Support for DW_FORM_implicit_const DWARFv5 feature.
When this form is used attribute value goes to .debug_abbrev section (as SLEB).
As this form would break any debug tool which doesn't support DWARFv5
it is guarded by dwarf version check. Attempt to use this form with
dwarf version <= 4 is considered a fatal error.

Differential Revision: https://reviews.llvm.org/D28456


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@291599 91177308-0d34-0410-b5e6-96231b3b80d8

This reapplies rL289013 (reverted in rL289014) with the fixes identified
in D21731. Should hopefully pass the buildbots this time.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@290809 91177308-0d34-0410-b5e6-96231b3b80d8

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@289208 91177308-0d34-0410-b5e6-96231b3b80d8

Appears to break on build bots. Reverting pending investigation.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@289014 91177308-0d34-0410-b5e6-96231b3b80d8

The relocations for `DIEEntry::EmitValue` were wrong for Win64
(emitting FK_Data_4 instead of FK_SecRel_4). This corrects that
oversight so that the DWARF data is correct in Win64 COFF files.

Fixes PR15393.

Patch by Jameson Nash <jameson@juliacomputing.com> based on a patch
by David Majnemer.

Differential Revision: https://reviews.llvm.org/D21731

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@289013 91177308-0d34-0410-b5e6-96231b3b80d8

The only tests we have for the DWARF parser are the tests that use llvm-dwarfdump and expect output from textual dumps.

More DWARF parser modification are coming in the next few weeks and I wanted to add tests that can verify that we can encode and decode all form types, as well as test some other basic DWARF APIs where we ask DIE objects for their children and siblings.

DwarfGenerator.cpp was added in the lib/CodeGen directory. This file contains the code necessary to easily create DWARF for tests:

dwarfgen::Generator DG;
Triple Triple("x86_64--");
bool success = DG.init(Triple, Version);
if (!success)
  return;
dwarfgen::CompileUnit &CU = DG.addCompileUnit();
dwarfgen::DIE CUDie = CU.getUnitDIE();

CUDie.addAttribute(DW_AT_name, DW_FORM_strp, "/tmp/main.c");
CUDie.addAttribute(DW_AT_language, DW_FORM_data2, DW_LANG_C);

dwarfgen::DIE SubprogramDie = CUDie.addChild(DW_TAG_subprogram);
SubprogramDie.addAttribute(DW_AT_name, DW_FORM_strp, "main");
SubprogramDie.addAttribute(DW_AT_low_pc, DW_FORM_addr, 0x1000U);
SubprogramDie.addAttribute(DW_AT_high_pc, DW_FORM_addr, 0x2000U);

dwarfgen::DIE IntDie = CUDie.addChild(DW_TAG_base_type);
IntDie.addAttribute(DW_AT_name, DW_FORM_strp, "int");
IntDie.addAttribute(DW_AT_encoding, DW_FORM_data1, DW_ATE_signed);
IntDie.addAttribute(DW_AT_byte_size, DW_FORM_data1, 4);

dwarfgen::DIE ArgcDie = SubprogramDie.addChild(DW_TAG_formal_parameter);
ArgcDie.addAttribute(DW_AT_name, DW_FORM_strp, "argc");
// ArgcDie.addAttribute(DW_AT_type, DW_FORM_ref4, IntDie);
ArgcDie.addAttribute(DW_AT_type, DW_FORM_ref_addr, IntDie);

StringRef FileBytes = DG.generate();
MemoryBufferRef FileBuffer(FileBytes, "dwarf");
auto Obj = object::ObjectFile::createObjectFile(FileBuffer);
EXPECT_TRUE((bool)Obj);
DWARFContextInMemory DwarfContext(*Obj.get());
This code is backed by the AsmPrinter code that emits DWARF for the actual compiler.

While adding unit tests it was discovered that DIEValue that used DIEEntry as their values had bugs where DW_FORM_ref1, DW_FORM_ref2, DW_FORM_ref8, and DW_FORM_ref_udata forms were not supported. These are all now supported. Added support for DW_FORM_string so we can emit inlined C strings.

Centralized the code to unique abbreviations into a new DIEAbbrevSet class and made both the dwarfgen::Generator and the llvm::DwarfFile classes use the new class.

Fixed comments in the llvm::DIE class so that the Offset is known to be the compile/type unit offset.

