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PING Re: [patch] PR debug/46102 Disable -feliminate-dwarf2-dups when reading a PCH


On 02/19/2015 10:41 AM, Jakub Jelinek wrote:
On Thu, Feb 19, 2015 at 10:33:20AM -0800, Aldy Hernandez wrote:
Well, any PCH file we generate will have some sort of early DIE in it (at
the very least the compilation unit DIE) and we will read these in at PCH
read-in time, obliterating whatever was already there.  But most
importantly, with the attached patch we will not use these
DW_TAG_GNU_[BE]INCL* DIEs, since the reader will avoid reading the pch file.
So, I don't think erroring out at output time is necessary.

How does this look?

Looks reasonable to me, but I'd prefer to defer this to Jason as debug
maintainer.

commit d90a408ad21aa0868cc13de24ea38e210ef78a68
Author: Aldy Hernandez <aldyh@redhat.com>
Date:   Thu Feb 19 07:35:59 2015 -0800

     	PR debug/46102
     	* c-pch.c (c_common_valid_pch): Mark PCH file with
     	-feliminate-dwarf2-dups as invalid.

diff --git a/gcc/c-family/c-pch.c b/gcc/c-family/c-pch.c
index 0ede92a..55163c9 100644
--- a/gcc/c-family/c-pch.c
+++ b/gcc/c-family/c-pch.c
@@ -224,6 +224,19 @@ c_common_valid_pch (cpp_reader *pfile, const char *name, int fd)
    const char *pch_ident;
    struct c_pch_validity v;

+  /* We may have outputted a few DIEs corresponding to
+     DW_TAG_GNU_[BE]INCL.  Reading the compiler state later will read
+     in these DIEs, and obliterate any DW_TAG_GNU_[BE]INCL the reader
+     may have generated itself.  Do not read the PCH if this may
+     happen.  */
+  if (flag_eliminate_dwarf2_dups)
+    {
+      if (cpp_get_options (pfile)->warn_invalid_pch)
+	cpp_error (pfile, CPP_DL_WARNING,
+		   "%s: cannot be used with -feliminate-dwarf2-dups", name);
+      return 2;
+    }
+
    /* Perform a quick test of whether this is a valid
       precompiled header for the current language.  */



	Jakub



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