The main challenge was handling the different on-disk structures (e.g.
`mach_header` vs `mach_header_64`). I tried to strike a balance between
sprinkling `target->wordSize == 8` checks everywhere (branchy = slow, and ugly)
and templatizing everything (causes code bloat, also ugly). I think I struck a
decent balance by judicious use of type erasure.
Note that LLD-ELF has a similar architecture, though it seems to use more templating.
Linking chromium_framework takes about the same time before and after this
change:
N Min Max Median Avg Stddev
x 20 4.52 4.67 4.595 4.5945 0.044423204
+ 20 4.5 4.71 4.575 4.582 0.056344803
No difference proven at 95.0% confidence
Reviewed By: #lld-macho, oontvoo
Differential Revision: https://reviews.llvm.org/D99633
`class Symbol` defines a data member `InputFile *file;`
`class Defined` inherits from `Symbol` and also defines a data member `InputFile *file;` for no apparent purpose.
Differential Revision: https://reviews.llvm.org/D99783
This diff addresses FIXME in SyntheticSections.cpp and removes
the dependency of emitEndFunStab on .subsections_via_symbols.
Test plan: make check-lld-macho
Differential revision: https://reviews.llvm.org/D99054
This diff is a preparation for fixing FunStabs (incorrect size calculation).
std::map<uint32_t, InputSection*> (SubsectionMap) is replaced with
a sorted vector + binary search. If .subsections_via_symbols is set
this vector will contain the list of subsections, otherwise,
the offsets will be used for calculating the symbols sizes.
Test plan: make check-all
Differential revision: https://reviews.llvm.org/D98837
This reuses the approach (and some code) from LLD-ELF.
It's a decent win when linking chromium_framework on a Mac Pro (3.2 GHz 16-Core Intel Xeon W):
N Min Max Median Avg Stddev
x 20 4.58 4.83 4.66 4.6685 0.066591844
+ 20 4.42 4.61 4.5 4.505 0.04751731
Difference at 95.0% confidence
-0.1635 +/- 0.0370242
-3.5022% +/- 0.793064%
(Student's t, pooled s = 0.0578462)
The output binary is 381MB.
Reviewed By: #lld-macho, oontvoo
Differential Revision: https://reviews.llvm.org/D99279
The functionality was originally added in {D95265}, but the test in that
diff only checked if `-ObjC` would cause bitcode containing ObjC class
symbols to be loaded. It neglected to test for bitcode containing
categories but no class symbols.
This diff also changes the lto-archive.ll test to use `-why_load`
instead of inspecting the output binary's symbol table. This is
motivated by the stacked diff {D99105}, which will hide irrelevant
bitcode symbols.
Reviewed By: #lld-macho, oontvoo
Differential Revision: https://reviews.llvm.org/D99215
Within `lld/macho/`, only `InputFiles.cpp` and `Symbols.h` require the `macho::` namespace qualifier to disambiguate references to `class Symbol`.
Add braces to outer `for` of a 5-level single-line `if`/`for` nest.
Differential Revision: https://reviews.llvm.org/D99555
Summary: We needed to use `Joined` instead of `Flag`. This wasn't caught
because the relevant test that was copied from LLD-ELF was still
invoking LLD-ELF instead of LLD-MachO...
Differential Revision: https://reviews.llvm.org/D99313
Pretty simple code-wise. Also threw in some refactoring:
* Put the functionStartSection under Writer instead of InStruct, since
it doesn't need to be accessed outside of Writer
* Adjusted the test to put all files under the temp dir instead of at
the top-level
* Added some CHECK-LABELs to make it clearer where the function starts
data is
Differential Revision: https://reviews.llvm.org/D99112
I added just enough to allow us to see a top-level breakdown of time taken. This
is the result of loading the time-trace output into `chrome:://tracing`:
ef5e8234f3/tracing.png
Reviewed By: oontvoo
Differential Revision: https://reviews.llvm.org/D99311
In future patches I will be setting the IsText parameter frequently so I will refactor the args to be in the following order. I have removed the FileSize parameter because it is never used.