DIEInteger now supports more DW_FORM values.

There are also unit tests that cover:

Encoding and decoding all form types and values
Encoding and decoding all reference types (DW_FORM_ref1, DW_FORM_ref2, DW_FORM_ref4, DW_FORM_ref8, DW_FORM_ref_udata, DW_FORM_ref_addr) including cross compile unit references with that go forward one compile unit and backward on compile unit.

Differential Revision: https://reviews.llvm.org/D27326


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@289010 91177308-0d34-0410-b5e6-96231b3b80d8

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@288421 91177308-0d34-0410-b5e6-96231b3b80d8

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@288401 91177308-0d34-0410-b5e6-96231b3b80d8

This change removes the dependency on DwarfDebug that was used for DW_FORM_ref_addr by making a new DIEUnit class in DIE.cpp.

The DIEUnit class represents a compile or type unit and it owns the unit DIE as an instance variable. This allows anyone with a DIE, to get the unit DIE, and then get back to its DIEUnit without adding any new ivars to the DIE class. Why was this needed? The DIE class has an Offset that is always the CU relative DIE offset, not the "offset in debug info section" as was commented in the header file (the comment has been corrected). This is great for performance because most DIE references are compile unit relative and this means most code that accessed the DIE's offset didn't need to make it into a compile unit relative offset because it already was. When we needed to emit a DW_FORM_ref_addr though, we needed to find the absolute offset of the DIE by finding the DIE's compile/type unit. This class did have the absolute debug info/type offset and could be added to the CU relative offset to compute the absolute offset. With this change we can easily get back to a DIE's DIEUnit which will have this needed offset. Prior to this is required having a DwarfDebug and required calling:

DwarfCompileUnit *DwarfDebug::lookupUnit(const DIE *CU) const;
Now we can use the DIEUnit class to do so without needing DwarfDebug. All clients now use DIEUnit objects (the DwarfDebug stack and the DwarfLinker). A follow on patch for the DWARF generator will also take advantage of this.

Differential Revision: https://reviews.llvm.org/D27170



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@288399 91177308-0d34-0410-b5e6-96231b3b80d8

This patch makes AsmPrinter less reliant on DwarfDebug by relying on the DWARF version in the AsmPrinter's MCStreamer's MCContext. This allows us to remove the redundant DWARF version from DwarfDebug. It also lets us change code that used to access the AsmPrinter's DwarfDebug just to get to the DWARF version by changing the DWARF version accessor on AsmPrinter so that it grabs the version from its MCStreamer's MCContext.

Differential Revision: https://reviews.llvm.org/D27032


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@287839 91177308-0d34-0410-b5e6-96231b3b80d8

This reverts commit r283285 and re-commit r283275 with
a fix for format("%s", Str); where Str is a StringRef.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@283298 91177308-0d34-0410-b5e6-96231b3b80d8

One test seems randomly broken: DebugInfo/X86/gnu-public-names.ll

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@283285 91177308-0d34-0410-b5e6-96231b3b80d8

This reverts commit r283278 and re-commit r283275 with
the update to fix the build on the LLDB side.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@283281 91177308-0d34-0410-b5e6-96231b3b80d8

This reverts commit r283275, it broke LLDB Android debug server.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@283278 91177308-0d34-0410-b5e6-96231b3b80d8

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@283275 91177308-0d34-0410-b5e6-96231b3b80d8

Follow up to r278902. I had missed "fall through", with a space.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@278970 91177308-0d34-0410-b5e6-96231b3b80d8

Rather than storing type units in a vector and emitting them at the end
of code generation, emit them immediately and destroy them, reclaiming the
memory we were using for their DIEs.

In one benchmark carried out against Chromium's 50 largest (by bitcode
file size) translation units, total peak memory consumption with type units
decreased by median 17%, or by 7% when compared against disabling type units.

Tested using check-{llvm,clang}, the GDB 7.5 test suite (with
'-fdebug-types-section') and by eyeballing llvm-dwarfdump output on those
Chromium translation units with split DWARF both disabled and enabled, and
verifying that the only changes were to addresses and abbreviation ordering.

Differential Revision: http://reviews.llvm.org/D17118

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@260578 91177308-0d34-0410-b5e6-96231b3b80d8

Changed emitting offset of macinfo entry into compiler unit DIE to use "addSectionLabel" method rather than explicitly calculating size/offset of macro entry.

