBOL_REF_DECL (x)))))
+ && ((!call_p && !flag_direct_extern_access)
+ || (SYMBOL_REF_FUNCTION_P (x)
+ && (!flag_plt
+ || (SYMBOL_REF_DECL (x)
+ && lookup_attribute ("noplt",
+ DECL_ATTRIBUTES (SYMBOL_REF_DECL (x)))))))
&& !SYMBOL_REF_LOCAL_P (x));
}
@@ -10596,7 +10601,8 @@ legitimate_pic_address_disp_p (rtx disp)
}
else if (!SYMBOL_REF_FAR_ADDR_P (op0)
&& (SYMBOL_REF_LOCAL_P (op0)
- || (HAVE_LD_PIE_COPYRELOC
+ || (flag_direct_extern_access
+ && HAVE_LD_PIE_COPYRELOC
&& flag_pie
&& !SYMBOL_REF_WEAK (op0)
&& !SYMBOL_REF_FUNCTION_P (op0)))
@@ -13498,7 +13504,7 @@ ix86_print_operand (FILE *file, rtx x, int code)
if (code == 'P')
{
- if (ix86_force_load_from_GOT_p (x))
+ if (ix86_force_load_from_GOT_p (x, true))
{
/* For inline assembly statement, load function address
from GOT with 'P' operand modifier to avoid PLT. */
@@ -21901,10 +21907,10 @@ ix86_stack_protect_fail (void)
int
asm_preferred_eh_data_format (int code, int global)
{
- if (flag_pic)
+ if (flag_pic || !flag_direct_extern_access)
{
int type = DW_EH_PE_sdata8;
- if (!TARGET_64BIT
+ if (ptr_mode == SImode
|| ix86_cmodel == CM_SMALL_PIC
|| (ix86_cmodel == CM_MEDIUM_PIC && (global || code)))
type = DW_EH_PE_sdata4;
@@ -22992,10 +22998,21 @@ ix86_atomic_assign_expand_fenv (tree *hold, tree *clear, tree *update)
static bool
ix86_binds_local_p (const_tree exp)
{
- return default_binds_local_p_3 (exp, flag_shlib != 0, true, true,
- (!flag_pic
- || (TARGET_64BIT
- && HAVE_LD_PIE_COPYRELOC != 0)));
+ return default_binds_local_p_3 (exp, flag_shlib != 0, true,
+ flag_direct_extern_access,
+ (flag_direct_extern_access
+ && (!flag_pic
+ || (TARGET_64BIT
+ && HAVE_LD_PIE_COPYRELOC != 0))));
+}
+
+/* If flag_pic or flag_direct_extern_access is false, then neither
+ local nor global relocs should be placed in readonly memory. */
+
+static int
+ix86_reloc_rw_mask (void)
+{
+ return (flag_pic || !flag_direct_extern_access) ? 3 : 0;
}
#endif
@@ -24022,6 +24039,11 @@ ix86_run_selftests (void)
#define TARGET_GET_MULTILIB_ABI_NAME \
ix86_get_multilib_abi_name
+#if !TARGET_MACHO && !TARGET_DLLIMPORT_DECL_ATTRIBUTES
+# undef TARGET_ASM_RELOC_RW_MASK
+# define TARGET_ASM_RELOC_RW_MASK ix86_reloc_rw_mask
+#endif
+
static bool ix86_libc_has_fast_function (int fcode ATTRIBUTE_UNUSED)
{
#ifdef OPTION_GLIBC
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index af2ce189fae..fd11a5b2ccc 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -657,6 +657,7 @@ Objective-C and Objective-C++ Dialects}.
-fnon-call-exceptions -fdelete-dead-exceptions -funwind-tables @gol
-fasynchronous-unwind-tables @gol
-fno-gnu-unique @gol
+-fno-direct-extern-access @gol
-finhibit-size-directive -fcommon -fno-ident @gol
-fpcc-struct-return -fpic -fPIC -fpie -fPIE -fno-plt @gol
-fno-jump-tables -fno-bit-tests @gol
@@ -16543,6 +16544,18 @@ through the PLT for specific external functions.
In position-dependent code, a few targets also convert calls to
functions that are marked to not use the PLT to use the GOT instead.
+@item -fno-direct-extern-access
+@opindex fno-direct-extern-access
+@opindex fdirect-extern-access
+Without @option{-fpic} nor @option{-fPIC}, always use the GOT pointer
+to access external symbols. With @option{-fpic} or @option{-fPIC},
+treat access to protected symbols as local symbols.
