Another attempt to land the changes in debug line header to prevent duplicate
files in Dwarf 5. I rolled back my previous commit because of a mistake in
generating the object file in a test. Meanwhile, I addressed some offline
comments and changed the implementation; the largest difference is that
MCDwarfLineTableHeader does not keep DwarfVersion but gets it as a parameter. I
also merged the patch to fix two lld tests that will strt to fail into this
patch.
Original Commit:
https://reviews.llvm.org/D59515
Original Message:
Motivation: In previous dwarf versions, file name indexes started from 1, and
the primary source file was not explicit. Dwarf 5 standard (6.2.4) prescribes
the primary source file to be explicitly given an entry with an index number 0.
The current implementation honors the specification by just duplicating the
main source file, once with index number 0, and later maybe with another
index number. While this is compliant with the letter of the standard, the
duplication causes problems for consumers of this information such as lldb.
(Some files are duplicated, where only some of them have a line table although
all refer to the same file)
With this change, dwarf 5 debug line section files always start from 0, and
the zeroth entry is not duplicated whenever possible. This requires different
handling of dwarf 4 and dwarf 5 during generation (e.g. when a function returns
an index zero for a file name, it signals an error in dwarf 4, but not in dwarf
5) However, I think the minor complication is worth it, because it enables all
consumers (lldb, gdb, dwarfdump, objdump, and so on) to treat all files in the
file name list homogenously.
llvm-svn: 358732
This patch removes hidden codegen flag -print-schedule effectively reverting the
logic originally committed as r300311
(https://llvm.org/viewvc/llvm-project?view=revision&revision=300311).
Flag -print-schedule was originally introduced by r300311 to address PR32216
(https://bugs.llvm.org/show_bug.cgi?id=32216). That bug was about adding "Better
testing of schedule model instruction latencies/throughputs".
These days, we can use llvm-mca to test scheduling models. So there is no longer
a need for flag -print-schedule in LLVM. The main use case for PR32216 is
now addressed by llvm-mca.
Flag -print-schedule is mainly used for debugging purposes, and it is only
actually used by x86 specific tests. We already have extensive (latency and
throughput) tests under "test/tools/llvm-mca" for X86 processor models. That
means, most (if not all) existing -print-schedule tests for X86 are redundant.
When flag -print-schedule was first added to LLVM, several files had to be
modified; a few APIs gained new arguments (see for example method
MCAsmStreamer::EmitInstruction), and MCSubtargetInfo/TargetSubtargetInfo gained
a couple of getSchedInfoStr() methods.
Method getSchedInfoStr() had to originally work for both MCInst and
MachineInstr. The original implmentation of getSchedInfoStr() introduced a
subtle layering violation (reported as PR37160 and then fixed/worked-around by
r330615).
In retrospect, that new API could have been designed more optimally. We can
always query MCSchedModel to get the latency and throughput. More importantly,
the "sched-info" string should not have been generated by the subtarget.
Note, r317782 fixed an issue where "print-schedule" didn't work very well in the
presence of inline assembly. That commit is also reverted by this change.
Differential Revision: https://reviews.llvm.org/D57244
llvm-svn: 353043
N_FUNC_COLD is a new MachO symbol attribute. It's a hint to the linker
to order a symbol towards the end of its section, to improve locality.
Example:
```
void a1() {}
__attribute__((cold)) void a2() {}
void a3() {}
int main() {
a1();
a2();
a3();
return 0;
}
```
A linker that supports N_FUNC_COLD will order _a2 to the end of the text
section. From `nm -njU` output, we see:
```
_a1
_a3
_main
_a2
```
Differential Revision: https://reviews.llvm.org/D57190
llvm-svn: 352227
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
- When signing return addresses with -msign-return-address=<scope>{+<key>},
either the A key instructions or the B key instructions can be used. To
correctly authenticate the return address, the unwinder/debugger must know
which key was used to sign the return address.
- When and exception is thrown or a break point reached, it may be necessary to
unwind the stack. To accomplish this, the unwinder/debugger must be able to
first authenticate an the return address if it has been signed.
- To enable this, the augmentation string of CIEs has been extended to allow
inclusion of a 'B' character. Functions that are signed using the B key
variant of the instructions should have and FDE whose associated CIE has a 'B'
in the augmentation string.
- One must also be able to preserve these semantics when first stepping from a
high level language into assembly and then, as a second step, into an object
file. To achieve this, I have introduced a new assembly directive
'.cfi_b_key_frame ', that tells the assembler the current frame uses return
address signing with the B key.