Differential Revision: http://reviews.llvm.org/D16292


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@259358 91177308-0d34-0410-b5e6-96231b3b80d8

Differential Revision: http://reviews.llvm.org/D15495

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@257060 91177308-0d34-0410-b5e6-96231b3b80d8

Switch dump()/print() method definitions to LLVM_DUMP_METHOD instead.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253945 91177308-0d34-0410-b5e6-96231b3b80d8

Split out a helper `printValues()` for printing `DIEBlock` and `DIELoc`,
instead of relying on `DIE::print()`.  The shared code was actually
fairly small there.  No functionality change intended.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243856 91177308-0d34-0410-b5e6-96231b3b80d8

Rewrite `DIEValueList` as a subclass of `DIE`, renaming its API to match
`DIE`'s.  This is preparation for changing `DIEBlock` and `DIELoc` to
stop inheriting from `DIE` and inherit directly from `DIEValueList`.

I thought about leaving this as a has-a relationship (and changing
`DIELoc` and `DIEBlock` to also have-a `DIEValueList`), but that seemed
to require a fair bit more boilerplate and I think it needed more
changes to the `DwarfUnit` API than this will.

No functionality change intended here.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243854 91177308-0d34-0410-b5e6-96231b3b80d8

Summary:
Because llvm-dsymutil is using ASMPrinter without any MachineFunction
of Module available.

This change is part of a series of commits dedicated to have a single
DataLayout during compilation by using always the one owned by the
module.

Reviewers: echristo

Subscribers: yaron.keren, rafael, llvm-commits

Differential Revision: http://reviews.llvm.org/D11078

From: Mehdi Amini <mehdi.amini@apple.com>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@242384 91177308-0d34-0410-b5e6-96231b3b80d8

Replace the `std::vector<>` for `DIE::Children` with an intrusively
linked list.  This is a strict memory improvement: it requires no
auxiliary storage, and reduces `sizeof(DIE)` by one pointer.  It also
factors out the DIE-related malloc traffic.

This drops llc memory usage from 735 MB down to 718 MB, or ~2.3%.

(I'm looking at `llc` memory usage on `verify-uselistorder.lto.opt.bc`;
see r236629 for details.)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240736 91177308-0d34-0410-b5e6-96231b3b80d8

Change `DIE::Values` to a singly linked list, where each node is
allocated on a `BumpPtrAllocator`.  In order to support `push_back()`,
the list is circular, and points at the tail element instead of the
head.  I abstracted the core list logic out to `IntrusiveBackList` so
that it can be reused for `DIE::Children`, which also cares about
`push_back()`.

This drops llc memory usage from 799 MB down to 735 MB, about 8%.

(I'm looking at `llc` memory usage on `verify-uselistorder.lto.opt.bc`;
see r236629 for details.)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240733 91177308-0d34-0410-b5e6-96231b3b80d8

Stop taking a `dwarf::Form` in `DIEValue::EmitValue()` and
`DIEValue::SizeOf()`, since they're always passed `DIEValue::getForm()`
anyway.  This is just left over from when `DIEValue` didn't know its own
form.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240566 91177308-0d34-0410-b5e6-96231b3b80d8

Different object formats represent references from dwarf in different ways.

ELF uses a relocation to the referenced point (except for .dwo) and
COFF/MachO use the offset of the referenced point inside its section.

This patch renames emitSectionOffset because

* It doesn't produce an offset on ELF.
* It changes behavior depending on how DWARF is represented, so adding
dwarf to its name is probably a good thing.

The patch also adds an option to force the use of offsets.That avoids
funny looking code like

  if (!UseOffsets)
    Asm->emitSectionOffset....

It was correct, but read as if the ! was inverted.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239866 91177308-0d34-0410-b5e6-96231b3b80d8

Change the `DIE` API to hide the implementation of the list of
`DIEValue`s.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238369 91177308-0d34-0410-b5e6-96231b3b80d8

Stop storing a `DIEAbbrev` in `DIE`, since the data fits neatly inside
the `DIEValue` list.  Besides being a cleaner data structure (avoiding
the parallel arrays), this gives us more freedom to rearrange the
`DIEValue` list.