+
+@strong{Warning:} shared libraries compiled with
+@option{-fno-direct-extern-access} and executable compiled with
+@option{-fdirect-extern-access} may not be binary compatible if
+protected symbols are used in shared libraries and executable.
+
@item -fno-jump-tables
@opindex fno-jump-tables
@opindex fjump-tables
diff --git a/gcc/testsuite/g++.dg/pr35513-1.C b/gcc/testsuite/g++.dg/pr35513-1.C
new file mode 100644
index 00000000000..8423e826da8
--- /dev/null
+++ b/gcc/testsuite/g++.dg/pr35513-1.C
@@ -0,0 +1,25 @@
+// { dg-do run }
+// { dg-options "-O2 -fno-direct-extern-access" }
+
+#include <iostream>
+
+class Bug
+{
+};
+
+int throw_bug()
+{
+ throw Bug();
+
+ return 0;
+}
+
+int main()
+{
+ try {
+ std::cout << throw_bug();
+ } catch (Bug bug) {
+ };
+
+ return 0;
+}
diff --git a/gcc/testsuite/g++.dg/pr35513-2.C b/gcc/testsuite/g++.dg/pr35513-2.C
new file mode 100644
index 00000000000..56ed19ae1eb
--- /dev/null
+++ b/gcc/testsuite/g++.dg/pr35513-2.C
@@ -0,0 +1,53 @@
+// { dg-do run }
+// { dg-options "-O2 -fno-direct-extern-access" }
+
+class Foo
+{
+public:
+ Foo(int n) : n_(n) { }
+ int f() { return n_; }
+
+ int badTest();
+ int goodTest();
+
+private:
+
+ int n_;
+};
+
+int Foo::badTest()
+{
+ try {
+ throw int(99);
+ }
+
+ catch (int &i) {
+ n_ = 16;
+ }
+
+ return n_;
+}
+
+
+int Foo::goodTest()
+{
+ int n;
+
+ try {
+ throw int(99);
+ }
+
+ catch (int &i) {
+ n = 16;
+ }
+
+ return n_;
+}
+
+int main()
+{
+ Foo foo(5);
+ foo.goodTest();
+ foo.badTest();
+ return 0;
+}
diff --git a/gcc/testsuite/gcc.target/i386/pr35513-1.c b/gcc/testsuite/gcc.target/i386/pr35513-1.c
new file mode 100644
index 00000000000..c5dbabc3704
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr35513-1.c
@@ -0,0 +1,16 @@
+/* { dg-do compile { target *-*-linux* } } */
+/* { dg-options "-O2 -fno-pic -fno-direct-extern-access" } */
+
+extern void bar (void);
+extern void *p;
+
+void
+foo (void)
+{
+ p = &bar;
+}
+
+/* { dg-final { scan-assembler "mov\(l|q\)\[ \t\]*bar@GOTPCREL" { target { ! ia32 } } } } */
+/* { dg-final { scan-assembler "movl\[ \t\]*bar@GOT," { target { ia32 && got32x_reloc } } } } */
+/* { dg-final { scan-assembler-not "mov\(l|q\)\[ \t\]*\\\$bar," { target { ! ia32 } } } } */
+/* { dg-final { scan-assembler-not "mov\(l|q\)\[ \t\]*\\\$bar," { target { ia32 && got32x_reloc } } } } */
diff --git a/gcc/testsuite/gcc.target/i386/pr35513-2.c b/gcc/testsuite/gcc.target/i386/pr35513-2.c
new file mode 100644
index 00000000000..8bb7cb4c13d
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr35513-2.c
@@ -0,0 +1,15 @@
+/* { dg-do compile { target *-*-linux* } } */
+/* { dg-options "-O2 -fno-pic -fno-direct-extern-access" } */
+
+extern int bar;
+
+int
+foo (void)
+{
+ return bar;
+}
+
+/* { dg-final { scan-assembler "mov\(l|q\)\[ \t\]*bar@GOTPCREL" { target { ! ia32 } } } } */
+/* { dg-final { scan-assembler "movl\[ \t\]*bar@GOT," { target { ia32 && got32x_reloc } } } } */
+/* { dg-final { scan-assembler-not "mov\(l|q\)\[ \t\]*\\\$bar," { target { ! ia32 } } } } */
