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| author | Iain Sandoe <iain@sandoe.co.uk> | 2019-10-15 20:28:02 +0000 |
|---|---|---|
| committer | Iain Sandoe <iains@gcc.gnu.org> | 2019-10-15 20:28:02 +0000 |
| commit | a1f37c3f62acf98aa2a44b1f5b3e6d574ef52670 (patch) | |
| tree | 078076731ea90c0797ca07d431a163a5646c75df | |
| parent | 6eee515142568bf25e0d99882bdf3cf5f49e97ec (diff) | |
| download | gcc-a1f37c3f62acf98aa2a44b1f5b3e6d574ef52670.zip gcc-a1f37c3f62acf98aa2a44b1f5b3e6d574ef52670.tar.gz gcc-a1f37c3f62acf98aa2a44b1f5b3e6d574ef52670.tar.bz2 | |
[Darwin] Clarify fix and continue support (NFC).
This updates the description of the support for fix and continue
debugging.
gcc/ChangeLog:
2019-10-15 Iain Sandoe <iain@sandoe.co.uk>
* config/darwin.c: Update description of fix and continue.
From-SVN: r277010
| -rw-r--r-- | gcc/ChangeLog | 4 | ||||
| -rw-r--r-- | gcc/config/darwin.c | 30 |
2 files changed, 22 insertions, 12 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 6a9c2e0..2320abc 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,5 +1,9 @@ 2019-10-15 Iain Sandoe <iain@sandoe.co.uk> + * config/darwin.c: Update description of fix and continue. + +2019-10-15 Iain Sandoe <iain@sandoe.co.uk> + * config/darwin.c (darwin_binds_local_p): Update to call default_binds_local_p_3 () directly. amend comments. diff --git a/gcc/config/darwin.c b/gcc/config/darwin.c index d34b003..c0fafed 100644 --- a/gcc/config/darwin.c +++ b/gcc/config/darwin.c @@ -49,18 +49,24 @@ along with GCC; see the file COPYING3. If not see #include "intl.h" #include "optabs.h" -/* Darwin supports a feature called fix-and-continue, which is used - for rapid turn around debugging. When code is compiled with the - -mfix-and-continue flag, two changes are made to the generated code - that allow the system to do things that it would normally not be - able to do easily. These changes allow gdb to load in - recompilation of a translation unit that has been changed into a - running program and replace existing functions and methods of that - translation unit with versions of those functions and methods - from the newly compiled translation unit. The new functions access - the existing static symbols from the old translation unit, if the - symbol existed in the unit to be replaced, and from the new - translation unit, otherwise. +/* Fix and Continue. + + NOTES: + 1) this facility requires suitable support from a modified version + of GDB, which is not provided on any system after MacOS 10.7/Darwin11. + 2) There is no support for this in any X86 version of the FSF compiler. + + Fix and continue was used on some earlier MacOS systems for rapid turn + around debugging. When code is compiled with the -mfix-and-continue + flag, two changes are made to the generated code that allow the system + to do things that it would normally not be able to do easily. These + changes allow gdb to load in recompilation of a translation unit that + has been changed into a running program and replace existing functions + and methods of that translation unit with versions of those functions + and methods from the newly compiled translation unit. The new functions + access the existing static symbols from the old translation unit, if the + symbol existed in the unit to be replaced, and from the new translation + unit, otherwise. The changes are to insert 5 nops at the beginning of all functions and to use indirection to get at static symbols. The 5 nops |