From 1b08ada61e0704c540256cb263b061af5322f1cc Mon Sep 17 00:00:00 2001 From: Mark Wielaard Date: Wed, 25 Apr 2018 17:34:00 +0000 Subject: [PATCH] DWARF sort longer dirs before shorter ones in directory table. When gcc dwarf2out generates the .debug_line table itself (for example when generating one for a split DWARF .dwo) it uses natural sorting for the directory table. Shorter directory paths come before longer directory paths with the same prefix. This causes the files in the line table to pick the shorter dir. Creating slightly ineffecient line tables because the longer directory paths will never be used. Fix this by changing file_info_cmp () to pick longer directory prefixes before shorter ones. We still sort files (the compilation unit) without any directory path before all entries with a directory path, so they will still use dir entry 0 (the working directory). A hello.c program would get the following dir and line table before: Directory table: /opt/local/install/gcc/lib/gcc/x86_64-pc-linux-gnu/8.0.1/include /usr/include /usr/include/bits File name table: Entry Dir Time Size Name 1 0 0 0 hello.c 2 1 0 0 stddef.h 3 2 0 0 bits/types.h 4 2 0 0 libio.h 5 2 0 0 stdio.h 6 2 0 0 bits/sys_errlist.h Note that the last directory table entry is never used. After this patch it looks as follows: Directory table: /opt/local/install/gcc/lib/gcc/x86_64-pc-linux-gnu/8.0.1/include /usr/include/bits /usr/include File name table: Entry Dir Time Size Name 1 0 0 0 hello.c 2 1 0 0 stddef.h 3 2 0 0 types.h 4 3 0 0 libio.h 5 3 0 0 stdio.h 6 2 0 0 sys_errlist.h Which is similar to what gas would output. gcc/ChangeLog: * dwarf2out.c (file_info_cmp): Sort longer dir prefixes before shorter ones. From-SVN: r259655 --- gcc/ChangeLog | 5 +++++ gcc/dwarf2out.c | 11 +++++++---- 2 files changed, 12 insertions(+), 4 deletions(-) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 8640e2e6af7..f00fdd8c0a3 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,8 @@ +2018-04-25 Mark Wielaard + + * dwarf2out.c (file_info_cmp): Sort longer dir prefixes before + shorter ones. + 2018-04-25 Jakub Jelinek * config/i386/i386.md (*x86_movcc_0_m1): Use type "alu1" rather diff --git a/gcc/dwarf2out.c b/gcc/dwarf2out.c index 620e66986be..d3d925d5279 100644 --- a/gcc/dwarf2out.c +++ b/gcc/dwarf2out.c @@ -11955,7 +11955,9 @@ file_info_cmp (const void *p1, const void *p2) we return consistent values to qsort since some will get confused if we return the same value when identical operands are passed in opposite orders. So if neither has a directory, return 0 and otherwise return - 1 or -1 depending on which one has the directory. */ + 1 or -1 depending on which one has the directory. We want the one with + the directory to sort after the one without, so all no directory files + are at the start (normally only the compilation unit file). */ if ((s1->path == s1->fname || s2->path == s2->fname)) return (s2->path == s2->fname) - (s1->path == s1->fname); @@ -11966,11 +11968,12 @@ file_info_cmp (const void *p1, const void *p2) { ++cp1; ++cp2; - /* Reached the end of the first path? If so, handle like above. */ + /* Reached the end of the first path? If so, handle like above, + but now we want longer directory prefixes before shorter ones. */ if ((cp1 == (const unsigned char *) s1->fname) || (cp2 == (const unsigned char *) s2->fname)) - return ((cp2 == (const unsigned char *) s2->fname) - - (cp1 == (const unsigned char *) s1->fname)); + return ((cp1 == (const unsigned char *) s1->fname) + - (cp2 == (const unsigned char *) s2->fname)); /* Character of current path component the same? */ else if (*cp1 != *cp2) -- 2.30.2