293 Commits

Author SHA1 Message Date
Eric Christopher
bf9b77d2fa Tidy up logic around unique section name creation and remove a
mostly unused variable.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@338468 91177308-0d34-0410-b5e6-96231b3b80d8
2018-08-01 01:03:34 +00:00
Martin Storsjo
078cc9c528 Revert "[COFF] Use comdat shared constants for MinGW as well"
This reverts commit r337951.

While that kind of shared constant generally works fine in a MinGW
setting, it broke some cases of inline assembly that worked before:

$ cat const-asm.c
int MULH(int a, int b) {
    int rt, dummy;
    __asm__ (
        "imull %3"
        :"=d"(rt), "=a"(dummy)
        :"a"(a), "rm"(b)
    );
    return rt;
}
int func(int a) {
    return MULH(a, 1);
}
$ clang -target x86_64-win32-gnu -c const-asm.c -O2
const-asm.c:4:9: error: invalid variant '00000001'
        "imull %3"
        ^
<inline asm>:1:15: note: instantiated into assembly here
        imull __real@00000001(%rip)
                     ^

A similar error is produced for i686 as well. The same test with a
target of x86_64-win32-msvc or i686-win32-msvc works fine.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@338018 91177308-0d34-0410-b5e6-96231b3b80d8
2018-07-26 10:48:20 +00:00
Martin Storsjo
f2f6b9cfe0 [COFF] Use comdat shared constants for MinGW as well
GNU binutils tools have no problems with this kind of shared constants,
provided that we actually hook it up completely in AsmPrinter and
produce a global symbol.

This effectively reverts SVN r335918 by hooking the rest of it up
properly.

This feature was implemented originally in SVN r213006, with no reason
for why it can't be used for MinGW other than the fact that GCC doesn't
do it while MSVC does.

Differential Revision: https://reviews.llvm.org/D49646

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@337951 91177308-0d34-0410-b5e6-96231b3b80d8
2018-07-25 18:35:42 +00:00
Martin Storsjo
ae3e2f0243 [MC] Add a separate flag for skipping comdat constant sections for MinGW. NFC.
This actually has nothing to do with the associative comdat sections
that aren't supported by GNU binutils ld.

Clarify the comments from SVN r335918 and use a separate flag for it.

Differential Revision: https://reviews.llvm.org/D49645

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@337757 91177308-0d34-0410-b5e6-96231b3b80d8
2018-07-23 22:15:25 +00:00
Michael J. Spencer
3da6ce5ebe Recommit r335794 "Add support for generating a call graph profile from Branch Frequency Info." with fix for removed functions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@337140 91177308-0d34-0410-b5e6-96231b3b80d8
2018-07-16 00:28:24 +00:00
Martin Storsjo
d628d72dc9 [COFF] Fix constant sharing regression for MinGW
This fixes a regression since SVN r334523, where the object files
built targeting MinGW were rejected by GNU binutils tools. Prior to
that commit, we only put constants in comdat for MSVC configurations.

Differential Revision: https://reviews.llvm.org/D48567

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@335918 91177308-0d34-0410-b5e6-96231b3b80d8
2018-06-28 20:28:29 +00:00
Benjamin Kramer
1bbef2cc89 Revert "Add support for generating a call graph profile from Branch Frequency Info."
This reverts commits r335794 and r335797. Breaks ThinLTO+FDO selfhost.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@335851 91177308-0d34-0410-b5e6-96231b3b80d8
2018-06-28 13:15:03 +00:00
Michael J. Spencer
71b21d8fcc Add support for generating a call graph profile from Branch Frequency Info.
=== Generating the CG Profile ===

The CGProfile module pass simply gets the block profile count for each BB and scans for call instructions.  For each call instruction it adds an edge from the current function to the called function with the current BB block profile count as the weight.

