RISC-V: PR28509, the default visibility symbol cannot be referenced by R_RISCV_JAL.

When generating the shared object, the default visibility symbols may bind
externally, which means they will be exported to the dynamic symbol table,
and are preemptible by default.  These symbols cannot be referenced by the
non-pic R_RISCV_JAL and R_RISCV_RVC_JUMP.  However, consider that linker
may relax the R_RISCV_CALL relocations to R_RISCV_JAL or R_RISCV_RVC_JUMP,
if these relocations are relocated to the plt entries, then we won't report
error for them.  Perhaps we also need the similar checks for the
R_RISCV_BRANCH and R_RISCV_RVC_BRANCH relocations.

After applying this patch, and revert the following glibc patch,
riscv: Fix incorrect jal with HIDDEN_JUMPTARGET
https://sourceware.org/git/?p=glibc.git;a=commit;h=68389203832ab39dd0dbaabbc4059e7fff51c29b

I get the expected errors as follows,
ld: relocation R_RISCV_RVC_JUMP against `__sigsetjmp' which may bind externally can not be used when making a shared object; recompile with -fPIC
ld: relocation R_RISCV_JAL against `exit' which may bind externally can not be used when making a shared object; recompile with -fPIC

Besides, we also have similar changes for libgcc,
RISC-V: jal cannot refer to a default visibility symbol for shared object
45116f3420

bfd/
	pr 28509
	* elfnn-riscv.c (riscv_elf_relocate_section): Report errors when
	makeing a shard object, and the referenced symbols of R_RISCV_JAL
	relocations are default visibility.  Besides, we should handle most
	of the cases here, so don't need the unresolvable check later for
	R_RISCV_JAL and R_RISCV_RVC_JUMP.
ld/
	pr 28509
	* testsuite/ld-riscv-elf/ld-riscv-elf.exp: Updated.
	* testsuite/ld-riscv-elf/lib-nopic-01a.s: Removed.
	* testsuite/ld-riscv-elf/lib-nopic-01b.d: Likewise.
	* testsuite/ld-riscv-elf/lib-nopic-01b.s: Likewise.
	* testsuite/ld-riscv-elf/shared-lib-nopic-01.d: New testcase.
	* testsuite/ld-riscv-elf/shared-lib-nopic-01.s: Likewise.
	* testsuite/ld-riscv-elf/shared-lib-nopic-02.d: Likewise.
	* testsuite/ld-riscv-elf/shared-lib-nopic-02.s: Likewise.
	* testsuite/ld-riscv-elf/shared-lib-nopic-03.d: Likewise.
	* testsuite/ld-riscv-elf/shared-lib-nopic-03.s: Likewise.
	* testsuite/ld-riscv-elf/shared-lib-nopic-04.d: Likewise.
	* testsuite/ld-riscv-elf/shared-lib-nopic-04.s: Likewise.

bfd/elfnn-riscv.c

@@ -2457,12 +2457,44 @@ riscv_elf_relocate_section (bfd *output_bfd,
 
 	case R_RISCV_JAL:
 	case R_RISCV_RVC_JUMP:
-	  /* This line has to match the check in _bfd_riscv_relax_section.  */
-	  if (bfd_link_pic (info) && h != NULL && h->plt.offset != MINUS_ONE)
+	  if (bfd_link_pic (info) && h != NULL)
 	    {
-	      /* Refer to the PLT entry.  */
-	      relocation = sec_addr (htab->elf.splt) + h->plt.offset;
-	      unresolved_reloc = false;
+	      if (h->plt.offset != MINUS_ONE)
+		{
+		  /* Refer to the PLT entry.  This check has to match the
+		     check in _bfd_riscv_relax_section.  */
+		  relocation = sec_addr (htab->elf.splt) + h->plt.offset;
+		  unresolved_reloc = false;
+		}
+	      else if (!SYMBOL_REFERENCES_LOCAL (info, h)
+		       && (input_section->flags & SEC_ALLOC) != 0
+		       && (input_section->flags & SEC_READONLY) != 0
+		       && ELF_ST_VISIBILITY (h->other) == STV_DEFAULT)
+		{
+		  /* PR 28509, when generating the shared object, these
+		     referenced symbols may bind externally, which means
+		     they will be exported to the dynamic symbol table,
+		     and are preemptible by default.  These symbols cannot
+		     be referenced by the non-pic relocations, like
+		     R_RISCV_JAL and R_RISCV_RVC_JUMP relocations.
+
+		     However, consider that linker may relax the R_RISCV_CALL
+		     relocations to R_RISCV_JAL or R_RISCV_RVC_JUMP, if
+		     these relocations are relocated to the plt entries,
+		     then we won't report error for them.
+
+		     Perhaps we also need the similar checks for the
+		     R_RISCV_BRANCH and R_RISCV_RVC_BRANCH relocations.  */
+		  if (asprintf (&msg_buf,
+				_("%%X%%P: relocation %s against `%s' which "
+				  "may bind externally can not be used when "
+				  "making a shared object; recompile "
+				  "with -fPIC\n"),
+				howto->name, h->root.root.string) == -1)
+		    msg_buf = NULL;
+		  msg = msg_buf;
+		  r = bfd_reloc_notsupported;
+		}
 	    }
 	  break;
 
