From: Alan Modra <amodra@gmail.com>
Date: Fri, 30 Oct 2020 04:26:35 +0000 (+1030)
Subject: PR26806, Suspected linker bug with LTO
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=b1a92c635c1ec10fd703302ce1fc4ab3a8515a04;p=binutils-gdb.git

PR26806, Suspected linker bug with LTO

This patch reverts most of git commit 1e3b96fd6cf, so IR symbols are
again not marked def_regular or ref_regular.  That should be enough to
stop IR symbols from becoming dynamic.  To mark as-needed shared
libraries referenced by IR symbols, use the referencing BFD rather
than the ref flags.

bfd/
	PR 15146
	PR 26314
	PR 26530
	PR 26806
	* elflink.c (elf_link_add_object_symbols): Don't set def/ref flags
	for plugin syms.  Do allow plugin syms to mark as-needed libs.
ld/
	PR 26806
	* testsuite/ld-plugin/lto-19.h,
	* testsuite/ld-plugin/lto-19a.c,
	* testsuite/ld-plugin/lto-19b.c,
	* testsuite/ld-plugin/lto-19c.c: New test.
	* testsuite/ld-plugin/pr26806.c,
	* testsuite/ld-plugin/pr26806.d: New test.
	* testsuite/ld-plugin/lto.exp: Run them.
---

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index a12ba7de337..e632282a71c 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,12 @@
+2020-11-02  Alan Modra  <amodra@gmail.com>
+
+	PR 15146
+	PR 26314
+	PR 26530
+	PR 26806
+	* elflink.c (elf_link_add_object_symbols): Don't set def/ref flags
+	for plugin syms.  Do allow plugin syms to mark as-needed libs.
+
 2020-10-30  H.J. Lu  <hongjiu.lu@intel.com>
 
 	PR gas/26703
diff --git a/bfd/elflink.c b/bfd/elflink.c
index e23d189b983..4b035a2cd56 100644
--- a/bfd/elflink.c
+++ b/bfd/elflink.c
@@ -4989,7 +4989,10 @@ elf_link_add_object_symbols (bfd *abfd, struct bfd_link_info *info)
 	     object and a shared object.  */
 	  bfd_boolean dynsym = FALSE;
 
-	  if (! dynamic)
+	  /* Plugin symbols aren't normal.  Don't set def/ref flags.  */
+	  if ((abfd->flags & BFD_PLUGIN) != 0)
+	    ;
+	  else if (!dynamic)
 	    {
 	      if (! definition)
 		{
@@ -5006,14 +5009,6 @@ elf_link_add_object_symbols (bfd *abfd, struct bfd_link_info *info)
 		      h->ref_dynamic = 1;
 		    }
 		}
-
-	      /* If the indirect symbol has been forced local, don't
-		 make the real symbol dynamic.  */
-	      if ((h == hi || !hi->forced_local)
-		  && (bfd_link_dll (info)
-		      || h->def_dynamic
-		      || h->ref_dynamic))
-		dynsym = TRUE;
 	    }
 	  else
 	    {
@@ -5027,14 +5022,25 @@ elf_link_add_object_symbols (bfd *abfd, struct bfd_link_info *info)
 		  h->def_dynamic = 1;
 		  hi->def_dynamic = 1;
 		}
+	    }
 
-	      /* If the indirect symbol has been forced local, don't
-		 make the real symbol dynamic.  */
-	      if ((h == hi || !hi->forced_local)
-		  && (h->def_regular
-		      || h->ref_regular
-		      || (h->is_weakalias
-			  && weakdef (h)->dynindx != -1)))
+	  /* If an indirect symbol has been forced local, don't
+	     make the real symbol dynamic.  */
+	  if (h != hi && hi->forced_local)
+	    ;
+	  else if (!dynamic)
+	    {
+	      if (bfd_link_dll (info)
+		  || h->def_dynamic
+		  || h->ref_dynamic)
+		dynsym = TRUE;
+	    }
+	  else
+	    {
+	      if (h->def_regular
+		  || h->ref_regular
+		  || (h->is_weakalias
+		      && weakdef (h)->dynindx != -1))
 		dynsym = TRUE;
 	    }
 
