[newlib-cygwin] Cygwin: Use two pass parse for tlsoffsets generation.

[Takashi Yano]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=1559f7f4581832f05339b950fc7c82a8c98a9e0f

commit 1559f7f4581832f05339b950fc7c82a8c98a9e0f
Author: Takashi Yano <takashi.yano@nifty.ne.jp>
Date:   Thu May 19 02:51:46 2022 +0900

    Cygwin: Use two pass parse for tlsoffsets generation.
    
    - The commit "Cygwin: fix new sigfe.o generation in optimized case"
      fixed the wrong tlsoffsets generation by adding -O0 to compile
      options. Current gentls_offsets expects entry of "start_offset"
      is the first entry in the assembler code. However, without -O0,
      entry of "start_offset" goes to the last entry for some reason.
      Currently, -O0 can prevents assembler code from reversing the
      order of the entries, however, there is no guarantee that it will
      retain the order of the entries in the future.
    
      This patch makes gentls_offsets parse the assembler code in the
      two pass to omit -O0 option dependency.

Diff:
---
 winsup/cygwin/gentls_offsets | 27 ++++++++++++++++++++++-----
 1 file changed, 22 insertions(+), 5 deletions(-)

diff --git a/winsup/cygwin/gentls_offsets b/winsup/cygwin/gentls_offsets
index d76562c05..0adb702a3 100755
--- a/winsup/cygwin/gentls_offsets
+++ b/winsup/cygwin/gentls_offsets
@@ -2,6 +2,9 @@
 #set -x
 input_file=$1
 output_file=$2
+tmp_file=/tmp/${output_file}.$$
+
+trap "rm -f ${tmp_file}" 0 1 2 15
 
 # Preprocess cygtls.h and filter out only the member lines from
 # class _cygtls to generate an input file for the cross compiler
@@ -43,7 +46,7 @@ gawk '
   }
 ' | \
 # Now run the compiler to generate an assembler file.
-${CXXCOMPILE} -x c++ -g0 -O0 -S - -o - | \
+${CXXCOMPILE} -x c++ -g0 -S - -o ${tmp_file} && \
 # The assembler file consists of lines like these:
 #
 #   __CYGTLS__foo
@@ -52,10 +55,25 @@ ${CXXCOMPILE} -x c++ -g0 -O0 -S - -o - | \
 #       .align 4
 #
 # From this info, generate the tlsoffsets file.
-gawk '\
+start_offset=$(gawk '\
+  BEGIN {
+    varname=""
+  }
+  /^__CYGTLS__/ {
+    varname = gensub (/__CYGTLS__(\w+):/, "\\1", "g");
+  }
+  /\s*\.long\s+/ {
+    if (length (varname) > 0) {
+      if (varname == "start_offset") {
+	print $2;
+      }
+      varname = "";
+    }
+  }
+' ${tmp_file}) && \
+gawk -v start_offset="$start_offset" '\
   BEGIN {
     varname=""
-    start_offset = 0
   }
   /^__CYGTLS__/ {
     varname = gensub (/__CYGTLS__(\w+):/, "\\1", "g");
@@ -70,7 +88,6 @@ gawk '\
   /\s*\.long\s+/ {
     if (length (varname) > 0) {
       if (varname == "start_offset") {
-      	start_offset = $2;
 	printf (".equ _cygtls.%s, -%u\n", varname, start_offset);
       } else {
       	value = $2;
@@ -80,4 +97,4 @@ gawk '\
       varname = "";
     }
   }
-' > "${output_file}"
+' ${tmp_file} > "${output_file}"