This code was incorrectly emitting extra bytes into arbitrary parts of
the object file when it was meant to be hashing them to compute the DWO
ID.
Follow-up patch(es) will refactor this API somewhat to make such bugs
harder to introduce, hopefully.
Significant missing hashing - as per the comment this was only meant to
skip member functions (unspecified, but I think it's legible as member
function declarations, not definitions) but was skipping all named
subprograms (so only hashed child DIEs for member function definitions -
because they didn't have a direct name, but only a name given indirectly
in the DW_AT_specification-referenced DIE)
- Extends the comments related to function descriptors, noting how they
are only used on AIX.
- Changes the condition used to gate the creation of the current function
symbol in AsmPrinter::SetupMachineFunction to reflect being AIX
specific. The creation of the symbol is different because of AIXs
linkage conventions, not because AIX uses function descriptors.
Differential Revision: https://reviews.llvm.org/D73115
Summary:
For -fpatchable-function-entry=N,0 -mbranch-protection=bti, after
9a24488cb67a90f889529987275c5e411ce01dda, we place the NOP sled after
the initial BTI.
```
.Lfunc_begin0:
bti c
nop
nop
.section __patchable_function_entries,"awo",@progbits,f,unique,0
.p2align 3
.xword .Lfunc_begin0
```
This patch adds a label after the initial BTI and changes the __patchable_function_entries entry to reference the label:
```
.Lfunc_begin0:
bti c
.Lpatch0:
nop
nop
.section __patchable_function_entries,"awo",@progbits,f,unique,0
.p2align 3
.xword .Lpatch0
```
This placement is compatible with the resolution in
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92424 .
A local linkage function whose address is not taken does not need a BTI.
Placing the patch label after BTI has the advantage that code does not
need to differentiate whether the function has an initial BTI.
Reviewers: mrutland, nickdesaulniers, nsz, ostannard
Subscribers: kristof.beyls, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D73680
For `MC_GlobalAddress` operands referencing **certain** GlobalObjects,
we can lower them to STB_LOCAL aliases to avoid costs brought by
assembler/linker's conservative decisions about symbol interposition:
* An assembler conservatively assumes a global default visibility symbol interposable (ELF
semantics). So relocations in object files are needed even if the code generator assumed
the definition exact and non-interposable.
* The relocations can cause the creation of PLT entries on some targets for -shared links.
A linker conservatively assumes a global default visibility symbol interposable (if not
otherwise constrained by -Bsymbolic/--dynamic-list/VER_NDX_LOCAL/etc).
"certain" refers to GlobalObjects in the intersection of
`hasExactDefinition() and !isInterposable()`: `external`, `appending`, `internal`, `private`.
Local linkages (`internal` and `private`) cannot be interposed. `appending` is for very
few objects LLVM interpret specially. So the set just includes `external`.
This patch emits STB_LOCAL aliases (.Lfoo$local) for such GlobalObjects, so that targets can lower
MC_GlobalAddress operands to STB_LOCAL aliases if applicable.
We may extend the scope and include GlobalAlias in the future.
LLVM's existing -fno-semantic-interposition behaviors give us license to do such optimizations:
* Various optimizations (ipconstprop, inliner, sccp, sroa, etc) treat normal ExternalLinkage
GlobalObjects as non-interposable.
* Before D72197, MC resolved a PC-relative VK_None fixup to a non-local symbol at assembly time (no
outstanding relocation), if the target is defined in the same section. Put it simply, even if IR
optimizations failed to optimize and allowed interposition for the function call in
`void foo() {} void bar() { foo(); }`, the assembler would disallow it.
This patch sets up AsmPrinter infrastructure to make -fno-semantic-interposition more so.
With and without the patch, the object file output should be identical:
`.Lfoo$local` does not take a symbol table entry.
Reviewed By: sfertile
Differential Revision: https://reviews.llvm.org/D73228
This is how it should've been and brings it more in line with
std::string_view. There should be no functional change here.