+/* { dg-final { scan-assembler-not "mov\(l|q\)\[ \t\]*\\\$bar," { target { ia32 && got32x_reloc } } } } */
diff --git a/gcc/testsuite/gcc.target/i386/pr35513-3.c b/gcc/testsuite/gcc.target/i386/pr35513-3.c
new file mode 100644
index 00000000000..98dc54e3bf4
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr35513-3.c
@@ -0,0 +1,15 @@
+/* { dg-do compile { target *-*-linux* } } */
+/* { dg-options "-O2 -fpie -fno-direct-extern-access" } */
+
+extern int bar;
+
+int
+foo (void)
+{
+ return bar;
+}
+
+/* { dg-final { scan-assembler "mov\(l|q\)\[ \t\]*bar@GOTPCREL" { target { ! ia32 } } } } */
+/* { dg-final { scan-assembler "movl\[ \t\]*bar@GOT" { target { ia32 && got32x_reloc } } } } */
+/* { dg-final { scan-assembler-not "mov\(l|q\)\[ \t\]*\\\$bar," { target { ! ia32 } } } } */
+/* { dg-final { scan-assembler-not "mov\(l|q\)\[ \t\]*\\\$bar," { target { ia32 && got32x_reloc } } } } */
diff --git a/gcc/testsuite/gcc.target/i386/pr35513-4.c b/gcc/testsuite/gcc.target/i386/pr35513-4.c
new file mode 100644
index 00000000000..467081dad65
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr35513-4.c
@@ -0,0 +1,15 @@
+/* { dg-do compile { target *-*-linux* } } */
+/* { dg-options "-O2 -fplt -fno-pic -fno-direct-extern-access" } */
+
+extern void foo (void);
+
+int
+bar (void)
+{
+ foo ();
+ return 0;
+}
+
+/* { dg-final { scan-assembler "call\[ \t\]*foo" } } */
+/* { dg-final { scan-assembler-not "foo@GOTPCREL" { target { ! ia32 } } } } */
+/* { dg-final { scan-assembler-not "foo@GOT" { target ia32 } } } */
diff --git a/gcc/testsuite/gcc.target/i386/pr35513-5.c b/gcc/testsuite/gcc.target/i386/pr35513-5.c
new file mode 100644
index 00000000000..b0e61b08ba9
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr35513-5.c
@@ -0,0 +1,15 @@
+/* { dg-do compile { target *-*-linux* } } */
+/* { dg-options "-O2 -fplt -fpic -fno-direct-extern-access" } */
+
+extern void foo (void);
+
+int
+bar (void)
+{
+ foo ();
+ return 0;
+}
+
+/* { dg-final { scan-assembler "call\[ \t\]*foo@PLT" } } */
+/* { dg-final { scan-assembler-not "foo@GOTPCREL" { target { ! ia32 } } } } */
+/* { dg-final { scan-assembler-not "foo@GOT" { target ia32 } } } */
diff --git a/gcc/testsuite/gcc.target/i386/pr35513-6.c b/gcc/testsuite/gcc.target/i386/pr35513-6.c
new file mode 100644
index 00000000000..270504b8d0e
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr35513-6.c
@@ -0,0 +1,14 @@
+/* { dg-do compile { target *-*-linux* } } */
+/* { dg-options "-O2 -fplt -fno-pic -fno-direct-extern-access" } */
+
+extern void foo (void);
+
+void
+bar (void)
+{
+ foo ();
+}
+
+/* { dg-final { scan-assembler "jmp\[ \t\]*foo" } } */
+/* { dg-final { scan-assembler-not "foo@GOTPCREL" { target { ! ia32 } } } } */
+/* { dg-final { scan-assembler-not "foo@GOT" { target ia32 } } } */
diff --git a/gcc/testsuite/gcc.target/i386/pr35513-7.c b/gcc/testsuite/gcc.target/i386/pr35513-7.c
new file mode 100644
index 00000000000..2c5a83ddef8
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr35513-7.c
@@ -0,0 +1,15 @@
+/* { dg-do compile { target *-*-linux* } } */
+/* { dg-options "-O2 -fplt -fpic -fno-direct-extern-access" } */