@@ -2755,29 +2787,12 @@ riscv_elf_relocate_section (bfd *output_bfd,
 	  && _bfd_elf_section_offset (output_bfd, info, input_section,
 				      rel->r_offset) != (bfd_vma) -1)
 	{
-	  switch (r_type)
-	    {
-	    case R_RISCV_JAL:
-	    case R_RISCV_RVC_JUMP:
-	      if (asprintf (&msg_buf,
-			    _("%%X%%P: relocation %s against `%s' can "
-			      "not be used when making a shared object; "
-			      "recompile with -fPIC\n"),
-			    howto->name,
-			    h->root.root.string) == -1)
-		msg_buf = NULL;
-	      break;
-
-	    default:
-	      if (asprintf (&msg_buf,
-			    _("%%X%%P: unresolvable %s relocation against "
-			      "symbol `%s'\n"),
-			    howto->name,
-			    h->root.root.string) == -1)
-		msg_buf = NULL;
-	      break;
-	    }
-
+	  if (asprintf (&msg_buf,
+			_("%%X%%P: unresolvable %s relocation against "
+			  "symbol `%s'\n"),
+			howto->name,
+			h->root.root.string) == -1)
+	    msg_buf = NULL;
 	  msg = msg_buf;
 	  r = bfd_reloc_notsupported;
 	}

ld/testsuite/ld-riscv-elf/ld-riscv-elf.exp

@@ -210,12 +210,10 @@ if [istarget "riscv*-*-*"] {
 				    "gp-test-${abi}"]]
     }
 
-    run_ld_link_tests {
-	{ "Link non-pic code into a shared library (setup)"
-	    "-shared" "" "" {lib-nopic-01a.s}
-	    {} "lib-nopic-01a.so" }
-    }
-    run_dump_test "lib-nopic-01b"
+    run_dump_test "shared-lib-nopic-01"
+    run_dump_test "shared-lib-nopic-02"
+    run_dump_test "shared-lib-nopic-03"
+    run_dump_test "shared-lib-nopic-04"
 
     # IFUNC testcases.
     # Check IFUNC by single type relocs.

ld/testsuite/ld-riscv-elf/lib-nopic-01a.s

@@ -1,9 +0,0 @@
-        .option nopic
-	.text
-	.align  1
-	.globl  func1
-	.type   func1, @function
-func1:
-	jal	func2
-	jr      ra
-	.size   func1, .-func1

ld/testsuite/ld-riscv-elf/lib-nopic-01b.d

@@ -1,5 +0,0 @@
-#name: link non-pic code into a shared library
-#source: lib-nopic-01b.s
-#as:
-#ld: -shared tmpdir/lib-nopic-01a.so
-#error: .*relocation R_RISCV_JAL against `func1' can not be used when making a shared object; recompile with -fPIC

ld/testsuite/ld-riscv-elf/lib-nopic-01b.s

@@ -1,9 +0,0 @@
-        .option nopic
-	.text
-	.align  1
-	.globl  func2
-	.type   func2, @function
-func2:
-	jal	func1
-	jr      ra
-	.size   func2, .-func2

ld/testsuite/ld-riscv-elf/shared-lib-nopic-01.d

@@ -0,0 +1,4 @@
+#source: shared-lib-nopic-01.s
+#as:
+#ld: -shared
+#error: .*relocation R_RISCV_JAL against `foo' which may bind externally can not be used when making a shared object; recompile with -fPIC

ld/testsuite/ld-riscv-elf/shared-lib-nopic-01.s

@@ -0,0 +1,3 @@
+        .option nopic
+	.text
+	jal	foo	# undefined

ld/testsuite/ld-riscv-elf/shared-lib-nopic-02.d

@@ -0,0 +1,4 @@
+#source: shared-lib-nopic-02.s
+#as:
+#ld: -shared
+#error: .*relocation R_RISCV_JAL against `foo_default' which may bind externally can not be used when making a shared object; recompile with -fPIC

ld/testsuite/ld-riscv-elf/shared-lib-nopic-02.s

@@ -0,0 +1,12 @@
+        .option nopic
+	.text
+	.align  1
+
+	jal	foo_default
+
+	.globl  foo_default
+	.type   foo_default, @function
+foo_default:
+	nop
+	ret
+	.size   foo_default, .-foo_default

ld/testsuite/ld-riscv-elf/shared-lib-nopic-03.d

@@ -0,0 +1,14 @@
+#source: shared-lib-nopic-03.s
+#as:
+#ld: -shared
+#objdump: -d
+
+.*:[ 	]+file format .*
+
+Disassembly of section \.text:
+
+#...
+.*:[ 	]+[0-9a-f]+[ 	]+jal[ 	]+.* <foo_default>
+
+0+[0-9a-f]+ <foo_default>:
+#...

ld/testsuite/ld-riscv-elf/shared-lib-nopic-03.s

@@ -0,0 +1,13 @@
+        .option nopic
+	.text
+	.align  1
+
+	jal	foo_default
+
+	.globl  foo_default
+	.hidden	foo_default
+	.type   foo_default, @function
+foo_default:
+	nop
+	ret
+	.size   foo_default, .-foo_default

ld/testsuite/ld-riscv-elf/shared-lib-nopic-04.d

@@ -0,0 +1,15 @@
+#source: shared-lib-nopic-04.s
+#as:
+#ld: -shared
+#objdump: -d
+
+.*:[ 	]+file format .*
+
+#...
+Disassembly of section \.text:
+#...
+.*:[ 	]+[0-9a-f]+[ 	]+jal[ 	]+.* <foo_default@plt>
+.*:[ 	]+[0-9a-f]+[ 	]+jal[ 	]+.* <foo_default@plt>
+
+0+[0-9a-f]+ <foo_default>:
+#...

ld/testsuite/ld-riscv-elf/shared-lib-nopic-04.s

@@ -0,0 +1,14 @@
+        .option nopic
+	.text
+	.align  1
+
+	call	foo_default
+	jal	foo_default
+
+
+	.globl  foo_default
+	.type   foo_default, @function
+foo_default:
+	nop
+	ret
+	.size   foo_default, .-foo_default