@@ -5170,6 +5176,10 @@ elf_link_add_object_symbols (bfd *abfd, struct bfd_link_info *info)
 	      && !bfd_link_relocatable (info))
 	    dynsym = FALSE;
 
+	  /* Nor should we make plugin symbols dynamic.  */
+	  if ((abfd->flags & BFD_PLUGIN) != 0)
+	    dynsym = FALSE;
+
 	  if (definition)
 	    {
 	      h->target_internal = isym->st_target_internal;
@@ -5196,7 +5206,7 @@ elf_link_add_object_symbols (bfd *abfd, struct bfd_link_info *info)
 		}
 	    }
 
-	  if (dynsym && (abfd->flags & BFD_PLUGIN) == 0 && h->dynindx == -1)
+	  if (dynsym && h->dynindx == -1)
 	    {
 	      if (! bfd_elf_link_record_dynamic_symbol (info, h))
 		goto error_free_vers;
@@ -5225,6 +5235,9 @@ elf_link_add_object_symbols (bfd *abfd, struct bfd_link_info *info)
 	      && definition
 	      && ((dynsym
 		   && h->ref_regular_nonweak)
+		  || (old_bfd != NULL
+		      && (old_bfd->flags & BFD_PLUGIN) != 0
+		      && bind != STB_WEAK)
 		  || (h->ref_dynamic_nonweak
 		      && (elf_dyn_lib_class (abfd) & DYN_AS_NEEDED) != 0
 		      && !on_needed_list (elf_dt_name (abfd),
diff --git a/ld/ChangeLog b/ld/ChangeLog
index 3f39eb462e7..f980e623944 100644
--- a/ld/ChangeLog
+++ b/ld/ChangeLog
@@ -1,3 +1,14 @@
+2020-11-02  Alan Modra  <amodra@gmail.com>
+
+	PR 26806
+	* testsuite/ld-plugin/lto-19.h,
+	* testsuite/ld-plugin/lto-19a.c,
+	* testsuite/ld-plugin/lto-19b.c,
+	* testsuite/ld-plugin/lto-19c.c: New test.
+	* testsuite/ld-plugin/pr26806.c,
+	* testsuite/ld-plugin/pr26806.d: New test.
+	* testsuite/ld-plugin/lto.exp: Run them.
+
 2020-10-30  H.J. Lu  <hongjiu.lu@intel.com>
 