- This ensures that the FDE is associated with a CIE that has 'B' in the
augmentation string.
Differential Revision: https://reviews.llvm.org/D51798
llvm-svn: 349895
Summary:
Add PLATFORM constants for iOS, tvOS, and watchOS simulators, as well
as human readable names for these constants, to the Mach-O file format
header files.
rdar://46854119
Reviewers: ab, davide
Reviewed By: ab, davide
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D55905
llvm-svn: 349779
- Reapply changes intially introduced in r343089
- The archtecture info is no longer loaded whenever a DWARFContext is created
- The runtimes libraries (santiziers) make use of the dwarf context classes but
do not intialise the target info
- The architecture of the object can be obtained without loading the target info
- Adding a method to the dwarf context to get this information and multiplex the
string printing later on
Differential Revision: https://reviews.llvm.org/D55774
llvm-svn: 349472
build version load commands in the object file
This commit introduces a new metadata node called "SDK Version". It will be set
by the frontend to mark the platform SDK (macOS/iOS/etc) version which was used
during that particular compilation.
This node is used when machine code is emitted, by either saving the SDK version
into the appropriate macho load command (version min/build version), or by
emitting the assembly for these load commands with the SDK version specified as
well.
The assembly for both load commands is extended by allowing it to contain the
sdk_version X, Y [, Z] trailing directive to represent the SDK version
respectively.
rdar://45774000
Differential Revision: https://reviews.llvm.org/D55612
llvm-svn: 349119
Add ARM64 unwind codes to MCLayer, as well SEH directives that will be emitted
by the frame lowering patch to follow. We only emit unwind codes into object
object files for now.
Differential Revision: https://reviews.llvm.org/D50166
llvm-svn: 345450
Summary:
If the target does not support `.asciz` and `.ascii` directives, the
strings are represented as bytes and each byte is placed on the new line
as a separate byte directive `.b8 <data>`. NVPTX target allows to
represent the vector of the data of the same type as a vector, where
values are separated using `,` symbol: `.b8 <data1>,<data2>,...`. This
allows to reduce the size of the final PTX file. Ptxas tool includes ptx
files into the resulting binary object, so reducing the size of the PTX
file is important.
Reviewers: tra, jlebar, echristo
Subscribers: jholewinski, llvm-commits
Differential Revision: https://reviews.llvm.org/D45822
llvm-svn: 345142
- Add fix so that all code paths that create DWARFContext
with an ObjectFile initialise the target architecture in the context
- Add an assert that the Arch is known in the Dwarf CallFrameString method
llvm-svn: 343317
This caused the DebugInfo/Sparc/gnu-window-save.ll test to fail.
> Functions that have signed return addresses need additional dwarf support:
> - After signing the LR, and before authenticating it, the LR register is in a
> state the is unusable by a debugger or unwinder
> - To account for this a new directive, .cfi_negate_ra_state, is added
> - This directive says the signed state of the LR register has now changed,
> i.e. unsigned -> signed or signed -> unsigned
> - This directive has the same CFA code as the SPARC directive GNU_window_save
> (0x2d), adding a macro to account for multiply defined codes
> - This patch matches the gcc implementation of this support:
> https://patchwork.ozlabs.org/patch/800271/
>
> Differential Revision: https://reviews.llvm.org/D50136
llvm-svn: 343103
Functions that have signed return addresses need additional dwarf support:
- After signing the LR, and before authenticating it, the LR register is in a
state the is unusable by a debugger or unwinder
- To account for this a new directive, .cfi_negate_ra_state, is added
- This directive says the signed state of the LR register has now changed,
i.e. unsigned -> signed or signed -> unsigned
- This directive has the same CFA code as the SPARC directive GNU_window_save
(0x2d), adding a macro to account for multiply defined codes
- This patch matches the gcc implementation of this support:
https://patchwork.ozlabs.org/patch/800271/
Differential Revision: https://reviews.llvm.org/D50136
llvm-svn: 343089
Now that we create the label at the point of the directive, we don't
need to set the "current CV location", and then later when we emit the
next instruction, create a label for it and emit it.
DWARF still defers the labels used in .debug_loc until the next
instruction or value, for reasons unknown.
llvm-svn: 340883
Even though gas doesn't document it, it has been supported there for
a very long time.
