Commit Graph

5 Commits

Author SHA1 Message Date
Fangrui Song 92b5b980d2 [ELF] Postpone evaluation of ORIGIN/LENGTH in a MEMORY command
```
createFiles(args)
 readDefsym
 readerLinkerScript(*mb)
  ...
   readMemory
    readMemoryAssignment("ORIGIN", "org", "o") // eagerly evaluated
target = getTarget();
link(args)
 writeResult<ELFT>()
  ...
   finalizeSections()
    script->processSymbolAssignments()
     addSymbol(cmd) // with this patch, evaluated here
```

readMemoryAssignment eagerly evaluates ORIGIN/LENGTH and returns an uint64_t.
This patch postpones the evaluation to make

* --defsym and symbol assignments
* `CONSTANT(COMMONPAGESIZE)` (requires a non-null `lld:🧝:target`)

work. If the expression somehow requires interaction with memory
regions, the circular dependency may cause the expression to evaluate to
a strange value. See the new test added to memory-err.s

Reviewed By: grimar

Differential Revision: https://reviews.llvm.org/D75763
2020-03-09 08:31:41 -07:00
Fangrui Song 7b8341b257 [ELF][test] Improve MEMORY tests 2020-03-06 14:01:20 -08:00
Fangrui Song 81cebfd008 [ELF][test] Change -o %t to -o /dev/null if the output is not needed 2020-02-12 21:54:50 -08:00
George Rimar 7e5b0a5978 [ELF] - Don't segfault when accessing location counter inside MEMORY command.
We would previously crash on next script:
MEMORY { name : ORIGIN = .; }

Patch fixes that.

Differential revision: https://reviews.llvm.org/D36138

llvm-svn: 311073
2017-08-17 08:47:21 +00:00
George Rimar 5fb17128f7 [ELF] - Do not segfault if linkerscript tries to access Target too early.
Following possible scripts triggered accessing to Target when it was not yet
initialized (was nullptr).

MEMORY { name : ORIGIN = DATA_SEGMENT_RELRO_END; }
MEMORY { name : ORIGIN = CONSTANT(COMMONPAGESIZE); }

Patch errors out instead.

Differential revision: https://reviews.llvm.org/D36140

llvm-svn: 309953
2017-08-03 16:05:08 +00:00