+
+extern void foo (void);
+
+void
+bar (void)
+{
+ foo ();
+}
+
+/* { dg-final { scan-assembler "jmp\[ \t\]*foo@PLT" { target { ! ia32 } } } } */
+/* { dg-final { scan-assembler "call\[ \t\]*foo@PLT" { target ia32 } } } */
+/* { dg-final { scan-assembler-not "foo@GOTPCREL" { target { ! ia32 } } } } */
+/* { dg-final { scan-assembler-not "foo@GOT" { target ia32 } } } */
diff --git a/gcc/testsuite/gcc.target/i386/pr35513-8.c b/gcc/testsuite/gcc.target/i386/pr35513-8.c
new file mode 100644
index 00000000000..545979e99c2
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr35513-8.c
@@ -0,0 +1,41 @@
+/* { dg-do assemble { target { *-*-linux* && { ! ia32 } } } } */
+/* { dg-require-effective-target maybe_x32 } */
+/* { dg-options "-mx32 -O2 -fno-pic -fexceptions -fasynchronous-unwind-tables -fno-direct-extern-access" } */
+
+extern int foo (int);
+extern void exit (int __status) __attribute__ ((__nothrow__ )) __attribute__ ((__noreturn__));
+struct __pthread_cleanup_frame
+{
+ void (*__cancel_routine) (void *);
+ void *__cancel_arg;
+ int __do_it;
+ int __cancel_type;
+};
+extern __inline void
+__pthread_cleanup_routine (struct __pthread_cleanup_frame *__frame)
+{
+ if (__frame->__do_it)
+ __frame->__cancel_routine (__frame->__cancel_arg);
+}
+static int cl_called;
+
+static void
+cl (void *arg)
+{
+ ++cl_called;
+}
+
+
+void *
+tf_usleep (void *arg)
+{
+
+ do { struct __pthread_cleanup_frame __clframe __attribute__ ((__cleanup__ (__pthread_cleanup_routine))) = { .__cancel_routine = (cl), .__cancel_arg = (
+ ((void *)0)), .__do_it = 1 };;
+
+ foo (arg == ((void *)0) ? (0x7fffffffL * 2UL + 1UL) : 0);
+
+ __clframe.__do_it = (0); } while (0);
+
+ exit (1);
+}
--
2.31.1
^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH v2 2/2] Add TARGET_ASM_EMIT_GNU_PROPERTY_NOTE
2021-06-24 13:47 [PATCH v2 0/2] Implement indirect external access H.J. Lu
2021-06-24 13:47 ` [PATCH v2 1/2] Add -f[no-]direct-extern-access H.J. Lu
@ 2021-06-24 13:47 ` H.J. Lu
1 sibling, 0 replies; 3+ messages in thread
From: H.J. Lu @ 2021-06-24 13:47 UTC (permalink / raw)
To: gcc-patches; +Cc: Uros Bizjak, Jakub Jelinek, Richard Biener
Generate the marker for -fno-direct-extern-access to indicate that the
object file uses GOT to access all external symbols. Access to protected
symbols in the resulting shared library is treated as local, which requires
canonical function pointers and cannot be used with copy relocation.
* configure.ac (HAVE_LD_INDIRECT_EXTERN_ACCESS_SUPPORT): New.
Define to 1 if linker supports -z indirect-extern-access.
* output.h (emit_gnu_property): New.
(emit_gnu_property_note): Likewise.
* target.def (emit_gnu_property_note): Add a argetm.asm_out hook.
* toplev.c (compile_file): Call emit_gnu_property_note before
file_end.
* varasm.c (emit_gnu_property): New.
(emit_gnu_property_note): Likewise.
* config.in: Regenerated.
* configure: Likewise.
* doc/tm.texi: Likewise.
* config/i386/gnu-property.c (emit_gnu_property): Removed.
(TARGET_ASM_EMIT_GNU_PROPERTY_NOTE): New.
* doc/tm.texi.in: Add TARGET_ASM_EMIT_GNU_PROPERTY_NOTE.