```
static ErrorOr<std::unique_ptr<MemoryBuffer>>
getFile(const Twine &Filename, bool IsText = false,
bool RequiresNullTerminator = true, bool IsVolatile = false);
static ErrorOr<std::unique_ptr<MemoryBuffer>>
getFileOrSTDIN(const Twine &Filename, bool IsText = false,
bool RequiresNullTerminator = true);
static ErrorOr<std::unique_ptr<MB>>
getFileAux(const Twine &Filename, uint64_t MapSize, uint64_t Offset,
bool IsText, bool RequiresNullTerminator, bool IsVolatile);
static ErrorOr<std::unique_ptr<WritableMemoryBuffer>>
getFile(const Twine &Filename, bool IsVolatile = false);
```
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D99182
Don't run the 'tar' tool in a cleared environment with only the
LANG variable set, just set LANG on top of the existing environment.
If the 'tar' tool is an MSYS based tool, running it in a Windows
Container hangs if all environment variables are cleared - in
particular, the USERPROFILE variable needs to be kept intact.
This is the same issue fixed as was fixed in other places in
9de63b2e05, but contrary to running
the actual tests, running with an as-cleared-as-possible environment
here is less important.
Differential Revision: https://reviews.llvm.org/D99304
This patch renames the "Initial" member of WasmLimits to the name used
in the spec, "Minimum".
In the core WebAssembly specification, the Limits data type has one
required "min" member and one optional "max" member, indicating the
minimum required size of the corresponding table or memory, and the
maximum size, if any.
Although the WebAssembly spec does instantiate locally-defined tables
and memories with the initial size being equal to the minimum size, it
can't impose such a requirement for imports. It doesn't make sense to
require an initial size for a memory import, for example. The compiler
can only sensibly express the minimum and maximum sizes.
See
https://github.com/WebAssembly/js-types/blob/master/proposals/js-types/Overview.md#naming-of-size-limits
for a related discussion that agrees that the right name of "initial" is
"minimum" when querying the type of a table or memory from JavaScript.
(Of course it still makes sense for JS to speak in terms of an initial
size when it explicitly instantiates memories and tables.)
Differential Revision: https://reviews.llvm.org/D99186
This reverts commit 4876ba5b2d.
Third-attemp relanding D98559, new change:
- explicitly cast enum to underlying type to avoid ambiguity (workaround to clang's bug).
This reverts commit 3c21166a94.
The build is broken (clang-8 host compiler):
lld/MachO/DriverUtils.cpp:271:8: error: use of overloaded operator '<<' is ambiguous (with operand types 'llvm::raw_fd_ostream' and 'lld::macho::DependencyTracker::DepOpCode')
os << opcode;
~~ ^ ~~~~~~
This reverts commit 9670d2e4af.
Second attemp to reland D98559. New changes:
- inline functions removed from cpp file.
- updated tests to use CHECK-DAG instead of CHECK-NEXT
- fixed ambiguous "<<" operator by switching `char` to uint8_t
The only known reason why ICF should not merge otherwise identical
sections with differing associated sections has to do with exception
handling tables. It's not clear what ICF should do when there are other
kinds of associated sections. In every other case when this has come up,
debug info and CF guard metadata, we have opted to make ICF ignore the
associated sections.
For comparison, ELF doesn't do anything for comdat groups. Instead,
.eh_frame is parsed to figure out if a section has an LSDA, and if so,
ICF is disabled.
Another issue is that the order of associated sections is not defined.
We have had issues in the past (crbug.com/1144476) where changing the
order of the .xdata/.pdata sections in the object file lead to large ICF
slowdowns.
To address these issues, I decided it would be best to explicitly
consider only .pdata and .xdata sections during ICF. This makes it easy
to ignore the object file order, and I think it makes the intention of
the code clearer.
I've also made the children() accessor return an empty list for
associated sections. This mostly only affects ICF and GC. This was the
behavior before I made this a linked list, so the behavior change should
be good. This had positive effects on chrome.dll: more .xdata sections
were merged that previously could not be merged because they were
associated with distinct .pdata sections.
Reviewed By: mstorsjo
Differential Revision: https://reviews.llvm.org/D98993
This reverts commit 2554b95db5.
