[MC] De-capitalize SwitchSection. NFC

Add SwitchSection to return switchSection. The API will be removed soon.

Cleanup includes: DebugInfo & CodeGen

Discourse thread: https://discourse.llvm.org/t/include-what-you-use-include-cleanup
Differential Revision: https://reviews.llvm.org/D121332

[CodeGen][Debuginfo][NFC] Refactor DIE values SizeOf method to not depend on AsmPrinter.

SizeOf() method of DIE values(unsigned SizeOf(const AsmPrinter *AP, dwarf::Form Form) const)
depends on AsmPr

[CodeGen][Debuginfo][NFC] Refactor DIE values SizeOf method to not depend on AsmPrinter.

SizeOf() method of DIE values(unsigned SizeOf(const AsmPrinter *AP, dwarf::Form Form) const)
depends on AsmPrinter. AsmPrinter is too specific class here. This patch removes dependency
on AsmPrinter and use dwarf::FormParams structure instead. It allows calculate DIE values
size without using AsmPrinter. That refactoring is useful for D96035([dsymutil][DWARFlinker]
implement separate multi-thread processing for compile units.)

Differential Revision: https://reviews.llvm.org/D116997

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DwarfFile.h - remove unnecessary includes. NFCI.

Use forward declarations where possible, move includes down to DwarfFile.cpp and avoid duplicate includes.

[DebugInfo] Make offsets of dwarf units 64-bit (19/19).

In the case of LTO, several DWARF units can be emitted in one section.
For an extremely large application, they may exceed the limit of 4GiB
f

[DebugInfo] Make offsets of dwarf units 64-bit (19/19).

In the case of LTO, several DWARF units can be emitted in one section.
For an extremely large application, they may exceed the limit of 4GiB
for 32-bit offsets. As it is now possible to emit 64-bit debugging info,
the patch enables storing the larger offsets.

Differential Revision: https://reviews.llvm.org/D87026

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[DebugInfo] Fix emitting DWARF64 compilation units (5/19).

The patch also adds a method to choose an appropriate DWARF form
to represent section offsets according to the version and the format
of pr

[DebugInfo] Fix emitting DWARF64 compilation units (5/19).

The patch also adds a method to choose an appropriate DWARF form
to represent section offsets according to the version and the format
of producing debug info.

Differential Revision: https://reviews.llvm.org/D87014

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[MC] De-capitalize another set of MCStreamer::Emit* functions

Emit{ValueTo,Code}Alignment Emit{DTP,TP,GP}* EmitSymbolValue etc

Reapply "NFC: DebugInfo: Refactor RangeSpanList to be a struct, like DebugLocStream::List"

Move these data structures closer together so their emission code can
eventually share more of its implemen

Reapply "NFC: DebugInfo: Refactor RangeSpanList to be a struct, like DebugLocStream::List"

Move these data structures closer together so their emission code can
eventually share more of its implementation.

Was an egregious bug (completely untested, evidently) where I hadn't
inverted a DWARFv5 test as needed, so it was doing the exact opposite of
what was required & thus tried to emit a DWARFv5 range list header in
DWARFv4.

Reapply 8e04896288d22ed8bef7ac367923374f96b753d6 which was
reverted in a8154e5e0c83d2f0f65f3b4fb1a0bc68785bd975.

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Temporarily revert "NFC: DebugInfo: Refactor RangeSpanList to be a struct, like DebugLocStream::List"
as it was causing bot and build failures.

This reverts commit 8e04896288d22ed8bef7ac367923374f96

Temporarily revert "NFC: DebugInfo: Refactor RangeSpanList to be a struct, like DebugLocStream::List"
as it was causing bot and build failures.

This reverts commit 8e04896288d22ed8bef7ac367923374f96b753d6.

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NFC: DebugInfo: Refactor RangeSpanList to be a struct, like DebugLocStream::List

Move these data structures closer together so their emission code can
eventually share more of its implementation.