This is mostly mechanical from a custom clang-tidy check, with a lot of
manual fixups. It uncovers a lot of minor inefficiencies.
This doesn't actually modify StringRef yet, I'll do that in a follow-up.
This patch fixes an assertion failure in DwarfExpression that is
triggered when a complex fragment has exactly the size of a
subregister of the register the DBG_VALUE points to *and* there is no
DWARF encoding for the super-register.
I took the opportunity to replace/document some magic values with
static constructor functions to make this code less confusing to read.
rdar://problem/58489125
Differential Revision: https://reviews.llvm.org/D72938
This is a revert-of-revert (i.e. this reverts commit 802bec89, which
itself reverted fa4701e1 and 79daafc9) with a fix folded in. The problem
was that call site tags weren't emitted properly when LTO was enabled
along with split-dwarf. This required a minor fix. I've added a reduced
test case in test/DebugInfo/X86/fission-call-site.ll.
Original commit message:
This allows a call site tag in CU A to reference a callee DIE in CU B
without resorting to creating an incomplete duplicate DIE for the callee
inside of CU A.
We already allow cross-CU references of subprogram declarations, so it
doesn't seem like definitions ought to be special.
This improves entry value evaluation and tail call frame synthesis in
the LTO setting. During LTO, it's common for cross-module inlining to
produce a call in some CU A where the callee resides in a different CU,
and there is no declaration subprogram for the callee anywhere. In this
case llvm would (unnecessarily, I think) emit an empty DW_TAG_subprogram
in order to fill in the call site tag. That empty 'definition' defeats
entry value evaluation etc., because the debugger can't figure out what
it means.
As a follow-up, maybe we could add a DWARF verifier check that a
DW_TAG_subprogram at least has a DW_AT_name attribute.
Update #1:
Reland with a fix to create a declaration DIE when the declaration is
missing from the CU's retainedTypes list. The declaration is left out
of the retainedTypes list in two cases:
1) Re-compiling pre-r266445 bitcode (in which declarations weren't added
to the retainedTypes list), and
2) Doing LTO function importing (which doesn't update the retainedTypes
list).
It's possible to handle (1) and (2) by modifying the retainedTypes list
(in AutoUpgrade, or in the LTO importing logic resp.), but I don't see
an advantage to doing it this way, as it would cause more DWARF to be
emitted compared to creating the declaration DIEs lazily.
Update #2:
Fold in a fix for call site tag emission in the split-dwarf + LTO case.
Tested with a stage2 ThinLTO+RelWithDebInfo build of clang, and with a
ReleaseLTO-g build of the test suite.
rdar://46577651, rdar://57855316, rdar://57840415, rdar://58888440
Differential Revision: https://reviews.llvm.org/D70350
The Version was used only to determine the size of an operand of
DW_OP_call_ref. The size was 4 for all versions apart from 2, but
the DW_OP_call_ref operation was introduced only in DWARF3. Thus,
the code may be simplified and using of Version may be eliminated.
Differential Revision: https://reviews.llvm.org/D73264
Summary:
This fixes PR44118. For cases where we have a chain like this:
R8 = R1 (entry value)
R0 = R8
call @foo R0
the code that emits call site entries using entry values would not
follow that chain, instead emitting a call site entry with R8 as
location rather than R0. Such a case was discovered when originally
adding dbgcall-site-orr-moves.mir. This patch fixes that issue. This is
done by changing the ForwardedRegWorklist set to a map in which the
worklist registers always map to the parameter registers that they
describe.
Another thing this patch fixes is that worklist registers now can
describe more than one parameter register at a time. Such a case
occurred in dbgcall-site-interpretation.mir, resulting in a call site
entry not being emitted for one of the parameters.