After scanning all the functions, it generates an appending module flag containing the data. The format looks like:
```
!llvm.module.flags = !{!0}

!0 = !{i32 5, !"CG Profile", !1}
!1 = !{!2, !3, !4} ; List of edges
!2 = !{void ()* @a, void ()* @b, i64 32} ; Edge from a to b with a weight of 32
!3 = !{void (i1)* @freq, void ()* @a, i64 11}
!4 = !{void (i1)* @freq, void ()* @b, i64 20}
```

Differential Revision: https://reviews.llvm.org/D48105

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@335794 91177308-0d34-0410-b5e6-96231b3b80d8
2018-06-27 23:58:08 +00:00
Chandler Carruth
8e0778c059 Revert r335306 (and r335314) - the Call Graph Profile pass.
This is the first pass in the main pipeline to use the legacy PM's
ability to run function analyses "on demand". Unfortunately, it turns
out there are bugs in that somewhat-hacky approach. At the very least,
it leaks memory and doesn't support -debug-pass=Structure. Unclear if
there are larger issues or not, but this should get the sanitizer bots
back to green by fixing the memory leaks.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@335320 91177308-0d34-0410-b5e6-96231b3b80d8
2018-06-22 05:33:57 +00:00
Michael J. Spencer
3499852bee [Instrumentation] Add Call Graph Profile pass
This patch adds support for generating a call graph profile from Branch Frequency Info.

The CGProfile module pass simply gets the block profile count for each BB and scans for call instructions. For each call instruction it adds an edge from the current function to the called function with the current BB block profile count as the weight.

After scanning all the functions, it generates an appending module flag containing the data. The format looks like:

!llvm.module.flags = !{!0}

!0 = !{i32 5, !"CG Profile", !1}
!1 = !{!2, !3, !4} ; List of edges
!2 = !{void ()* @a, void ()* @b, i64 32} ; Edge from a to b with a weight of 32
!3 = !{void (i1)* @freq, void ()* @a, i64 11}
!4 = !{void (i1)* @freq, void ()* @b, i64 20}

Differential Revision: https://reviews.llvm.org/D48105

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@335306 91177308-0d34-0410-b5e6-96231b3b80d8
2018-06-21 23:31:10 +00:00
Reid Kleckner
b9c0a17b9f [X86] Fix 32-bit mingw comdat names, only add one underscore
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@335304 91177308-0d34-0410-b5e6-96231b3b80d8
2018-06-21 23:06:33 +00:00
Reid Kleckner
845b439bb4 [mingw] Fix GCC ABI compatibility for comdat things
Summary:
GCC and the binutils COFF linker do comdats differently from MSVC.
If we want to be ABI compatible, we have to do what they do, which is to
emit unique section names like ".text$_Z3foov" instead of short section
names like ".text". Otherwise, the binutils linker gets confused and
reports multiple definition errors when two object files from GCC and
Clang containing the same inline function are linked together.

The best description of the issue is probably at
https://github.com/Alexpux/MINGW-packages/issues/1677, we don't seem to
have a good one in our tracker.

I fixed up the .pdata and .xdata sections needed everywhere other than
32-bit x86. GCC doesn't use associative comdats for those, it appears to
rely on the section name.

Reviewers: smeenai, compnerd, mstorsjo, martell, mati865

Subscribers: llvm-commits, hiraditya

Differential Revision: https://reviews.llvm.org/D48402

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@335286 91177308-0d34-0410-b5e6-96231b3b80d8
2018-06-21 20:27:38 +00:00
Eric Christopher
54da16e23f Add some explanatory text to the associated symbol support.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@335207 91177308-0d34-0410-b5e6-96231b3b80d8
2018-06-21 07:15:14 +00:00
Sam Clegg
10cde000da [WebAssembly] Ignore explicit section names for functions
WebAssembly doesn't support more than one function per section
and we rely on function sections being unique. This change ignores
the section provided by the function to avoid two functions being
in the same section.

Without this change the object writer produces the following
error for this test:
 LLVM ERROR: section already has a defining function: baz

Differential Revision: https://reviews.llvm.org/D48178

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@334752 91177308-0d34-0410-b5e6-96231b3b80d8
2018-06-14 18:48:19 +00:00
Reid Kleckner
ff373df179 [MS][ARM64] Hoist __ImageBase handling into TargetLoweringObjectFileCOFF
All COFF targets should use @IMGREL32 relocations for symbol differences
against __ImageBase. Do the same for getSectionForConstant, so that
immediates lowered to globals get merged across TUs.