DebugInfo: Split DWARF + gmlt + no-split-dwarf-inlining shouldn't emit anything to the .dwo file

This configuration (due to r349207) was intended not to emit any DWO CU,
but a degenerate CU was stil

DebugInfo: Split DWARF + gmlt + no-split-dwarf-inlining shouldn't emit anything to the .dwo file

This configuration (due to r349207) was intended not to emit any DWO CU,
but a degenerate CU was still being emitted - containing a header and a
DW_TAG_compile_unit with no attributes.

Under that situation, emit nothing to the .dwo file. (since this is a
dynamic property of the input the .dwo file is still emitted, just with
nothing in it (so a valid, but empty, ELF file) - if some other CU
didn't satisfy this criteria, its DWO CU would still go there, etc)

llvm-svn: 353771

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Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the ne

Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636

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Recommit r348806: DebugInfo: Use symbol difference for CU length to simplify assembly reading/editing

Mucking about simplifying a test case ( https://reviews.llvm.org/D55261 ) I stumbled across some

Recommit r348806: DebugInfo: Use symbol difference for CU length to simplify assembly reading/editing

Mucking about simplifying a test case ( https://reviews.llvm.org/D55261 ) I stumbled across something I've hit before - that LLVM's (GCC's does too, FWIW) assembly output includes a hardcode length for a DWARF unit in its header. Instead we could emit a label difference - making the assembly easier to read/edit (though potentially at a slight (I haven't tried to observe it) performance cost of delaying/sinking the length computation into the MC layer).

Fix: Predicated all the changes (including creating the labels, even if they aren't used/needed) behind the NVPTX useSectionsAsReferences, avoiding emitting labels in NVPTX where ptxas can't parse them.

Reviewers: JDevlieghere, probinson, ABataev

Differential Revision: https://reviews.llvm.org/D55281

llvm-svn: 349430

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DebugInfo: Avoid using split DWARF when the split unit would be empty.

In ThinLTO many split CUs may be effectively empty because of the lack
of support for cross-unit references in split DWARF.

Us

DebugInfo: Avoid using split DWARF when the split unit would be empty.

In ThinLTO many split CUs may be effectively empty because of the lack
of support for cross-unit references in split DWARF.

Using a split unit in those cases is just a waste/overhead - and turned
out to be one contributor to a significant symbolizer performance issue
when global variable debug info was being imported (see r348416 for the
primary fix) due to symbolizers seeing CUs with no ranges, assuming
there might still be addresses covered and walking into the split CU to
see if there are any ranges (when that split CU was in a DWP file, that
meant loading the DWP and its index, the index was extra large because
of all these fractured/empty CUs... and so was very expensive to load).

(the 3rd fix which will follow, is to assume that a CU with no ranges is
empty rather than merely missing its CU level range data - and to not
walk into its DIEs (split or otherwise) in search of address information
that is generally not present)

llvm-svn: 349207

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Revert "debuginfo: Use symbol difference for CU length to simplify assembly reading/editing"

Temporarily reverts commit r348806 due to strange asm compilation issues in certain modes (combination of

Revert "debuginfo: Use symbol difference for CU length to simplify assembly reading/editing"

Temporarily reverts commit r348806 due to strange asm compilation issues in certain modes (combination of asan+cuda+other things). Will provide repro soon.

llvm-svn: 348898

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debuginfo: Use symbol difference for CU length to simplify assembly reading/editing

Mucking about simplifying a test case ( https://reviews.llvm.org/D55261 ) I stumbled across something I've hit bef

debuginfo: Use symbol difference for CU length to simplify assembly reading/editing

Mucking about simplifying a test case ( https://reviews.llvm.org/D55261 ) I stumbled across something I've hit before - that LLVM's (GCC's does too, FWIW) assembly output includes a hardcode length for a DWARF unit in its header. Instead we could emit a label difference - making the assembly easier to read/edit (though potentially at a slight (I haven't tried to observe it) performance cost of delaying/sinking the length computation into the MC layer).