This produces the 32 bit relative virtual address (aka image relative
address) for a given symbol. ".rva foo" is essentially equal to
".long foo@imgrel".
Differential Revision: https://reviews.llvm.org/D49821
llvm-svn: 338063
The standard library functions ::isprint/std::isprint have platform-
and locale-dependent behavior which makes LLVM's output less
predictable. In particular, regression tests my fail depending on the
implementation of these functions.
Implement llvm::isPrint in StringExtras.h with a standard behavior and
replace all uses of ::isprint/std::isprint by a call it llvm::isPrint.
The function is inlined and does not look up language settings so it
should perform better than the standard library's version.
Such a replacement has already been done for isdigit, isalpha, isxdigit
in r314883. gtest does the same in gtest-printers.cc using the following
justification:
// Returns true if c is a printable ASCII character. We test the
// value of c directly instead of calling isprint(), which is buggy on
// Windows Mobile.
inline bool IsPrintableAscii(wchar_t c) {
return 0x20 <= c && c <= 0x7E;
}
Similar issues have also been encountered by Julia:
https://github.com/JuliaLang/julia/issues/7416
I noticed the problem myself when on Windows isprint('\t') started to
evaluate to true (see https://stackoverflow.com/questions/51435249) and
thus caused several unit tests to fail. The result of isprint doesn't
seem to be well-defined even for ASCII characters. Therefore I suggest
to replace isprint by a platform-independent version.
Differential Revision: https://reviews.llvm.org/D49680
llvm-svn: 338034
On darwin, all virtual sections have zerofill type, and having a
.zerofill directive in a non-virtual section is not allowed. Instead of
asserting, show a nicer error.
In order to use the equivalent of .zerofill in a non-virtual section,
the usage of .zero of .space is required.
This patch replaces the assert with an error.
Differential Revision: https://reviews.llvm.org/D48517
llvm-svn: 336127
In some cases, for example when compiling a preprocessed file, the
front-end is not able to provide an MD5 checksum for all files. When
that happens, omit the MD5 checksums from the final DWARF, because
DWARF doesn't have a way to indicate that some but not all files have
a checksum.
When assembling a .s file, and some but not all .file directives
provide an MD5 checksum, issue a warning and don't emit MD5 into the
DWARF.
Fixes PR37623.
Differential Revision: https://reviews.llvm.org/D48135
llvm-svn: 334710
On targets like Arm some relaxations may only be performed when certain
architectural features are available. As functions can be compiled with
differing levels of architectural support we must make a judgement on
whether we can relax based on the MCSubtargetInfo for the function. This
change passes through the MCSubtargetInfo for the function to
fixupNeedsRelaxation so that the decision on whether to relax can be made
per function. In this patch, only the ARM backend makes use of this
information. We must also pass the MCSubtargetInfo to applyFixup because
some fixups skip error checking on the assumption that relaxation has
occurred, to prevent code-generation errors applyFixup must see the same
MCSubtargetInfo as fixupNeedsRelaxation.
Differential Revision: https://reviews.llvm.org/D44928
llvm-svn: 334078
Summary:
Allow extended parsing of variable assembler assignment syntax and modify X86 to permit
VAR = register assignment. As we emit these as .set directives when possible, we inline
such expressions in output assembly.
Fixes PR37425.
Reviewers: rnk, void, echristo
Reviewed By: rnk
Subscribers: nickdesaulniers, llvm-commits, hiraditya
Differential Revision: https://reviews.llvm.org/D47545
llvm-svn: 334022
Object FIle Representation
At codegen time this is emitted into the ELF file a pair of symbol indices and a weight. In assembly it looks like:
.cg_profile a, b, 32
.cg_profile freq, a, 11
.cg_profile freq, b, 20
When writing an ELF file these are put into a SHT_LLVM_CALL_GRAPH_PROFILE (0x6fff4c02) section as (uint32_t, uint32_t, uint64_t) tuples as (from symbol index, to symbol index, weight).
Differential Revision: https://reviews.llvm.org/D44965
llvm-svn: 333823
Teach AsmParser to check with Assembler for when evaluating constant
expressions. This improves the handing of preprocessor expressions
that must be resolved at parse time. This idiom can be found as
assembling-time assertion checks in source-level assemblers. Note that
this relies on the MCStreamer to keep sufficient tabs on Section /
Fragment information which the MCAsmStreamer does not. As a result the
textual output may fail where the equivalent object generation would
pass. This can most easily be resolved by folding the MCAsmStreamer
and MCObjectStreamer together which is planned for in a separate
patch.