Patch by Chris January

Differential Revision: https://reviews.llvm.org/D47783

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@334523 91177308-0d34-0410-b5e6-96231b3b80d8
2018-06-12 18:56:05 +00:00
Eric Christopher
3de2740e68 Tidy comment up a bit.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@332687 91177308-0d34-0410-b5e6-96231b3b80d8
2018-05-18 02:39:57 +00:00
Eric Christopher
bc809c37df Fix small grammar-o.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@332522 91177308-0d34-0410-b5e6-96231b3b80d8
2018-05-16 20:34:00 +00:00
Eric Christopher
26c5a9605f Remove unused argument from emitModuleMetadata.
NFCI.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@330470 91177308-0d34-0410-b5e6-96231b3b80d8
2018-04-20 19:07:57 +00:00
Steven Wu
bba7686b46 [MachO] Emit Weak ReadOnlyWithRel to ConstDataSection
Summary:
Darwin dynamic linker can handle weak symbols in ConstDataSection.
ReadonReadOnlyWithRel symbols should be emitted in ConstDataSection
instead of normal DataSection.

rdar://problem/39298457

Reviewers: dexonsmith, kledzik

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D45472

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@329752 91177308-0d34-0410-b5e6-96231b3b80d8
2018-04-10 20:16:35 +00:00
Saleem Abdulrasool
e7676fec11 CodeGen: support an extension to pass linker options on ELF
Introduce an extension to support passing linker options to the linker.
These would be ignored by older linkers, but newer linkers which support
this feature would be able to process the linker.

Emit a special discarded section `.linker-option`.  The content of this
section is a pair of strings (key, value).  The key is a type identifier for
the parameter.  This allows for an argument free parameter that will be
processed by the linker with the value being the parameter.  As an example,
`lib` identifies a library to be linked against, traditionally the `-l`
argument for Unix-based linkers with the parameter being the library name.

Thanks to James Henderson, Cary Coutant, Rafael Espinolda, Sean Silva
for the valuable discussion on the design of this feature.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@323783 91177308-0d34-0410-b5e6-96231b3b80d8
2018-01-30 16:29:29 +00:00
Saleem Abdulrasool
860652c3f8 CodeGen: handle llvm.used properly for COFF
`llvm.used` contains a list of pointers to named values which the
compiler, assembler, and linker are required to treat as if there is a
reference that they cannot see.  Ensure that the symbols are preserved
by adding an explicit `-include` reference to the linker command.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@323017 91177308-0d34-0410-b5e6-96231b3b80d8
2018-01-20 00:28:02 +00:00
Sam Clegg
e92250ac8f [WebAssembly] Add COMDAT support
This adds COMDAT support to the Wasm object-file format.
Spec: https://github.com/WebAssembly/tool-conventions/pull/31

Corresponding LLD change:
https://bugs.llvm.org/show_bug.cgi?id=35533, and D40845

Patch by Nicholas Wilson

Differential Revision: https://reviews.llvm.org/D40844

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@322135 91177308-0d34-0410-b5e6-96231b3b80d8
2018-01-09 23:43:14 +00:00
Sam Clegg
5334180cf2 [WebAssembly] Implement @llvm.global_ctors and @llvm.global_dtors
Summary:
- lowers @llvm.global_dtors by adding @llvm.global_ctors
  functions which register the destructors with `__cxa_atexit`.
- impements @llvm.global_ctors with wasm start functions and linker metadata

See [here](https://github.com/WebAssembly/tool-conventions/issues/25) for more background.

Subscribers: jfb, dschuff, mgorny, jgravelle-google, aheejin, sunfish

Differential Revision: https://reviews.llvm.org/D41211

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@320774 91177308-0d34-0410-b5e6-96231b3b80d8
2017-12-15 00:17:10 +00:00
Sam Clegg
9310123e7f [WebAssembly] section kind can be code
Currently, when creating a named section, the Wasm
frontend forces it to use `SectionKind::Data`, whereas
in fact C++ does generate code sections with custom
names.

Patch by Nicholas Wilson

Differential Revision: https://reviews.llvm.org/D40906

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@320002 91177308-0d34-0410-b5e6-96231b3b80d8
2017-12-07 02:55:51 +00:00
Martin Storsjo
9ab4c272cb [COFF] Implement constructor priorities
The priorities in the section name suffixes are zero padded,
allowing the linker to just do a lexical sort.