This fixes the temporary memory regression from 845 MB up to 879 MB, and
drops it further to 829 MB for a net memory decrease of around 1.9%
(incremental decrease around 5.7%).

(I'm looking at `llc` memory usage on `verify-uselistorder.lto.opt.bc`;
see r236629 for details.)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238364 91177308-0d34-0410-b5e6-96231b3b80d8

This reverts commit r238350, effectively reapplying r238349 after fixing
(all?) the problems, all somehow related to how I was using
`AlignedArrayCharUnion<>` inside `DIEValue`:

  - MSVC can only handle `sizeof()` on types, not values.  Change the
    assert.
  - GCC doesn't know the `is_trivially_copyable` type trait.  Instead of
    asserting it, add destructors.
  - Call placement new even when constructing POD (i.e., the pointers).
  - Instead of copying the char buffer, copy the casted classes.

I've left in a couple of `static_assert`s that I think both MSVC and GCC
know how to handle.  If the bots disagree with me, I'll remove them.

  - Check that the constructed type is either standard layout or a
    pointer.  This protects against a programming error: we really want
    the "small" `DIEValue`s to be small and simple, so don't
    accidentally change them not to be.
  - Similarly, check that the size of the buffer is no bigger than a
    `uint64_t` or a pointer.  (I thought checking against
    `sizeof(uint64_t)` would be good enough, but Chandler suggested that
    pointers might sometimes be bigger than that in the context of
    sanitizers.)

I've also committed r238359 in the meantime, which introduces a
DIEValue.def to simplify dispatching between the various types (thanks
to a review comment by David Blaikie).  Without that, this commit would
be almost unintelligible.

Here's the original commit message:
--
Change `DIEValue` to be stored/passed/etc. by value, instead of
reference.  It's now a discriminated union, with a `Val` field storing
the actual type.  The classes that used to inherit from `DIEValue` no
longer do.  There are two categories of these:

  - Small values fit in a single pointer and are stored by value.
  - Large values require auxiliary storage, and are stored by reference.

The only non-mechanical change is to tools/dsymutil/DwarfLinker.cpp.  It
was relying on `DIEInteger`s being passed around by reference, so I
replaced that assumption with a `PatchLocation` type that stores a safe
reference to where the `DIEInteger` lives instead.

This commit causes a temporary regression in memory usage, since I've
left merging `DIEAbbrevData` into `DIEValue` for a follow-up commit.  I
measured an increase from 845 MB to 879 MB, around 3.9%.  The follow-up
drops it lower than the starting point, and I've only recently brought
the memory this low anyway, so I'm committing these changes separately
to keep them incremental.  (I also considered swapping the commits, but
the other one first would cause a lot more code churn.)

(I'm looking at `llc` memory usage on `verify-uselistorder.lto.opt.bc`;
see r236629 for details.)
--

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238362 91177308-0d34-0410-b5e6-96231b3b80d8

Use a .def macro file to iterate through the various subclasses of
`DIEValue`.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238359 91177308-0d34-0410-b5e6-96231b3b80d8

This reverts commit r238349, since it caused some errors on bots:
  - std::is_trivially_copyable isn't available until GCC 5.0.
  - It was complaining about strict aliasing with my use of
    ArrayCharUnion.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238350 91177308-0d34-0410-b5e6-96231b3b80d8

Change `DIEValue` to be stored/passed/etc. by value, instead of
reference.  It's now a discriminated union, with a `Val` field storing
the actual type.  The classes that used to inherit from `DIEValue` no
longer do.  There are two categories of these:

  - Small values fit in a single pointer and are stored by value.
  - Large values require auxiliary storage, and are stored by reference.

The only non-mechanical change is to tools/dsymutil/DwarfLinker.cpp.  It
was relying on `DIEInteger`s being passed around by reference, so I
replaced that assumption with a `PatchLocation` type that stores a safe
reference to where the `DIEInteger` lives instead.

This commit causes a temporary regression in memory usage, since I've
left merging `DIEAbbrevData` into `DIEValue` for a follow-up commit.  I
measured an increase from 845 MB to 879 MB, around 3.9%.  The follow-up
drops it lower than the starting point, and I've only recently brought
the memory this low anyway, so I'm committing these changes separately
to keep them incremental.  (I also considered swapping the commits, but
the other one first would cause a lot more code churn.)

