[binutils-gdb/binutils-2_43-branch] LTO: Restore the wrapper symbol check for standard function

[binutils-gdb/binutils-2_43-branch] LTO: Restore the wrapper symbol check for standard function

[Alan Modra]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=2fbb863136724cfef2fc2f4c2b7f51be36f132c7

commit 2fbb863136724cfef2fc2f4c2b7f51be36f132c7
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Fri Aug 2 19:52:00 2024 -0700

    LTO: Restore the wrapper symbol check for standard function
    
    Call unwrap_hash_lookup to restore the wrapper symbol check for standard
    function since reference to standard function may not show up in LTO
    symbol table:
    
    [hjl@gnu-tgl-3 pr31956-3]$ nm foo.o
    00000000 T main
             U __real_malloc
    00000000 T __wrap_malloc
    [hjl@gnu-tgl-3 pr31956-3]$  lto-dump -list foo.o
    Type   Visibility  Size  Name
    function  default     0  malloc
    function  default     0  __real_malloc
    function  default     3  main
    function  default     5  __wrap_malloc
    [hjl@gnu-tgl-3 pr31956-3]$ make
    gcc -O2 -flto -Wall   -c -o foo.o foo.c
    gcc -Wl,--wrap=malloc -O2 -flto -Wall -o x foo.o
    /usr/local/bin/ld: /tmp/ccsPW0a9.ltrans0.ltrans.o: in function `main':
    <artificial>:(.text.startup+0xa): undefined reference to `__wrap_malloc'
    collect2: error: ld returned 1 exit status
    make: *** [Makefile:22: x] Error 1
    [hjl@gnu-tgl-3 pr31956-3]$
    
    Also add a test to verify that the unused wrapper is removed.
    
            PR ld/31956
            * plugin.c (get_symbols): Restore the wrapper symbol check for
            standard function.
            * testsuite/ld-plugin/lto.exp: Run the malloc test and the
            unused test.
            * testsuite/ld-plugin/pr31956c.c: New file.
            * testsuite/ld-plugin/pr31956d.c: New file.
            * testsuite/ld-plugin/pr31956d.d: New file.
    
    Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
    (cherry picked from commit 3221c470f0765886a49a1a3d2ec602e4104a377b)

Diff:
---
 ld/plugin.c                       | 14 ++++++++++++--
 ld/testsuite/ld-plugin/lto.exp    | 16 ++++++++++++++++
 ld/testsuite/ld-plugin/pr31956c.c | 19 +++++++++++++++++++
 ld/testsuite/ld-plugin/pr31956d.c |  7 +++++++
 ld/testsuite/ld-plugin/pr31956d.d |  4 ++++
 5 files changed, 58 insertions(+), 2 deletions(-)

diff --git a/ld/plugin.c b/ld/plugin.c
index 03ee9880d10..51c4765cc5b 100644
--- a/ld/plugin.c
+++ b/ld/plugin.c
@@ -778,8 +778,18 @@ get_symbols (const void *handle, int nsyms, struct ld_plugin_symbol *syms,
 	{
 	  blhe = h;
 	  /* Check if a symbol is a wrapper symbol.  */
-	  if (blhe && blhe->wrapper_symbol)
-	    wrap_status = wrapper;
+	  if (blhe)
+	    {
+	      if (blhe->wrapper_symbol)
+		wrap_status = wrapper;
+	      else if (link_info.wrap_hash != NULL)
+		{
+		  struct bfd_link_hash_entry *unwrap
+		    = unwrap_hash_lookup (&link_info, (bfd *) abfd, blhe);
+		  if (unwrap != NULL && unwrap != h)
+		    wrap_status = wrapper;
+		}
+	    }
 	}
       else
 	{
diff --git a/ld/testsuite/ld-plugin/lto.exp b/ld/testsuite/ld-plugin/lto.exp
index 9476caf7ab4..604dc8c284d 100644
--- a/ld/testsuite/ld-plugin/lto.exp
+++ b/ld/testsuite/ld-plugin/lto.exp
@@ -546,6 +546,22 @@ set lto_link_elf_tests [list \
    {} \
    "pr31956b" \
   ] \
+  [list \
+   "PR ld/31956 (malloc)" \
+   "-Wl,--wrap=malloc" \
+   "-O2 -flto" \
+   {pr31956c.c} \
+   {} \
+   "pr31956c" \
+  ] \
+  [list \
+   "PR ld/31956 (unused)" \
+   "-Wl,--wrap=parse_line" \
+   "-O2 -flto" \
+   {pr31956d.c} \
+   {{"nm" {} "pr31956d.d"}} \
+   "pr31956d" \
+  ] \
   [list \
    "Build pr30281.so" \
    "-shared -Wl,--version-script,pr30281.t \
diff --git a/ld/testsuite/ld-plugin/pr31956c.c b/ld/testsuite/ld-plugin/pr31956c.c
new file mode 100644
index 00000000000..4a46b2b49a8
--- /dev/null
+++ b/ld/testsuite/ld-plugin/pr31956c.c
@@ -0,0 +1,19 @@
+#include <stdlib.h>
+
+extern void *__real_malloc (size_t);
+
+void *
+__wrap_malloc (size_t n)
+{
+  if (n == 0)
+    return NULL;
+  else
+    return __real_malloc (n);
+};
+
+int
+main (void)
+{
+  void *ptr = malloc (30);
+  return ptr == NULL ? 1 : 0;
+}
diff --git a/ld/testsuite/ld-plugin/pr31956d.c b/ld/testsuite/ld-plugin/pr31956d.c
new file mode 100644
index 00000000000..cb7f2d50643
--- /dev/null
+++ b/ld/testsuite/ld-plugin/pr31956d.c
@@ -0,0 +1,7 @@
+void __wrap_parse_line(void) {};
+
+int
+main (void)
+{
+  return 0;
+}
diff --git a/ld/testsuite/ld-plugin/pr31956d.d b/ld/testsuite/ld-plugin/pr31956d.d
new file mode 100644
index 00000000000..b579cdc7353
--- /dev/null
+++ b/ld/testsuite/ld-plugin/pr31956d.d
@@ -0,0 +1,4 @@
+#failif
+#...
+[0-9a-f]+ T .*parse_line
+#...