[PATCH] D55800: [ELF] Place .note in the first page to ensure they are available in core files
Fangrui Song via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Mon Dec 17 17:38:08 PST 2018
MaskRay updated this revision to Diff 178571.
MaskRay edited the summary of this revision.
MaskRay added a comment.
gold
Repository:
rLLD LLVM Linker
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D55800/new/
https://reviews.llvm.org/D55800
Files:
ELF/Writer.cpp
Index: ELF/Writer.cpp
===================================================================
--- ELF/Writer.cpp
+++ ELF/Writer.cpp
@@ -729,9 +729,10 @@
// * It is easy to check if a give branch was taken.
// * It is easy two see how similar two ranks are (see getRankProximity).
enum RankFlags {
- RF_NOT_ADDR_SET = 1 << 18,
+ RF_NOT_ADDR_SET = 1 << 19,
+ RF_NOT_ALLOC = 1 << 18,
RF_NOT_INTERP = 1 << 17,
- RF_NOT_ALLOC = 1 << 16,
+ RF_NOT_NOTE = 1 << 16,
RF_WRITE = 1 << 15,
RF_EXEC_WRITE = 1 << 14,
RF_EXEC = 1 << 13,
@@ -759,17 +760,25 @@
return Rank;
Rank |= RF_NOT_ADDR_SET;
- // Put .interp first because some loaders want to see that section
- // on the first page of the executable file when loaded into memory.
- if (Sec->Name == ".interp")
- return Rank;
- Rank |= RF_NOT_INTERP;
-
// Allocatable sections go first to reduce the total PT_LOAD size and
// so debug info doesn't change addresses in actual code.
if (!(Sec->Flags & SHF_ALLOC))
return Rank | RF_NOT_ALLOC;
+ // Put .interp first because some loaders want to see that section
+ // on the first page of the executable file when loaded into memory.
+ if (Sec->Name == ".interp")
+ return Rank;
+ Rank |= RF_NOT_INTERP;
+
+ // Put allocatable .note next because they contain information (e.g.
+ // .note.gnu.build-id identifies the origin of the core) useful in core files.
+ // This ensures they are always dumped (at least on Linux) because they are in
+ // the first page.
+ if (Sec->Type == SHT_NOTE)
+ return Rank;
+ Rank |= RF_NOT_NOTE;
+
// Sort sections based on their access permission in the following
// order: R, RX, RWX, RW. This order is based on the following
// considerations:
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