(I'm looking at `llc` memory usage on `verify-uselistorder.lto.opt.bc`;
see r236629 for details.)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238349 91177308-0d34-0410-b5e6-96231b3b80d8

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238315 91177308-0d34-0410-b5e6-96231b3b80d8

Expose the `DwarfStringPool` entry in a header, and store a pointer to
it directly in `DIEString`.  Instead of choosing at creation time how to
emit it, use the `dwarf::Form` to determine that at emission time.
Besides avoiding the other `DIEValue`, this shaves two pointers off of
`DIEString`; the data is now a single pointer.  This is a nice cleanup
on its own -- and drops memory usage from 861 MB down to 853 MB, around
0.9% -- but it's also preparation for passing `DIEValue`s by value.

(I'm looking at `llc` memory usage on `verify-uselistorder.lto.opt.bc`;
see r236629 for details.)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238117 91177308-0d34-0410-b5e6-96231b3b80d8

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238099 91177308-0d34-0410-b5e6-96231b3b80d8

Remove all virtual functions from `DIEValue`, dropping the vtable
pointer from its layout.  Instead, create "impl" functions on the
subclasses, and use the `DIEValue::Type` to implement the dynamic
dispatch.

This is necessary -- obviously not sufficient -- for passing `DIEValue`s
around by value.  However, this change stands on its own: we make tons
of these.  I measured a drop in memory usage from 888 MB down to 860 MB,
or around 3.2%.

(I'm looking at `llc` memory usage on `verify-uselistorder.lto.opt.bc`;
see r236629 for details.)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238084 91177308-0d34-0410-b5e6-96231b3b80d8

We already have this in `DIEValue`; no reason to shadow it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238082 91177308-0d34-0410-b5e6-96231b3b80d8

AsmPrinter owns the OutStreamer, so an owning pointer makes sense here. Using a
reference for this is crufty.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@235752 91177308-0d34-0410-b5e6-96231b3b80d8

This commit removes `DebugLocList` and replaces it with
`DebugLocStream`.

  - `DebugLocEntry` no longer contains its byte/comment streams.
  - The `DebugLocEntry` list for a variable/inlined-at pair is allocated
    on the stack, and released right after `DebugLocEntry::finalize()`
    (possible because of the refactoring in r231023).  Now, only one
    list is in memory at a time now.
  - There's a single unified stream for the `.debug_loc` section that
    persists, stored in the new `DebugLocStream` data structure.

The last point is important: this collapses the nested `SmallVector<>`s
from `DebugLocList` into unified streams.  We previously had something
like the following:

    vec<tuple<Label, CU,
              vec<tuple<BeginSym, EndSym,
                        vec<Value>,
                        vec<char>,
                        vec<string>>>>>

A `SmallVector` can avoid allocations, but is statically fairly large
for a vector: three pointers plus the size of the small storage, which
is the number of elements in small mode times the element size).
Nesting these is expensive, since an inner vector's size contributes to
the element size of an outer one.  (Nesting any vector is expensive...)

In the old data structure, the outer vector's *element* size was 632B,
excluding allocation costs for when the middle and inner vectors
exceeded their small sizes.  312B of this was for the "three" pointers
in the vector-tree beneath it.  If you assume 1M functions with an
average of 10 variable/inlined-at pairs each (in an LTO scenario),
that's almost 6GB (besides inner allocations), with almost 3GB for the
"three" pointers.

This came up in a heap profile a little while ago of a `clang -flto -g`
bootstrap, with `DwarfDebug::collectVariableInfo()` using something like
10-15% of the total memory.

With this commit, we have:

    tuple<vec<tuple<Label, CU, Offset>>,
          vec<tuple<BeginSym, EndSym, Offset, Offset>>,
          vec<char>,
          vec<string>>

The offsets are used to create `ArrayRef` slices of adjacent
`SmallVector`s.  This reduces the number of vectors to four (unrelated
to the number of variable/inlined-at pairs), and caps the number of
allocations at the same number.

Besides saving memory and limiting allocations, this is NFC.

I don't know my way around this code very well yet, but I wonder if we
could go further: why stream to a side-table, instead of directly to the
output stream?

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@235229 91177308-0d34-0410-b5e6-96231b3b80d8