Add zero padding for .ctors sections in ELF as well.

Differential Revision: https://reviews.llvm.org/D40407

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@319150 91177308-0d34-0410-b5e6-96231b3b80d8
2017-11-28 08:07:18 +00:00
Fangrui Song
0b5d88f3e0 NFC Remove default argument of DataLayout::getPointerABIAlignment
Differential Revision: https://reviews.llvm.org/D40005

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@318272 91177308-0d34-0410-b5e6-96231b3b80d8
2017-11-15 06:17:32 +00:00
Sam Clegg
336b4883e2 [WebAssembly] Explicily disable comdat support for wasm output
For now at least.  We clearly need some kind of comdat or
linkonce_odr support for wasm but currently COMDAT is not
supported.

Disable COMDAT support in the same way we do the Mach-O.  This
also causes clang not to generated COMDATs.

Differential Revision: https://reviews.llvm.org/D39873

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@318123 91177308-0d34-0410-b5e6-96231b3b80d8
2017-11-14 00:49:16 +00:00
Sam Clegg
2b6b6ac523 [WebAssembly] MC: Fix crash when -g specified.
At this point we don't output any debug sections or thier
relocations.

Differential Revision: https://reviews.llvm.org/D39076

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@316240 91177308-0d34-0410-b5e6-96231b3b80d8
2017-10-20 21:28:38 +00:00
Sam Clegg
7fa3570b3b [WebAssembly] MC: Support for init_array and fini_array
Differential Revision: https://reviews.llvm.org/D37757

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@314783 91177308-0d34-0410-b5e6-96231b3b80d8
2017-10-03 11:20:28 +00:00
Sam Clegg
a9217f66bf [WebAssembly] MC: Create wasm data segments based on MCSections
This means that we can honor -fdata-sections rather than
always creating a segment for each symbol.

It also allows for a followup change to add .init_array and friends.

Differential Revision: https://reviews.llvm.org/D37876

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@313395 91177308-0d34-0410-b5e6-96231b3b80d8
2017-09-15 20:54:59 +00:00
Sam Clegg
c6a7215922 [WebAssembly] Remove flags from MCSectionWasm
Looks like these were copied from the ELF sections but
don't apply to Wasm and were not used anywhere.

Also remove unused Wasm methods in MCContext.

Differential Revision: https://reviews.llvm.org/D37633

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@313058 91177308-0d34-0410-b5e6-96231b3b80d8
2017-09-12 18:31:24 +00:00
Peter Collingbourne
9283a09c18 IR: Replace the "Linker Options" module flag with "llvm.linker.options" named metadata.
The new metadata is easier to manipulate than module flags.

Differential Revision: https://reviews.llvm.org/D31349

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@305227 91177308-0d34-0410-b5e6-96231b3b80d8
2017-06-12 20:10:48 +00:00
Zachary Turner
19ca2b0f9d Move Object format code to lib/BinaryFormat.
This creates a new library called BinaryFormat that has all of
the headers from llvm/Support containing structure and layout
definitions for various types of binary formats like dwarf, coff,
elf, etc as well as the code for identifying a file from its
magic.

Differential Revision: https://reviews.llvm.org/D33843

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@304864 91177308-0d34-0410-b5e6-96231b3b80d8
2017-06-07 03:48:56 +00:00
Chandler Carruth
e3e43d9d57 Sort the remaining #include lines in include/... and lib/....
I did this a long time ago with a janky python script, but now
clang-format has built-in support for this. I fed clang-format every
line with a #include and let it re-sort things according to the precise
LLVM rules for include ordering baked into clang-format these days.

I've reverted a number of files where the results of sorting includes
isn't healthy. Either places where we have legacy code relying on
particular include ordering (where possible, I'll fix these separately)
or where we have particular formatting around #include lines that
I didn't want to disturb in this patch.

This patch is *entirely* mechanical. If you get merge conflicts or
anything, just ignore the changes in this patch and run clang-format
over your #include lines in the files.

