Commit Graph

4474 Commits

Author SHA1 Message Date
Kazu Hirata 1d0bc05551 [llvm] Use llvm::append_range (NFC) 2021-01-06 18:27:33 -08:00
Sam Clegg 30d314aae1 [MC][WebAssembly] Avoid recalculating indexes in -gsplit-dwarf mode
Be consistent about asserting before setting WasmIndices.  Adding
these assertions revealed that we were duplicating a lot of work
and setting these indexed twice when running in DWO mode.

Differential Revision: https://reviews.llvm.org/D93650
2021-01-06 01:35:06 -08:00
Andy Wingo 9ad83fd6dc [WebAssembly] call_indirect causes indirect function table import
For wasm-ld table linking work to proceed, object files should indicate
if they use an indirect function table.  In the future this will be done
by the usual symbols and relocations mechanism, but until that support
lands in the linker, the presence of an `__indirect_function_table` in
the object file's import section shows that the object file needs an
indirect function table.

Prior to https://reviews.llvm.org/D91637, this condition was met by all
object files residualizing an `__indirect_function_table` import.

Since https://reviews.llvm.org/D91637, the intention has been that only
those object files needing an indirect function table would have the
`__indirect_function_table` import.  However, we missed the case of
object files which use the table via `call_indirect` but which
themselves do not declare any indirect functions.

This changeset makes it so that when we lower a call to `call_indirect`,
that we ensure that a `__indirect_function_table` symbol is present and
that it will be propagated to the linker.

A followup patch will revise this mechanism to make an explicit link
between `call_indirect` and its associated indirect function table; see
https://reviews.llvm.org/D90948.

Differential Revision: https://reviews.llvm.org/D92840
2021-01-05 11:09:24 +01:00
Fangrui Song d9a0c40bce [MC] Split MCContext::createTempSymbol, default AlwaysAddSuffix to true, and add comments
CanBeUnnamed is rarely false. Splitting to a createNamedTempSymbol makes the
intention clearer and matches the direction of reverted r240130 (to drop the
unneeded parameters).

No behavior change.
2020-12-21 14:04:13 -08:00
Fangrui Song 8ffda237a6 MCContext::reportError: don't call report_fatal_error
Errors from MCAssembler, MCObjectStreamer and *ObjectWriter typically cause a crash:

```
% cat c.c
int bar;
extern int foo __attribute__((alias("bar")));
% clang -c -fcommon c.c
fatal error: error in backend: Common symbol 'bar' cannot be used in assignment expr
PLEASE submit a bug report to ...
Stack dump:
...
```

`LLVMTargetMachine::addPassesToEmitFile` constructs `MachineModuleInfoWrapperPass`
which creates a MCContext without SourceMgr. `MCContext::reportError` calls
`report_fatal_error` which gets captured by Clang `LLVMErrorHandler` and gets translated
to the output above.

Since `MCContext::reportError` errors indicate user errors, such a crashing style error
is inappropriate. So this patch changes `report_fatal_error` to `SourceMgr().PrintMessage`.
```
% clang -c -fcommon c.c
<unknown>:0: error: Common symbol 'bar' cannot be used in assignment expr
```

Ideally we should at least recover the original filename (the line information
is generally lost).  That requires general improvement to MC diagnostics,
because currently in many cases SMLoc information is lost.
2020-12-20 23:23:12 -08:00
Jian Cai e0963ae274 [AsmParser] make .ascii support spaces as separators
Currently the integrated assembler only allows commas as the separator
between string arguments in .ascii. This patch adds support to using
space as separators and make IAS consistent with GNU assembler.