---
gcc/config.in | 6 +++++
gcc/config/i386/gnu-property.c | 31 ----------------------
gcc/config/i386/i386.c | 2 ++
gcc/configure | 24 +++++++++++++++++
gcc/configure.ac | 20 +++++++++++++++
gcc/doc/tm.texi | 5 ++++
gcc/doc/tm.texi.in | 2 ++
gcc/output.h | 2 ++
gcc/target.def | 8 ++++++
gcc/toplev.c | 3 +++
gcc/varasm.c | 47 ++++++++++++++++++++++++++++++++++
11 files changed, 119 insertions(+), 31 deletions(-)
diff --git a/gcc/config.in b/gcc/config.in
index 18e627141cc..7a3e003f8ac 100644
--- a/gcc/config.in
+++ b/gcc/config.in
@@ -1640,6 +1640,12 @@
#endif
+/* Define to 1 if your linker supports -z indirect-extern-access */
+#ifndef USED_FOR_TARGET
+#undef HAVE_LD_INDIRECT_EXTERN_ACCESS_SUPPORT
+#endif
+
+
/* Define if your PowerPC64 linker supports a large TOC. */
#ifndef USED_FOR_TARGET
#undef HAVE_LD_LARGE_TOC
diff --git a/gcc/config/i386/gnu-property.c b/gcc/config/i386/gnu-property.c
index 4ba04403002..9fe8d00132e 100644
--- a/gcc/config/i386/gnu-property.c
+++ b/gcc/config/i386/gnu-property.c
@@ -24,37 +24,6 @@ along with GCC; see the file COPYING3. If not see
#include "output.h"
#include "linux-common.h"
-static void
-emit_gnu_property (unsigned int type, unsigned int data)
-{
- int p2align = ptr_mode == SImode ? 2 : 3;
-
- switch_to_section (get_section (".note.gnu.property",
- SECTION_NOTYPE, NULL));
-
- ASM_OUTPUT_ALIGN (asm_out_file, p2align);
- /* name length. */
- fprintf (asm_out_file, ASM_LONG "1f - 0f\n");
- /* data length. */
- fprintf (asm_out_file, ASM_LONG "4f - 1f\n");
- /* note type: NT_GNU_PROPERTY_TYPE_0. */
- fprintf (asm_out_file, ASM_LONG "5\n");
- fprintf (asm_out_file, "0:\n");
- /* vendor name: "GNU". */
- fprintf (asm_out_file, STRING_ASM_OP "\"GNU\"\n");
- fprintf (asm_out_file, "1:\n");
- ASM_OUTPUT_ALIGN (asm_out_file, p2align);
- /* pr_type. */
- fprintf (asm_out_file, ASM_LONG "0x%x\n", type);
- /* pr_datasz. */
- fprintf (asm_out_file, ASM_LONG "3f - 2f\n");
- fprintf (asm_out_file, "2:\n");
- fprintf (asm_out_file, ASM_LONG "0x%x\n", data);
- fprintf (asm_out_file, "3:\n");
- ASM_OUTPUT_ALIGN (asm_out_file, p2align);
- fprintf (asm_out_file, "4:\n");
-}
-
void
file_end_indicate_exec_stack_and_gnu_property (void)
{
diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index 4ab85cc4fe0..8e86781299e 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -24042,6 +24042,8 @@ ix86_run_selftests (void)
#if !TARGET_MACHO && !TARGET_DLLIMPORT_DECL_ATTRIBUTES
# undef TARGET_ASM_RELOC_RW_MASK
# define TARGET_ASM_RELOC_RW_MASK ix86_reloc_rw_mask
+# undef TARGET_ASM_EMIT_GNU_PROPERTY_NOTE
+# define TARGET_ASM_EMIT_GNU_PROPERTY_NOTE emit_gnu_property_note
#endif
static bool ix86_libc_has_fast_function (int fcode ATTRIBUTE_UNUSED)
diff --git a/gcc/configure b/gcc/configure
index f0b2ebde3cf..1b92dd803ca 100755
--- a/gcc/configure
+++ b/gcc/configure
@@ -32177,6 +32177,30 @@ fi
{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ld_bndplt_support" >&5
$as_echo "$ld_bndplt_support" >&6; }
+# Check linker supports '-z indirect-extern-access'
+ld_indirect_extern_access=0