Currently, this feature is only enabled for assembly input, keeping IR
compilation consistent between assembly and object generation.
Reviewers: echristo, rnk, probinson, espindola, peter.smith
Reviewed By: peter.smith
Subscribers: eraman, peter.smith, arichardson, jyknight, hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D45164
llvm-svn: 331218
Previously the MD5 option of the .file directive provided the checksum
as a quoted hex string; now it's a normal hex number with 0x prefix,
same as the .octa directive accepts.
Differential Revision: https://reviews.llvm.org/D45459
llvm-svn: 329820
Summary:
Some targets do not support extended format of .loc directive and
support only simple format: .loc <FileID> <Line> <Column>. Patch adds
MCAsmInfo flag and option that allows emit .loc directive without
additional flags.
Reviewers: echristo
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D45184
llvm-svn: 329089
DWARF v5 specifies that the root file (also given in the DW_AT_name
attribute of the compilation unit DIE) should be emitted explicitly to
the line table's list of files. This makes the line table more
independent of the .debug_info section.
We emit the new syntax only for DWARF v5 and later.
Fixes the bug found by asan. Also XFAIL the new test for Darwin, which
is stuck on DWARF v2, and fix up other tests so they stop failing on
Windows. Last but not least, don't break "clang -g" of an assembler
file that has .file directives in it.
Differential Revision: https://reviews.llvm.org/D44054
llvm-svn: 328805
This reverts commit r328676.
Commit r328676 broke the -no-integrated-as flag necessary to build Linux kernel with Clang:
$ cat t.c
void foo() {}
$ clang -no-integrated-as -c t.c -g
/tmp/t-dcdec5.s: Assembler messages:
/tmp/t-dcdec5.s:8: Error: file number less than one
clang-7.0: error: assembler command failed with exit code 1 (use -v to see invocation)
llvm-svn: 328699
DWARF v5 specifies that the root file (also given in the DW_AT_name
attribute of the compilation unit DIE) should be emitted explicitly to
the line table's list of files. This makes the line table more
independent of the .debug_info section.
Fixes the bug found by asan. Also XFAIL the new test for Darwin, which
is stuck on DWARF v2, and fix up other tests so they stop failing on
Windows. Last but not least, don't break "clang -g" of an assembler
file that has .file directives in it.
Differential Revision: https://reviews.llvm.org/D44054
llvm-svn: 328676
On Hexagon "x = y" is a syntax used in most instructions, and is not
treated as a directive.
Differential Revision: https://reviews.llvm.org/D44256
llvm-svn: 328635
With this we only create an alias for @@@ once we know if it should
use @ or @@. This avoids last minutes renames and hacks to handle MS
names.
This only handles the ELF writer. LTO still has issues with @@@
aliases.
llvm-svn: 327160
This patch starts simplifying the handling of .symver.
For now it just moves the responsibility for creating an alias down to
the streamer. With that the asm streamer can pass a .symver unchanged,
which is nice since gas cannot parse "foo@bar = zed".
In a followup I hope to move the handling down to the writer so that
we don't need special hacks for avoiding breaking names with @@@ on
windows.
llvm-svn: 327101
Fixes the bug found by asan. Also XFAIL the new test for Darwin,
which is stuck on DWARF v2, and fix up other tests so they stop
failing on Windows.
llvm-svn: 326839
DWARF v5 specifies that the root file (also given in the DW_AT_name
attribute of the compilation unit DIE) should be emitted explicitly to
the line table's list of files. This makes the line table more
independent of the .debug_info section.
Differential Revision: https://reviews.llvm.org/D44054
llvm-svn: 326758
In DWARF v5 the Line Number Program Header is extensible, allowing values with
new content types. In this extension a content type is added,
DW_LNCT_LLVM_source, which contains the embedded source code of the file.
Add new optional attribute for !DIFile IR metadata called source which contains
source text. Use this to output the source to the DWARF line table of code
objects. Analogously extend METADATA_FILE in Bitcode and .file directive in ASM
to support optional source.
Teach llvm-dwarfdump and llvm-objdump about the new values. Update the output
format of llvm-dwarfdump to make room for the new attribute on file_names
entries, and support embedded sources for the -source option in llvm-objdump.
Differential Revision: https://reviews.llvm.org/D42765
llvm-svn: 325970
Ali Tamur