Reviewers: JDevlieghere, probinson, ABataev

Differential Revision: https://reviews.llvm.org/D55281

llvm-svn: 348806

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NFC: DebugInfo: Track the origin CU rather than just the base address for range lists

Turns out knowing more than just the base address might be useful -
specifically a future change to respect a DI

NFC: DebugInfo: Track the origin CU rather than just the base address for range lists

Turns out knowing more than just the base address might be useful -
specifically a future change to respect a DICompileUnit flag for the use
of base address specifiers in DWARF < 5.

llvm-svn: 346380

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DebugInfo: Use address pool forms in debug_rnglists

Save no relocations by reusing addresses from the address pool.

llvm-svn: 344836

Revert BTF commit series.

The initial patch was not reviewed, and does not have any tests;
it should not have been merged.

This reverts 344395, 344390, 344387, 344385, 344381, 344376,
and 344366.

Revert BTF commit series.

The initial patch was not reviewed, and does not have any tests;
it should not have been merged.

This reverts 344395, 344390, 344387, 344385, 344381, 344376,
and 344366.

llvm-svn: 344405

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[BPF] Add BTF generation for BPF target

BTF is the debug format for BPF, a kernel virtual machine
and widely used for tracing, networking and security, etc ([1]).

Currently only instruction streams

[BPF] Add BTF generation for BPF target

BTF is the debug format for BPF, a kernel virtual machine
and widely used for tracing, networking and security, etc ([1]).

Currently only instruction streams are passed to kernel,
the kernel verifier verifies them before execution. In order to
provide better visibility of bpf programs to user space
tools, some debug information, e.g., function names and
debug line information are desirable for kernel so tools
can get such information with better annotation
for jited instructions for performance or other reasons.

The dwarf is too complicated in kernel and for BPF.
Hence, BTF is designed to be the debug format for BPF ([2]).
Right now, pahole supports BTF for types, which
are generated based on dwarf sections in the ELF file.

In order to annotate performance metrics for jited bpf insns,
it is necessary to pass debug line info to the kernel.
Furthermore, we want to pass the actual code to the
kernel because of the following reasons:

. bpf program typically is small so storage overhead
should be small.
. in bpf land, it is totally possible that
an application loads the bpf program into the
kernel and then that application quits, so
holding debug info by the user space application
is not practical.
. having source codes directly kept by kernel
would ease deployment since the original source
code does not need ship on every hosts and
kernel-devel package does not need to be
deployed even if kernel headers are used.

The only reliable time to get the source code is
during compilation time. This will result in both more
accurate information and easier deployment as
stated in the above.

Another consideration is for JIT. The project like bcc
use MCJIT to compile a C program into bpf insns and
load them to the kernel ([3]). The generated BTF sections
will be readily available for such cases as well.

This patch implemented generation of BTF info in llvm
compiler. The BTF related sections will be generated
when both -target bpf and -g are specified. Two sections
are generated:
.BTF contains all the type and string information, and
.BTF.ext contains the func_info and line_info.

The separation is related to how two sections are used
differently in bpf loader, e.g., linux libbpf ([4]).
The .BTF section can be loaded into the kernel directly
while .BTF.ext needs loader manipulation before loading
to the kernel. The format of the each section is roughly
defined in llvm:include/llvm/MC/MCBTFContext.h and
from the implementation in llvm:lib/MC/MCBTFContext.cpp.
A later example also shows the contents in each section.

The type and func_info are gathered during CodeGen/AsmPrinter
by traversing dwarf debug_info. The line_info is
gathered in MCObjectStreamer before writing to
the object file. After all the information is gathered,
the two sections are emitted in MCObjectStreamer::finishImpl.