Reviewers: djtodoro, NikolaPrica, aprantl, vsk
Reviewed By: vsk
Subscribers: hiraditya, llvm-commits
Tags: #debug-info, #llvm
Differential Revision: https://reviews.llvm.org/D73168
Summary:
Since D70431 the describeLoadedValue() hook takes a parameter register,
meaning that it can now be asked to describe any register. This means
that we can drop the difference between explicit and implicit defines
that we previously had in collectCallSiteParameters().
I have not found any case for any upstream targets where a parameter
register is only implicitly defined, and does not overlap with any
explicit defines. I don't know if such a case would even make sense. So
as far as I have tested, this patch should be a non-functional change.
However, this reduces the complexity of the code a bit, and it will
simplify the implementation of an upcoming patch which solves PR44118.
Reviewers: djtodoro, NikolaPrica, aprantl, vsk
Reviewed By: djtodoro, vsk
Subscribers: hiraditya, llvm-commits
Tags: #debug-info, #llvm
Differential Revision: https://reviews.llvm.org/D73167
... as well as:
Revert "[DWARF] Defer creating declaration DIEs until we prepare call site info"
This reverts commit fa4701e1979553c2df61698ac1ac212627630442.
This reverts commit 79daafc90308787b52a5d3a7586e82acd5e374b3.
There have been reports of this assert getting hit:
CalleeDIE && "Could not find DIE for call site entry origin
Summary:
This is a follow up on https://reviews.llvm.org/D71473#inline-647262.
There's a caveat here that `Align(1)` relies on the compiler understanding of `Log2_64` implementation to produce good code. One could use `Align()` as a replacement but I believe it is less clear that the alignment is one in that case.
Reviewers: xbolva00, courbet, bollu
Subscribers: arsenm, dylanmckay, sdardis, nemanjai, jvesely, nhaehnle, hiraditya, kbarton, jrtc27, atanasyan, jsji, Jim, kerbowa, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D73099
Similar to the function attribute `prefix` (prefix data),
"patchable-function-prefix" inserts data (M NOPs) before the function
entry label.
-fpatchable-function-entry=2,1 (1 NOP before entry, 1 NOP after entry)
will look like:
```
.type foo,@function
.Ltmp0: # @foo
nop
foo:
.Lfunc_begin0:
# optional `bti c` (AArch64 Branch Target Identification) or
# `endbr64` (Intel Indirect Branch Tracking)
nop
.section __patchable_function_entries,"awo",@progbits,get,unique,0
.p2align 3
.quad .Ltmp0
```
-fpatchable-function-entry=N,0 + -mbranch-protection=bti/-fcf-protection=branch has two reasonable
placements (https://gcc.gnu.org/ml/gcc-patches/2020-01/msg01185.html):
```
(a) (b)
func: func:
.Ltmp0: bti c
bti c .Ltmp0:
nop nop
```
(a) needs no additional code. If the consensus is to go for (b), we will
need more code in AArch64BranchTargets.cpp / X86IndirectBranchTracking.cpp .
Differential Revision: https://reviews.llvm.org/D73070
The low_pc is analog to the DW_AT_call_return_pc, since it describes
the return address after the call. The DW_AT_call_pc is the address
of the call instruction, and we don't use it at the moment.
Differential Revision: https://reviews.llvm.org/D73173
Summary:
This was reverted in 328e0f3dcac52171b8cdedeaba22c98e7fbb75ea due to
chromium bot failure. This revision addresses that case.
Original commit message:
Summary:
This patch will provide support for auto return type for the C++ member
functions. Before this return type of the member function is deduced and
stored in the DIE.
This patch includes llvm side implementation of this feature.
Patch by: Awanish Pandey <Awanish.Pandey@amd.com>
Reviewers: dblaikie, aprantl, shafik, alok, SouraVX, jini.susan.george
Reviewed by: dblaikie
Differential Revision: https://reviews.llvm.org/D70524
This makes the SectionLabel handling more resilient - specifically for
future PROPELLER work which will have more CU ranges (rather than just
one per function).