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking linker -z indirect-extern-access option" >&5
+$as_echo_n "checking linker -z indirect-extern-access option... " >&6; }
+if test x"$ld_is_gold" = xno; then
+ if test $in_tree_ld = yes ; then
+ if test "$gcc_cv_gld_major_version" -eq 2 -a "$gcc_cv_gld_minor_version" -ge 37 -o "$gcc_cv_gld_major_version" -gt 2; then
+ ld_indirect_extern_access=1
+ fi
+ elif test x$gcc_cv_ld != x; then
+ # Check if linker supports -z indirect-extern-access option
+ if $gcc_cv_ld --help 2>&1 | grep -- '-z indirect-extern-access' > /dev/null; then
+ ld_indirect_extern_access=1
+ fi
+ fi
+fi
+
+cat >>confdefs.h <<_ACEOF
+#define HAVE_LD_INDIRECT_EXTERN_ACCESS_SUPPORT $ld_indirect_extern_access
+_ACEOF
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ld_indirect_extern_access" >&5
+$as_echo "$ld_indirect_extern_access" >&6; }
+
# Check linker supports '--push-state'/'--pop-state'
ld_pushpopstate_support=no
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking linker --push-state/--pop-state options" >&5
diff --git a/gcc/configure.ac b/gcc/configure.ac
index 70089394429..aa905efe4e9 100644
--- a/gcc/configure.ac
+++ b/gcc/configure.ac
@@ -7483,6 +7483,26 @@ if test x"$ld_bndplt_support" = xyes; then
fi
AC_MSG_RESULT($ld_bndplt_support)
+# Check linker supports '-z indirect-extern-access'
+ld_indirect_extern_access=0
+AC_MSG_CHECKING(linker -z indirect-extern-access option)
+if test x"$ld_is_gold" = xno; then
+ if test $in_tree_ld = yes ; then
+ if test "$gcc_cv_gld_major_version" -eq 2 -a "$gcc_cv_gld_minor_version" -ge 37 -o "$gcc_cv_gld_major_version" -gt 2; then
+ ld_indirect_extern_access=1
+ fi
+ elif test x$gcc_cv_ld != x; then
+ # Check if linker supports -z indirect-extern-access option
+ if $gcc_cv_ld --help 2>&1 | grep -- '-z indirect-extern-access' > /dev/null; then
+ ld_indirect_extern_access=1
+ fi
+ fi
+fi
+AC_DEFINE_UNQUOTED(HAVE_LD_INDIRECT_EXTERN_ACCESS_SUPPORT,
+ $ld_indirect_extern_access,
+ [Define to 1 if your linker supports -z indirect-extern-access])
+AC_MSG_RESULT($ld_indirect_extern_access)
+
# Check linker supports '--push-state'/'--pop-state'
ld_pushpopstate_support=no
AC_MSG_CHECKING(linker --push-state/--pop-state options)
diff --git a/gcc/doc/tm.texi b/gcc/doc/tm.texi
index 2a41ae5fba1..5b1f5c135b0 100644
--- a/gcc/doc/tm.texi
+++ b/gcc/doc/tm.texi
@@ -8073,6 +8073,11 @@ Output to @code{asm_out_file} any text which the assembler expects
to find at the end of a file. The default is to output nothing.
@end deftypefn
+@deftypefn {Target Hook} void TARGET_ASM_EMIT_GNU_PROPERTY_NOTE (void)
+Output a GNU property note to @code{asm_out_file}. The default is to
+output nothing.
+@end deftypefn
+
@deftypefun void file_end_indicate_exec_stack ()
Some systems use a common convention, the @samp{.note.GNU-stack}
special section, to indicate whether or not an object file relies on
diff --git a/gcc/doc/tm.texi.in b/gcc/doc/tm.texi.in
index f881cdabe9e..7091e02ca81 100644
--- a/gcc/doc/tm.texi.in
+++ b/gcc/doc/tm.texi.in
@@ -5050,6 +5050,8 @@ This describes the overall framework of an assembly file.
