All iOS arm processor support switching between arm and thumb mode at call sites
by using the BLX instruction (instead of BL). But the compiler does not know
the implementation mode for extern functions, so the linker must update BL/BLX
instructions to match what is linked is actually linked together. In addition,
pointers to functions (such as vtables) must have the low bit set if the target
of the pointer is a thumb mode function.
llvm-svn: 214140
The following expression
m[i] = m[j]
where m is a DenseMap and i != j is not safe. m[j] returns a
reference, which would be invalidated when a rehashing occurs.
If rehashing occurs to make room for m[i], m[j] becomes
invalid, and that invalid reference would be used as the RHS
value of the expression.
llvm-svn: 213969
Sometimes compilers emit data into code sections (e.g. constant pools or
jump tables). These runs of data can throw off disassemblers. The solution
in mach-o is that ranges of data-in-code are encoded into a table pointed to
by the LC_DATA_IN_CODE load command.
The way the data-in-code information is encoded into lld's Atom model is that
that start and end of each data run is marked with a Reference whose offset
is the start/end of the data run. For arm, the switch back to code also marks
whether it is thumb or arm code.
llvm-svn: 213901
insertElementAt(x, END) does the identical thing as addInputElement(x),
so the only reasonable use of insertElementAt is to call it with the
other possible argument, BEGIN. That means the second parameter of the
function is just redundant. This patch is to remove the second
parameter and rename the function accordingly.
llvm-svn: 213821
The entry point file needs to be processed after all other
object files and before all .lib files. It was processed
after .lib files. That caused an issue that the entry point
function was not resolved from the standard library files.
llvm-svn: 213804
On Windows there are four "main" functions -- main, wmain, WinMain,
or wWinMain. Their parameter types are diffferent. The standard
library provides four different entry functions (i.e.
{w,}{WinMain,main}CRTStartup) for them. You need to use the right
entry routine for your "main" function.
If you give an /entry option, the specified name is used
unconditionally.
Otherwise, the linker needs to select the right one based on
user-supplied entry point function. This can be done after the
linker reads all the input files.
This patch moves the code to determine the entry point function
from the driver to a virtual input file. It also implements the
correct logic for the entry point function selection.
llvm-svn: 213713
This patch just supports marking ranges that are thumb code (vs arm code).
Future patches will mark data and jump table ranges. The ranges are encoded
as References with offsetInAtom being the start of the range and the target
being the same atom.
llvm-svn: 213712
This is a part of a larger change to move the entry point
processing to a later pass than the driver. On Windows the default
entry point function varies depending on user-provided functions.
That means the driver is not able to correctly know the entry point
function name. Only passes after the core linker can infer it.
llvm-svn: 213697
Over time the symbols and relocations have changed for dwarf unwind info
in the __eh_frame section. Add test cases for older and new style.
llvm-svn: 213585
Add support for adding section relocations in -r mode. Enhance the test
cases which validate the parsing of .o files to also round trip. They now
write out the .o file and then parse that, verifying all relocations survived
the round trip.
llvm-svn: 213333
The code to manage resolvable symbols is now separated from
ExportedSymbolRenameFile so that other class can reuse it.
I'm planning to use it to find the entry function symbol
based on resolvable symbols.
llvm-svn: 213322
All architecture specific handling is now done in the appropriate
ArchHandler subclass.
The StubsPass and GOTPass have been simplified. All architecture specific
variations in stubs are now encoded in a table which is vended by the
current ArchHandler.
llvm-svn: 213187
There are two forms of `-l` prefixed expression:
* -l<libname>
* -l:<filename>
In the first case a linker should construct a full library name
`lib + libname + .[so|a]` and search this library as usual. In the second case
a linker should use the `<filename>` as is and search this file through library
search directories.
The patch reviewed by Shankar Easwaran.
llvm-svn: 213077
Previously we invoked cvtres.exe for each compiled Windows
resource file. The generated files were then concatenated
and embedded to the executable.
That was not the correct way to merge compiled Windows
resource files. If you just concatenate generated files,
only the first file would be recognized and the rest would
be ignored as trailing garbage.
The right way to merge them is to call cvtres.exe with
multiple input files. In this patch we do that in the
Windows driver.
llvm-svn: 212763
These behave slightly idiosyncratically in the best of cases, and have
additional hacks layered on top of that for compatibility with badly behaved
build systems (via ld64).
For -lXYZ:
+ If XYZ is actually XY.o then search all library paths for XY.o
+ Otherwise search all library paths, first for libXYZ.dylib, then libXYZ.a
+ By default the library paths are /usr/lib and /usr/local/lib in that order.
For -syslibroot:
+ -syslibroot options apply to absolute paths in the search order.
+ All -syslibroot prefixes that exist are added to the search path *instead*
of the original.
+ If no -syslibroot prefixed path exists, the original is kept.
+ Hacks^WExceptions:
+ If only 1 -syslibroot is given and doesn't contain /usr/lib or
/usr/local/lib, that path is dropped entirely. (rdar://problem/6438270).
+ If the last -syslibroot is "/", all of them are ignored entirely.
(rdar://problem/5829579).
At least, that's my best interpretation of what ld64 does in buildSearchPaths.
llvm-svn: 212706
Nick Kledzik