Ultimately it might be nice to make this more general/resilient to
arbitrary labels (rather than relying on the labels being created for CU
ranges & then being reused by ranges, loclists, and possibly other
addresses). It's possible that other (non-rnglist/loclist) uses of
addresses will need the addresses to be in SectionLabels earlier (eg:
move the CU.addRange to be done on function begin, rather than function
end, so during function emission they are already populated for other
use).
This change has 2 components:
Target-independent: add a method getDwarfFrameBase to TargetFrameLowering. It
describes how the Dwarf frame base will be encoded. That can be a register (the
default), the CFA (which replaces NVPTX-specific logic in DwarfCompileUnit), or
a DW_OP_WASM_location descriptr.
WebAssembly: Allow WebAssemblyFunctionInfo::getFrameRegister to return the
correct virtual register instead of FP32/SP32 after WebAssemblyReplacePhysRegs
has run. Make WebAssemblyExplicitLocals store the local it allocates for the
frame register. Use this local information to implement getDwarfFrameBase
The result is that the DW_AT_frame_base attribute is correctly encoded for each
subprogram, and each param and local variable has a correct DW_AT_location that
uses DW_OP_fbreg to refer to the frame base.
This is a reland of rG3a05c3969c18 with fixes for the expensive-checks
and Windows builds
Differential Revision: https://reviews.llvm.org/D71681
[this re-applies c0176916a4824812d25a5a22c4ff7c95857b0cd6
with the correct commit message and phabricator link]
This addresses point 1 of PR44213.
https://bugs.llvm.org/show_bug.cgi?id=44213
The DW_AT_LLVM_sysroot attribute is used for Clang module debug info,
to allow LLDB to import a Clang module from source. Currently it is
part of each DW_TAG_module, however, it is the same for all modules in
a compile unit. It is more efficient and less ambiguous to store it
once in the DW_TAG_compile_unit.
This should have no effect on DWARF consumers other than LLDB.
Differential Revision: https://reviews.llvm.org/D71732
This is a purely cosmetic change that is NFC in terms of the binary
output. I bugs me that I called the attribute DW_AT_LLVM_isysroot
since the "i" is an artifact of GCC command line option syntax
(-isysroot is in the category of -i options) and doesn't carry any
useful information otherwise.
This attribute only appears in Clang module debug info.
Differential Revision: https://reviews.llvm.org/D71722
This change has 2 components:
Target-independent: add a method getDwarfFrameBase to TargetFrameLowering. It
describes how the Dwarf frame base will be encoded. That can be a register (the
default), the CFA (which replaces NVPTX-specific logic in DwarfCompileUnit), or
a DW_OP_WASM_location descriptr.
WebAssembly: Allow WebAssemblyFunctionInfo::getFrameRegister to return the
correct virtual register instead of FP32/SP32 after WebAssemblyReplacePhysRegs
has run. Make WebAssemblyExplicitLocals store the local it allocates for the
frame register. Use this local information to implement getDwarfFrameBase
The result is that the DW_AT_frame_base attribute is correctly encoded for each
subprogram, and each param and local variable has a correct DW_AT_location that
uses DW_OP_fbreg to refer to the frame base.
Differential Revision: https://reviews.llvm.org/D71681
This reverts D53469, which changed llvm's DWARF emission to emit
DW_AT_call_return_pc as a function-local offset. Such an encoding is not
compatible with post-link block re-ordering tools and isn't standards-
compliant.
In addition to reverting back to the original DW_AT_call_return_pc
encoding, teach lldb how to fix up DW_AT_call_return_pc when the address
comes from an object file pointed-to by a debug map. While doing this I
noticed that lldb's support for tail calls that cross a DSO/object file
boundary wasn't covered, so I added tests for that. This latter case
exercises the newly added return PC fixup.