@hook TARGET_ASM_FILE_END
+@hook TARGET_ASM_EMIT_GNU_PROPERTY_NOTE
+
@deftypefun void file_end_indicate_exec_stack ()
Some systems use a common convention, the @samp{.note.GNU-stack}
special section, to indicate whether or not an object file relies on
diff --git a/gcc/output.h b/gcc/output.h
index 73ca4545f4f..f9cbf7cab37 100644
--- a/gcc/output.h
+++ b/gcc/output.h
@@ -607,6 +607,8 @@ extern void default_asm_declare_constant_name (FILE *, const char *,
extern void default_file_start (void);
extern void file_end_indicate_exec_stack (void);
extern void file_end_indicate_split_stack (void);
+extern void emit_gnu_property (unsigned int, unsigned int);
+extern void emit_gnu_property_note (void);
extern void default_elf_asm_output_external (FILE *file, tree,
const char *);
diff --git a/gcc/target.def b/gcc/target.def
index c009671c583..31e8bc0ab97 100644
--- a/gcc/target.def
+++ b/gcc/target.def
@@ -715,6 +715,14 @@ to find at the end of a file. The default is to output nothing.",
void, (void),
hook_void_void)
+/* Output a GNU property note. */
+DEFHOOK
+(emit_gnu_property_note,
+ "Output a GNU property note to @code{asm_out_file}. The default is to\n\
+output nothing.",
+ void, (void),
+ hook_void_void)
+
/* Output any boilerplate text needed at the beginning of an
LTO output stream. */
DEFHOOK
diff --git a/gcc/toplev.c b/gcc/toplev.c
index 55e7550151f..bddcfdf5bde 100644
--- a/gcc/toplev.c
+++ b/gcc/toplev.c
@@ -585,6 +585,9 @@ compile_file (void)
/* Invoke registered plugin callbacks. */
invoke_plugin_callbacks (PLUGIN_FINISH_UNIT, NULL);
+ /* Output a GNU property note. */
+ targetm.asm_out.emit_gnu_property_note ();
+
/* This must be at the end. Some target ports emit end of file directives
into the assembly file here, and hence we cannot output anything to the
assembly file after this point. */
diff --git a/gcc/varasm.c b/gcc/varasm.c
index 53cf6dea3f3..b0850864534 100644
--- a/gcc/varasm.c
+++ b/gcc/varasm.c
@@ -7729,6 +7729,53 @@ default_file_start (void)
}
}
+/* Emit one GNU property of TYPE and DATA. */
+
+void
+emit_gnu_property (unsigned int type, unsigned int data)
+{
+ int p2align = ptr_mode == SImode ? 2 : 3;
+
+ switch_to_section (get_section (".note.gnu.property",
+ SECTION_NOTYPE, NULL));
+
+ ASM_OUTPUT_ALIGN (asm_out_file, p2align);
+ /* name length. */
+ fprintf (asm_out_file, ASM_LONG "1f - 0f\n");
+ /* data length. */
+ fprintf (asm_out_file, ASM_LONG "4f - 1f\n");
+ /* note type: NT_GNU_PROPERTY_TYPE_0. */
+ fprintf (asm_out_file, ASM_LONG "5\n");
+ fprintf (asm_out_file, "0:\n");
+ /* vendor name: "GNU". */
+ fprintf (asm_out_file, STRING_ASM_OP "\"GNU\"\n");
+ fprintf (asm_out_file, "1:\n");
+ ASM_OUTPUT_ALIGN (asm_out_file, p2align);
+ /* pr_type. */
+ fprintf (asm_out_file, ASM_LONG "0x%x\n", type);
+ /* pr_datasz. */
+ fprintf (asm_out_file, ASM_LONG "3f - 2f\n");
+ fprintf (asm_out_file, "2:\n");
+ fprintf (asm_out_file, ASM_LONG "0x%x\n", data);
+ fprintf (asm_out_file, "3:\n");
+ ASM_OUTPUT_ALIGN (asm_out_file, p2align);
+ fprintf (asm_out_file, "4:\n");
+}
+
+/* This is a generic routine for TARGET_ASM_EMIT_GNU_PROPERTY_NOTE to
+ emit a NT_GNU_PROPERTY_TYPE_0 note. This is primarily a GNU extension
+ to ELF but could be used on other targets. */
+
+void
+emit_gnu_property_note (void)
+{
+ if (HAVE_LD_INDIRECT_EXTERN_ACCESS_SUPPORT
+ && !flag_direct_extern_access)
+ /* Emite a GNU_PROPERTY_1_NEEDED note with
+ GNU_PROPERTY_1_NEEDED_INDIRECT_EXTERN_ACCESS. */
+ emit_gnu_property (0xb0008000, (1U << 0));
+}
+
/* This is a generic routine suitable for use as TARGET_ASM_FILE_END
which emits a special section directive used to indicate whether or
not this object file needs an executable stack. This is primarily
--
2.31.1
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2021-06-24 13:48 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-06-24 13:47 [PATCH v2 0/2] Implement indirect external access H.J. Lu
2021-06-24 13:47 ` [PATCH v2 1/2] Add -f[no-]direct-extern-access H.J. Lu
2021-06-24 13:47 ` [PATCH v2 2/2] Add TARGET_ASM_EMIT_GNU_PROPERTY_NOTE H.J. Lu
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).