Sorry for any noise here, but it is important to keep these things
stable. I was seeing an increasing number of patches with irrelevant
re-ordering of #include lines because clang-format was used. This patch
at least isolates that churn, makes it easy to skip when resolving
conflicts, and gets us to a clean baseline (again).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@304787 91177308-0d34-0410-b5e6-96231b3b80d8
2017-06-06 11:49:48 +00:00
Saleem Abdulrasool
5f20490446 CodeGen: add support for emitting ObjC image info
This ensures that we can emit the ObjC Image Info structure on COFF and
ELF as well.  The frontend already would attempt to emit this
information but would get dropped when generating assembly or an object
file.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@304736 91177308-0d34-0410-b5e6-96231b3b80d8
2017-06-05 21:26:39 +00:00
Javed Absar
13aa077a23 Add support for #pragma clang section
This patch provides a means to specify section-names for global variables,
functions and static variables, using #pragma directives.
This feature is only defined to work sensibly for ELF targets.
One can specify section names as:
#pragma clang section bss="myBSS" data="myData" rodata="myRodata" text="myText"
One can "unspecify" a section name with empty string e.g.
#pragma clang section bss="" data="" text="" rodata=""

Reviewers: Roger Ferrer, Jonathan Roelofs, Reid Kleckner
Differential Revision: https://reviews.llvm.org/D33413



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@304704 91177308-0d34-0410-b5e6-96231b3b80d8
2017-06-05 10:09:13 +00:00
Evgeniy Stepanov
fa138d2588 Ignore !associated metadata with null argument.
Fixes PR32577 (comment 10).
Such metadata may legitimately appear in LTO.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@302485 91177308-0d34-0410-b5e6-96231b3b80d8
2017-05-08 23:46:20 +00:00
Vedant Kumar
737d8b6809 [ProfileData] Unify getInstrProf*SectionName helpers
This is a version of D32090 that unifies all of the
`getInstrProf*SectionName` helper functions. (Note: the build failures
which D32090 would have addressed were fixed with r300352.)

We should unify these helper functions because they are hard to use in
their current form. E.g we recently introduced more helpers to fix
section naming for COFF files. This scheme doesn't totally succeed at
hiding low-level details about section naming, so we should switch to an
API that is easier to maintain.

This is not an NFC commit because it fixes llvm-cov's testing support
for COFF files (this falls out of the API change naturally). This is an
area where we lack tests -- I will see about adding one as a follow up.

Testing: check-clang, check-profile, check-llvm.

Differential Revision: https://reviews.llvm.org/D32097

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@300381 91177308-0d34-0410-b5e6-96231b3b80d8
2017-04-15 00:09:57 +00:00
Xinliang David Li
e8752f4f05 [Profile] Make host tool aware of object format when quering prof section names
Differential Revision: https://reviews.llvm.org/D32073


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@300352 91177308-0d34-0410-b5e6-96231b3b80d8
2017-04-14 17:48:40 +00:00
Xinliang David Li
2fc706bf3c [Profile] PE binary coverage bug fix
PR/32584

Differential Revision: https://reviews.llvm.org/D32023


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@300277 91177308-0d34-0410-b5e6-96231b3b80d8
2017-04-13 23:37:12 +00:00
Peter Collingbourne
8dc921e4a6 Move llvm::emitLinkerFlagsForGlobalCOFF() to Mangler.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@299183 91177308-0d34-0410-b5e6-96231b3b80d8
2017-03-31 04:46:50 +00:00
Evgeniy Stepanov
df808fe215 Add !associated metadata.
This is an ELF-specific thing that adds SHF_LINK_ORDER to the global's section
pointing to the metadata argument's section. The effect of that is a reverse dependency
between sections for the linker GC.

!associated does not change the behavior of global-dce. The global
may also need to be added to llvm.compiler.used.

Since SHF_LINK_ORDER is per-section, !associated effectively enables
fdata-sections for the affected globals, the same as comdats do.