The dsymutil changes in this patch were originally included in D49887:
the associated test should be sufficient to test DW_AT_call_return_pc
encoding purely on the llvm side.
Differential Revision: https://reviews.llvm.org/D72489
Summary:
This patch will provide support for auto return type for the C++ member
functions. Before this return type of the member function is deduced and
stored in the DIE.
This patch includes llvm side implementation of this feature.
Patch by: Awanish Pandey <Awanish.Pandey@amd.com>
Reviewers: dblaikie, aprantl, shafik, alok, SouraVX, jini.susan.george
Reviewed by: dblaikie
Differential Revision: https://reviews.llvm.org/D70524
.section name, "flags"G, @type, GroupName[, linkage]
As of binutils 2.33, linkage cannot be 'unique'. For integrated
assembler, we use both 'o' flag and 'unique' linkage to support
--gc-sections and COMDAT with lld.
https://sourceware.org/ml/binutils/2019-11/msg00266.html
The Linux kernel uses -fpatchable-function-entry to implement DYNAMIC_FTRACE_WITH_REGS
for arm64 and parisc. GCC 8 implemented
-fpatchable-function-entry, which can be seen as a generalized form of
-mnop-mcount. The N,M form (function entry points before the Mth NOP) is
currently only used by parisc.
This patch adds N,0 support to AArch64 codegen. N is represented as the
function attribute "patchable-function-entry". We will use a different
function attribute for M, if we decide to implement it.
The patch reuses the existing patchable-function pass, and
TargetOpcode::PATCHABLE_FUNCTION_ENTER which is currently used by XRay.
When the integrated assembler is used, __patchable_function_entries will
be created for each text section with the SHF_LINK_ORDER flag to prevent
--gc-sections (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93197) and
COMDAT (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93195) issues.
Retrospectively, __patchable_function_entries should use a PC-relative
relocation type to avoid the SHF_WRITE flag and dynamic relocations.
"patchable-function-entry"'s interaction with Branch Target
Identification is still unclear (see
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92424 for GCC discussions).
Reviewed By: peter.smith
Differential Revision: https://reviews.llvm.org/D72215
Summary:
It's not necessary to use an 'l'(ell) modifier when referencing a label.
Treat block addresses and MBB references as if the modifier is used
anyway. This prevents us from generating references to ficticious
labels.
Reviewers: jyknight, nickdesaulniers, hfinkel
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D71849
Summary:
This is documented as the appropriate template modifier for call operands.
Fixes PR44272, and adds a regression test.
Also adds support for operand modifiers in Intel-style inline assembly.
Reviewers: rnk
Reviewed By: rnk
Subscribers: merge_guards_bot, hiraditya, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D71677
It isn't necessary to create DIEs for all of the declaration subprograms
in a CU's retainedTypes list. We can defer creating these subprograms
until we need to prepare a call site tag that refers to one.
This cleanup was mentioned in passing in D70350.
This allows a call site tag in CU A to reference a callee DIE in CU B
without resorting to creating an incomplete duplicate DIE for the callee
inside of CU A.
We already allow cross-CU references of subprogram declarations, so it
doesn't seem like definitions ought to be special.
This improves entry value evaluation and tail call frame synthesis in
the LTO setting. During LTO, it's common for cross-module inlining to
produce a call in some CU A where the callee resides in a different CU,
and there is no declaration subprogram for the callee anywhere. In this
case llvm would (unnecessarily, I think) emit an empty DW_TAG_subprogram
in order to fill in the call site tag. That empty 'definition' defeats
entry value evaluation etc., because the debugger can't figure out what
it means.
As a follow-up, maybe we could add a DWARF verifier check that a
DW_TAG_subprogram at least has a DW_AT_name attribute.
Update:
Reland with a fix to create a declaration DIE when the declaration is
missing from the CU's retainedTypes list. The declaration is left out
of the retainedTypes list in two cases:
1) Re-compiling pre-r266445 bitcode (in which declarations weren't added
to the retainedTypes list), and
2) Doing LTO function importing (which doesn't update the retainedTypes
list).