Relanding [lld-macho] Implement -dependency_info (D98559) with changes:
- inline functions removed from cpp file.
- updated tests to not check libSystem.tbd with other input files (because of possible indeterministic ordering)
There is a bug when initial exec is relaxed to local exec.
In the following situation:
InitExec.c
```
extern __thread unsigned TGlobal;
unsigned getConst(unsigned*);
unsigned addVal(unsigned, unsigned*);
unsigned GetAddrT() {
return addVal(getConst(&TGlobal), &TGlobal);
}
```
Def.c
```
__thread unsigned TGlobal;
unsigned getConst(unsigned* A) {
return *A + 3;
}
unsigned addVal(unsigned A, unsigned* B) {
return A + *B;
}
```
The problem is in InitExec.c but Def.c is required if you want to link the example and see the problem.
To compile everything:
```
clang -O3 -mcpu=pwr10 -c InitExec.c
clang -O3 -mcpu=pwr10 -c Def.c
ld.lld InitExec.o Def.o -o IeToLe
```
If you objdump the problem object file:
```
$ llvm-objdump -dr --mcpu=pwr10 InitExec.o
```
you will get the following assembly:
```
0000000000000000 <GetAddrT>:
0: a6 02 08 7c mflr 0
4: f0 ff c1 fb std 30, -16(1)
8: 10 00 01 f8 std 0, 16(1)
c: d1 ff 21 f8 stdu 1, -48(1)
10: 00 00 10 04 00 00 60 e4 pld 3, 0(0), 1
0000000000000010: R_PPC64_GOT_TPREL_PCREL34 TGlobal
18: 14 6a c3 7f add 30, 3, 13
0000000000000019: R_PPC64_TLS TGlobal
1c: 78 f3 c3 7f mr 3, 30
20: 01 00 00 48 bl 0x20
0000000000000020: R_PPC64_REL24_NOTOC getConst
24: 78 f3 c4 7f mr 4, 30
28: 30 00 21 38 addi 1, 1, 48
2c: 10 00 01 e8 ld 0, 16(1)
30: f0 ff c1 eb ld 30, -16(1)
34: a6 03 08 7c mtlr 0
38: 00 00 00 48 b 0x38
0000000000000038: R_PPC64_REL24_NOTOC addVal
```
The lines of interest are:
```
10: 00 00 10 04 00 00 60 e4 pld 3, 0(0), 1
0000000000000010: R_PPC64_GOT_TPREL_PCREL34 TGlobal
18: 14 6a c3 7f add 30, 3, 13
0000000000000019: R_PPC64_TLS TGlobal
1c: 78 f3 c3 7f mr 3, 30
```
Which once linked gets turned into:
```
10010210: ff ff 03 06 00 90 6d 38 paddi 3, 13, -28672, 0
10010218: 00 00 00 60 nop
1001021c: 78 f3 c3 7f mr 3, 30
```
The problem is that register 30 is never set after the optimization.
Therefore it is not correct to relax the above instructions by replacing
the add instruction with a nop.
Instead the add instruction should be replaced with a copy (mr) instruction.
If the add uses the same resgiter as input and as ouput then it is safe to
continue to replace the add with a nop.
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D95262
This reverts commit c53a1322f3.
Test only passes depending on build dir having a lexicographically later name
than the source dir, and doesn't link on mac/win. See
https://reviews.llvm.org/D98559#2640265 onward.
Bug: https://bugs.llvm.org/show_bug.cgi?id=49278
The flag is not well documented, so this implementation is based on observed behaviour.
When specified, `-dependency_info <path>` produced a text file containing information pertaining to the current linkage, such as input files, output file, linker version, etc.
This file's layout is also not documented, but it seems to be a series of null ('\0') terminated strings in the form `<op code><path>`
`<op code>` could be:
`0x00` : linker version
`0x10` : input
`0x11` : files not found(??)
`0x40` : output
`<path>` : is the file path, except for the linker-version case.
(??) This part is a bit unclear. I think it means all the files the linker attempted to look at, but could not find.
Differential Revision: https://reviews.llvm.org/D98559
Nico Weber
