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| author | Fangrui Song <[email protected]> | 2019-09-16 07:44:05 -0700 |
|---|---|---|
| committer | Fangrui Song <[email protected]> | 2019-09-21 17:55:14 -0700 |
| commit | 7f044341f9f5c227d7c13c9c8ac2e9b00c8ed287 (patch) | |
| tree | 23f8f74bdf6c3a172fde8cd6d390030aede4cb82 /doc | |
| parent | 8db7dfb5c41fcb52d1a571823147589ab2a03a6c (diff) | |
| download | mruby-7f044341f9f5c227d7c13c9c8ac2e9b00c8ed287.tar.gz mruby-7f044341f9f5c227d7c13c9c8ac2e9b00c8ed287.zip | |
Rename MRB_USE_ETEXT_EDATA to MRB_USE_LINK_TIME_RO_DATA_P and support lld linked programs
In lld linked programs, .rodata comes before .text, thus mrb_ro_data_p
will return false for strings in .rodata. Change the lower bound from
_etext to __ehdr_start to catch these cases. This works for ld.bfd, gold
and lld, and it does not have false positives even if .init_array does
not exist.
Remove the branch that uses _edata: strings in .data can be modified so
this is semantically incorrect. Delete the __APPLE__ branch (its
manpages say get_etext() and get_edata() are strongly discouraged).
.init_array has been adopted by most ELF platforms to supersede .ctors.
Neither _etext nor _edata is used, so rename MRB_USE_ETEXT_EDATA to
MRB_USE_EHDR_START.
Diffstat (limited to 'doc')
| -rw-r--r-- | doc/guides/mrbconf.md | 17 |
1 files changed, 6 insertions, 11 deletions
diff --git a/doc/guides/mrbconf.md b/doc/guides/mrbconf.md index 4f5349e77..2f81776df 100644 --- a/doc/guides/mrbconf.md +++ b/doc/guides/mrbconf.md @@ -134,21 +134,16 @@ largest value of required alignment. ## Reduce heap memory configuration. -`MRB_USE_ETEXT_EDATA` +`MRB_USE_LINK_TIME_RO_DATA_P` +* Only available on ELF platforms. * If you specify the address of a read-only section when creating a symbol or string, that string will be used as it is. * Heap memory can be saved. -* Uses `_etext` and `__init_array_start`. -* It must be `_etext < data_addr < &__init_array_start`. - -`MRB_NO_INIT_ARRAY_START` -* Ignored if `MRB_USE_ETEXT_EDATA` is not defined. -* Please try if `__init_array_start` is not available. -* Uses `_etext` and `_edata`. -* It must be `_etext < data_addr < _edata`. +* Uses `__ehdr_start` and `__init_array_start`. +* It must be `__ehdr_start < data_addr < __init_array_start`. `MRB_USE_CUSTOM_RO_DATA_P` -* Takes precedence over `MRB_USE_ETEXT_EDATA`. -* Please try if both `MRB_USE_ETEXT_EDATA` and `MRB_NO_INIT_ARRAY_START` are not available. +* Takes precedence over `MRB_USE_LINK_TIME_RO_DATA_P`. +* Please try if `MRB_USE_LINK_TIME_RO_DATA_P` is not available. * The `mrb_ro_data_p()` function is implemented by the user in an arbitrary file. * The prototype declaration is `mrb_bool mrb_ro_data_p(const char *ptr)`. * Return `TRUE` if `ptr` is in read-only section, otherwise return `FALSE`. |