It's possible to handle (1) and (2) by modifying the retainedTypes list
(in AutoUpgrade, or in the LTO importing logic resp.), but I don't see
an advantage to doing it this way, as it would cause more DWARF to be
emitted compared to creating the declaration DIEs lazily.
Tested with a stage2 ThinLTO+RelWithDebInfo build of clang, and with a
ReleaseLTO-g build of the test suite.
rdar://46577651, rdar://57855316, rdar://57840415
Differential Revision: https://reviews.llvm.org/D70350
Extends DWARF expression language to express locals/globals locations. (via
target-index operands atm) (possible variants are: non-virtual registers
or address spaces)
The WebAssemblyExplicitLocals can replace virtual registers to targertindex
operand type at the time when WebAssembly backend introduces
{get,set,tee}_local instead of corresponding virtual registers.
Reviewed By: aprantl, dschuff
Tags: #debug-info, #llvm
Differential Revision: https://reviews.llvm.org/D52634
This is a purely cosmetic change that is NFC in terms of the binary
output. I bugs me that I called the attribute DW_AT_LLVM_isysroot
since the "i" is an artifact of GCC command line option syntax
(-isysroot is in the category of -i options) and doesn't carry any
useful information otherwise.
This attribute only appears in Clang module debug info.
Differential Revision: https://reviews.llvm.org/D71722
The calculator was considering instructions such as KILLs as clobbers
of a physical address. This is wrong as meta instructions such as KILLs
produce no output in the final program and thus don't clobber or change
any physical location's value. As a result they're safe to ignore whilst
calculating location list ranges.
reviewers: aprantl, vsk
diff revision: https://reviews.llvm.org/D70497
fixes: https://bugs.llvm.org/show_bug.cgi?id=38753
Since the address pool doesn't get populated in this case (due to the
lack of inlining, no child DIEs are added to the CU - so no addresses
are needed for the DIEs themselves) until the range list is emitted - at
the time the attributes are added to the CU, the address pool is empty.
So check whether the address pool will be used for the range lists & add
an addr_base if that's the case.
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.
added a test case for macinfo.dwo emission."
This was reverted in caa412090666c10f854322cdc701c1cbf8ed726e,
since it was causing an assertion failure on Windows bots.
This revision is revised to fix that.
Original commit message -
[DebugInfo] Refactored macro related generation, added a test case for macinfo.dwo emission.
Reviewers: dblaikie, aprantl, jini.susan.george
Tags: #debug-info #llvm
Differential Revision: https://reviews.llvm.org/D71008
Summary:
With DWARF5 it is no longer possible to distinguish normal methods and methods with `__attribute__((objc_direct))` by just looking at the debug information
as they are both now children of the of the DW_TAG_structure_type that defines them (before only the `__attribute__((objc_direct))` methods were children).
This means that in LLDB we are no longer able to create a correct Clang AST of a module by just looking at the debug information. Instead we would
need to call the Objective-C runtime to see which of the methods have a `__attribute__((objc_direct))` and then add the attribute to our own Clang AST
depending on what the runtime returns. This would mean that we either let the module AST be dependent on the Objective-C runtime (which doesn't
seem right) or we retroactively add the missing attribute to the imported AST in our expressions.
A third option is to annotate methods with `__attribute__((objc_direct))` as `DW_AT_APPLE_objc_direct` which is what this patch implements. This way
LLDB doesn't have to call the runtime for any `__attribute__((objc_direct))` method and the AST in our module will already be correct when we create it.
Reviewers: aprantl, SouraVX
Reviewed By: aprantl
Subscribers: hiraditya, cfe-commits, llvm-commits
Tags: #clang, #llvm, #debug-info
Differential Revision: https://reviews.llvm.org/D71201