With cmake CMAKE_BUILD_TYPE=Debug, the compiler can
dump out all the tables except insn offset, which
will be resolved later as relocation records.
The debug type "btf" is used for BTFContext dump.

Dwarf tests the debug info generation with
llvm-dwarfdump to decode the binary sections and
check whether the result is expected. Currently
we do not have such a tool yet. We will implement
btf dump functionality in bpftool ([5]) as the bpftool is
considered the recommended tool for bpf introspection.
The implementation for type and func_info is tested
with linux kernel test cases. The line_info is visually
checked with dump from linux kernel libbpf ([4]) and
checked with readelf dumping section raw data.

Note that the .BTF and .BTF.ext information will not
be emitted to assembly code and there is no assembler
support for BTF either.

In the below, with a clang/llvm built with CMAKE_BUILD_TYPE=Debug,
Each table contents are shown for a simple C program.

-bash-4.2$ cat -n test.c
1 struct A {
2 int a;
3 char b;
4 };
5
6 int test(struct A *t) {
7 return t->a;
8 }
-bash-4.2$ clang -O2 -target bpf -g -mllvm -debug-only=btf -c test.c
Type Table:
[1] FUNC name_off=1 info=0x0c000001 size/type=2
param_type=3
[2] INT name_off=12 info=0x01000000 size/type=4
desc=0x01000020
[3] PTR name_off=0 info=0x02000000 size/type=4
[4] STRUCT name_off=16 info=0x04000002 size/type=8
name_off=18 type=2 bit_offset=0
name_off=20 type=5 bit_offset=32
[5] INT name_off=22 info=0x01000000 size/type=1
desc=0x02000008

String Table:
0 :
1 : test
6 : .text
12 : int
16 : A
18 : a
20 : b
22 : char
27 : test.c
34 : int test(struct A *t) {
58 : return t->a;

FuncInfo Table:
sec_name_off=6
insn_offset=<Omitted> type_id=1

LineInfo Table:
sec_name_off=6
insn_offset=<Omitted> file_name_off=27 line_off=34 line_num=6 column_num=0
insn_offset=<Omitted> file_name_off=27 line_off=58 line_num=7 column_num=3
-bash-4.2$ readelf -S test.o
......
[12] .BTF PROGBITS 0000000000000000 0000028d
00000000000000c1 0000000000000000 0 0 1
[13] .BTF.ext PROGBITS 0000000000000000 0000034e
0000000000000050 0000000000000000 0 0 1
[14] .rel.BTF.ext REL 0000000000000000 00000648
0000000000000030 0000000000000010 16 13 8
......
-bash-4.2$

The latest linux kernel ([6]) can already support .BTF with type information.
The [7] has the reference implementation in linux kernel side
to support .BTF.ext func_info. The .BTF.ext line_info support is not
implemented yet. If you have difficulty accessing [6], you can
manually do the following to access the code:

git clone https://github.com/yonghong-song/bpf-next-linux.git
cd bpf-next-linux
git checkout btf

The change will push to linux kernel soon once this patch is landed.

References:
[1]. https://www.kernel.org/doc/Documentation/networking/filter.txt
[2]. https://lwn.net/Articles/750695/
[3]. https://github.com/iovisor/bcc
[4]. https://github.com/torvalds/linux/tree/master/tools/lib/bpf
[5]. https://github.com/torvalds/linux/tree/master/tools/bpf/bpftool
[6]. https://github.com/torvalds/linux
[7]. https://github.com/yonghong-song/bpf-next-linux/tree/btf

Signed-off-by: Song Liu <[email protected]>
Signed-off-by: Yonghong Song <[email protected]>
Acked-by: Alexei Starovoitov <[email protected]>

Differential Revision: https://reviews.llvm.org/D52950

llvm-svn: 344366

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[DebugInfo] Generate DWARF debug information for labels. (Fix leak problems)

There are two forms for label debug information in DWARF format.