Differential Revision: https://reviews.llvm.org/D29104

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@298157 91177308-0d34-0410-b5e6-96231b3b80d8
2017-03-17 22:17:24 +00:00
Eugene Zelenko
90d9920fc9 [CodeGen] Fix some Clang-tidy modernize and Include What You Use warnings; other minor fixes (NFC).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@296404 91177308-0d34-0410-b5e6-96231b3b80d8
2017-02-27 22:45:06 +00:00
Dan Gohman
53ff96ab08 [WebAssembly] Basic support for Wasm object file encoding.
With the "wasm32-unknown-unknown-wasm" triple, this allows writing out
simple wasm object files, and is another step in a larger series toward
migrating from ELF to general wasm object support. Note that this code
and the binary format itself is still experimental.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@296190 91177308-0d34-0410-b5e6-96231b3b80d8
2017-02-24 23:18:00 +00:00
Dan Gohman
d660a5d68c [WebAssembly] Add skeleton MC support for the Wasm container format
This just adds the basic skeleton for supporting a new object file format.
All of the actual encoding will be implemented in followup patches.

Differential Revision: https://reviews.llvm.org/D26722


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@295803 91177308-0d34-0410-b5e6-96231b3b80d8
2017-02-22 01:23:18 +00:00
Bob Haarman
ea59150166 [lto] add getLinkerOpts()
Summary: Some compilers, including MSVC and Clang, allow linker options to be specified in source files. In the legacy LTO API, there is a getLinkerOpts() method that returns linker options for the bitcode module being processed. This change adds that method to the new API, so that the COFF linker can get the right linker options when using the new LTO API.

Reviewers: pcc, ruiu, mehdi_amini, tejohnson

Reviewed By: pcc

Differential Revision: https://reviews.llvm.org/D29207



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@293950 91177308-0d34-0410-b5e6-96231b3b80d8
2017-02-02 23:00:49 +00:00
Reid Kleckner
ac0bab807c Revert "[COFF] Use 32-bit jump table entries in .rdata for Win64"
This reverts commit r290694. It broke sanitizer tests on Win64. I'll
probably bring this back, but the jump tables will just live in .text
like they do for MSVC.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@290714 91177308-0d34-0410-b5e6-96231b3b80d8
2016-12-29 17:07:10 +00:00
Reid Kleckner
0be69b14dc [COFF] Use 32-bit jump table entries in .rdata for Win64
Summary:
We were already using 32-bit jump table entries, but this was a
consequence of the default PIC model on Win64, and not an intentional
design decision. This patch ensures that we always use 32-bit label
difference jump table entries on Win64 regardless of the PIC model. This
is a good idea because it saves executable size and object file size.

Moving the jump tables to .rdata cleans up the disassembled object code
and reduces the available ROP targets, but it requires adding one more
RIP-relative lea to the code.  COFF doesn't have relocations to express
the difference between two arbitrary symbols, so we can't use the jump
table label in the label difference like we do elsewhere.

Fixes PR31488

Reviewers: majnemer, compnerd

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D28141

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@290694 91177308-0d34-0410-b5e6-96231b3b80d8
2016-12-29 00:12:39 +00:00
Prakhar Bahuguna
af672fb209 [ARM] Implement execute-only support in CodeGen
This implements execute-only support for ARM code generation, which
prevents the compiler from generating data accesses to code sections.
The following changes are involved:

* Add the CodeGen option "-arm-execute-only" to the ARM code generator.
* Add the clang flag "-mexecute-only" as well as the GCC-compatible
  alias "-mpure-code" to enable this option.
* When enabled, literal pools are replaced with MOVW/MOVT instructions,
  with VMOV used in addition for floating-point literals. As the MOVT
  instruction is required, execute-only support is only available in
  Thumb mode for targets supporting ARMv8-M baseline or Thumb2.
* Jump tables are placed in data sections when in execute-only mode.
* The execute-only text section is assigned section ID 0, and is
  marked as unreadable with the SHF_ARM_PURECODE flag with symbol 'y'.
  This also overrides selection of ELF sections for globals.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@289784 91177308-0d34-0410-b5e6-96231b3b80d8
2016-12-15 07:59:08 +00:00
Tim Northover
bc347f2914 CodeGen: simplify TargetMachine::getSymbol interface. NFC.
No-one actually had a mangler handy when calling this function, and
getSymbol itself went most of the way towards getting its own mangler
(with a local TLOF variable) so forcing all callers to supply one was
just extra complication.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@287645 91177308-0d34-0410-b5e6-96231b3b80d8
2016-11-22 16:17:20 +00:00