 	PR gas/26703
diff --git a/ld/testsuite/ld-plugin/lto-19.h b/ld/testsuite/ld-plugin/lto-19.h
new file mode 100644
index 00000000000..0ca48d1f1aa
--- /dev/null
+++ b/ld/testsuite/ld-plugin/lto-19.h
@@ -0,0 +1,6 @@
+struct re_dfa_t {
+  const int *sb_char;
+};
+struct re_dfa_t *xregcomp (void);
+struct re_dfa_t *rpl_regcomp (void);
+void rpl_regfree (struct re_dfa_t *);
diff --git a/ld/testsuite/ld-plugin/lto-19a.c b/ld/testsuite/ld-plugin/lto-19a.c
new file mode 100644
index 00000000000..6213f79144d
--- /dev/null
+++ b/ld/testsuite/ld-plugin/lto-19a.c
@@ -0,0 +1,19 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include "lto-19.h"
+
+static const int utf8_sb_map[4] = { 0x12, 0x34, 0x56, 0x78 };
+
+struct re_dfa_t *
+rpl_regcomp ()
+{
+  struct re_dfa_t *dfa = malloc (sizeof (struct re_dfa_t));
+  dfa->sb_char = utf8_sb_map;
+  return dfa;
+}
+
+void
+rpl_regfree (struct re_dfa_t *dfa)
+{
+  puts (dfa->sb_char == utf8_sb_map ? "PASS" : "FAIL");
+}
diff --git a/ld/testsuite/ld-plugin/lto-19b.c b/ld/testsuite/ld-plugin/lto-19b.c
new file mode 100644
index 00000000000..b784f84ce06
--- /dev/null
+++ b/ld/testsuite/ld-plugin/lto-19b.c
@@ -0,0 +1,7 @@
+#include "lto-19.h"
+
+struct re_dfa_t *
+xregcomp (void)
+{
+  return rpl_regcomp ();
+}
diff --git a/ld/testsuite/ld-plugin/lto-19c.c b/ld/testsuite/ld-plugin/lto-19c.c
new file mode 100644
index 00000000000..0d231ba5725
--- /dev/null
+++ b/ld/testsuite/ld-plugin/lto-19c.c
@@ -0,0 +1,9 @@
+#include "lto-19.h"
+
+int
+main ()
+{
+  struct re_dfa_t *dfa = xregcomp ();
+  rpl_regfree (dfa);
+  return 0;
+}
diff --git a/ld/testsuite/ld-plugin/lto.exp b/ld/testsuite/ld-plugin/lto.exp
index 9f9f2d13ced..23c948cc643 100644
--- a/ld/testsuite/ld-plugin/lto.exp
+++ b/ld/testsuite/ld-plugin/lto.exp
@@ -403,6 +403,18 @@ set lto_link_elf_tests [list \
   [list {lto-18d.o} \
    {} {-flto -O2} \
    {lto-18d.c} {} {}] \
+  [list {liblto-19.a} \
+   "$plug_opt" {-flto -O2 -fPIC} \
+   {lto-19a.c} {} {liblto-19.a}] \
+  [list {compile lto-19b.c} \
+   "$plug_opt" {-flto -O2 -fPIC} \
+   {lto-19b.c} {} {} {c}] \
+  [list {liblto-19.so} \
+   {-shared tmpdir/lto-19b.o tmpdir/liblto-19.a} {-O2 -fPIC} \
+   {dummy.c} {} {liblto-19.so}] \
+  [list {pr26806.so} \
+   {-shared} {-fpic -O2 -flto} \
+   {pr26806.c} {{nm {-D} pr26806.d}} {pr26806.so}] \
 ]
 
 # PR 14918 checks that libgcc is not spuriously included in a shared link of
@@ -584,6 +596,10 @@ set lto_run_elf_shared_tests [list \
    {-static -flto -fuse-linker-plugin} {} \
    {lto-18a.c} {lto-18-4.exe} {lto-18.out} {-flto -O2} {c} {} \
    { -Ltmpdir -llto-18b -llto-18c tmpdir/lto-18d.o}] \
+  [list {lto-19} \
+   {-Wl,--as-needed,-R,tmpdir} {} \
+   {lto-19c.c} {lto-19.exe} {pass.out} {-flto -O2} {c} {} \
+   {tmpdir/liblto-19.so tmpdir/liblto-19.a}] \
 ]
 
 # LTO run-time tests for ELF
diff --git a/ld/testsuite/ld-plugin/pr26806.c b/ld/testsuite/ld-plugin/pr26806.c
new file mode 100644
index 00000000000..8bb29316f58
--- /dev/null
+++ b/ld/testsuite/ld-plugin/pr26806.c
@@ -0,0 +1,2 @@
+#include <unistd.h>
+int foo (int x) { if (__builtin_constant_p (x)) return getpid (); return 0; }
diff --git a/ld/testsuite/ld-plugin/pr26806.d b/ld/testsuite/ld-plugin/pr26806.d
new file mode 100644
index 00000000000..16fa828e136
--- /dev/null
+++ b/ld/testsuite/ld-plugin/pr26806.d
@@ -0,0 +1,4 @@
+#failif
+#...
+.* _*getpid[@ ].*
+#...