1. Labels in a non-inlined function:

DW_TAG_label
DW

[DebugInfo] Generate DWARF debug information for labels. (Fix leak problems)

There are two forms for label debug information in DWARF format.

1. Labels in a non-inlined function:

DW_TAG_label
DW_AT_name
DW_AT_decl_file
DW_AT_decl_line
DW_AT_low_pc

2. Labels in an inlined function:

DW_TAG_label
DW_AT_abstract_origin
DW_AT_low_pc

We will collect label information from DBG_LABEL. Before every DBG_LABEL,
we will generate a temporary symbol to denote the location of the label.
The symbol could be used to get DW_AT_low_pc afterwards. So, we create a
mapping between 'inlined label' and DBG_LABEL MachineInstr in DebugHandlerBase.
The DBG_LABEL in the mapping is used to query the symbol before it.

The AbstractLabels in DwarfCompileUnit is used to process labels in inlined
functions.

We also keep a mapping between scope and labels in DwarfFile to help to
generate correct tree structure of DIEs.

It also generates label debug information under global isel.

Differential Revision: https://reviews.llvm.org/D45556

llvm-svn: 340039

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Revert "[DebugInfo] Generate DWARF debug information for labels. (Fix leak problems)"

This reverts commit cb8c5e417d55141f3f079a8a876e786f44308336 / r339676.

This causing a test to fail in http://g

Revert "[DebugInfo] Generate DWARF debug information for labels. (Fix leak problems)"

This reverts commit cb8c5e417d55141f3f079a8a876e786f44308336 / r339676.

This causing a test to fail in http://green.lab.llvm.org/green/job/clang-stage1-configure-RA/48406/

LLVM :: DebugInfo/Generic/debug-label.ll

llvm-svn: 339700

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[DebugInfo] Generate DWARF debug information for labels. (Fix leak problems)

There are two forms for label debug information in DWARF format.

1. Labels in a non-inlined function:

DW_TAG_label
DW

[DebugInfo] Generate DWARF debug information for labels. (Fix leak problems)

There are two forms for label debug information in DWARF format.

1. Labels in a non-inlined function:

DW_TAG_label
DW_AT_name
DW_AT_decl_file
DW_AT_decl_line
DW_AT_low_pc

2. Labels in an inlined function:

DW_TAG_label
DW_AT_abstract_origin
DW_AT_low_pc

We will collect label information from DBG_LABEL. Before every DBG_LABEL,
we will generate a temporary symbol to denote the location of the label.
The symbol could be used to get DW_AT_low_pc afterwards. So, we create a
mapping between 'inlined label' and DBG_LABEL MachineInstr in DebugHandlerBase.
The DBG_LABEL in the mapping is used to query the symbol before it.

The AbstractLabels in DwarfCompileUnit is used to process labels in inlined
functions.

We also keep a mapping between scope and labels in DwarfFile to help to
generate correct tree structure of DIEs.

It also generates label debug information under global isel.

Differential Revision: https://reviews.llvm.org/D45556

llvm-svn: 339676

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[DEBUGINFO] Disable emission of the dwarf sections, but allow directives.

Summary:
Added an option that allows to emit only '.loc' and '.file' kind debug
directives, but disables emission of the DWA

[DEBUGINFO] Disable emission of the dwarf sections, but allow directives.

Summary:
Added an option that allows to emit only '.loc' and '.file' kind debug
directives, but disables emission of the DWARF sections. Required for
NVPTX target to support profiling. It requires '.loc' and '.file'
directives, but does not require any DWARF sections for the profiler.

Reviewers: probinson, echristo, dblaikie

Subscribers: aprantl, JDevlieghere, llvm-commits

Differential Revision: https://reviews.llvm.org/D46021

llvm-svn: 338616

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Revert "[DebugInfo] Generate DWARF debug information for labels."

This reverts commits r338390 and r338398, they were causing LSan
failures on the ASan bot.

llvm-svn: 338408