Link: https://github.com/ClangBuiltLinux/linux/issues/1196

Reviewed By: nickdesaulniers, jrtc27

Differential Revision: https://reviews.llvm.org/D91460
2020-12-20 22:41:00 -08:00
Fangrui Song 7b9890e17e [MC][ELF] Remove unneeded MCSymbol::setExternal calls
ELF code uses symbol bindings and does not call isExternal().
2020-12-20 21:26:36 -08:00
Fangrui Song e4c360a897 [MC][ELF] Drop MCSymbol::isExternal call sites
ELF uses symbol bindings and MCSymbol::isExternal is not really useful.
The function is no longer used in ELF code now.
2020-12-20 21:18:22 -08:00
Fangrui Song 553d4d08d2 [MC] Report locations for .symver errors 2020-12-20 21:04:12 -08:00
Fangrui Song 72e75ca343 [MC][ELF] Allow STT_SECTION referencing SHF_MERGE on REL targets
This relands D64327 with a more specific workaround for R_386_GOTOFF
(gold<2.34 bug https://sourceware.org/bugzilla/show_bug.cgi?id=16794)

.debug_info has quite a few .debug_str relocations (R_386_32/R_ARM_ABS32).
The original workaround was too general and introduced too many .L symbols
used just as relocation targets.

From the original review:

  ... it reduced the size of a big ARM-32 debug image by 33%. It contained ~68M
  of relocations symbols out of total ~71M symbols (96% of symbols table was
  generated for relocations with symbol).
2020-12-20 18:37:14 -08:00
Fangrui Song 01d1de8196 [MC] Reject byte alignment if larger than or equal to 2**32
This is consistent with the resolution to power-of-2 alignments.
Otherwise, emitCodeAlignment and emitValueToAlignment cannot handle alignments
larger than 2**32 and will trigger assertion failure (PR35218).

Note: GNU as as of 2.35 will use 1 for such a large byte `.align`
2020-12-20 14:17:00 -08:00
Tobias Burnus 1deff4009e [MC][ELF] Accept abbreviated form with sh_flags and sh_entsize
D73999 / commit 75af9da755
added for LLVM 11 a check that sh_flags and sh_entsize (and sh_type)
changes are an error, in line with GNU assembler.

However, GNU assembler accepts and GCC generates an abbreviated form:
while the first .section contains the flags and entsize, subsequent
sections simply contain the name without repeating entsize or flags.

Do likewise for better compatibility.

See https://bugs.llvm.org/show_bug.cgi?id=48201

Reviewed By: jhenderson, MaskRay

Differential Revision: https://reviews.llvm.org/D92052
2020-12-11 16:45:45 +00:00
Hongtao Yu 705a4c149d [CSSPGO] Pseudo probe encoding and emission.
This change implements pseudo probe encoding and emission for CSSPGO. Please see RFC here for more context: https://groups.google.com/g/llvm-dev/c/1p1rdYbL93s

Pseudo probes are in the form of intrinsic calls on IR/MIR but they do not turn into any machine instructions. Instead they are emitted into the binary as a piece of data in standalone sections.  The probe-specific sections are not needed to be loaded into memory at execution time, thus they do not incur a runtime overhead. 

**ELF object emission**

The binary data to emit are organized as two ELF sections, i.e, the `.pseudo_probe_desc` section and the `.pseudo_probe` section. The `.pseudo_probe_desc` section stores a function descriptor for each function and the `.pseudo_probe` section stores the actual probes, each fo which corresponds to an IR basic block or an IR function callsite. A function descriptor is stored as a module-level metadata during the compilation and is serialized into the object file during object emission.

Both the probe descriptors and pseudo probes can be emitted into a separate ELF section per function to leverage the linker for deduplication.  A `.pseudo_probe` section shares the same COMDAT group with the function code so that when the function is dead, the probes are dead and disposed too. On the contrary, a `.pseudo_probe_desc` section has its own COMDAT group. This is because even if a function is dead, its probes may be inlined into other functions and its descriptor is still needed by the profile generation tool.

The format of `.pseudo_probe_desc` section looks like:

```
.section   .pseudo_probe_desc,"",@progbits
.quad   6309742469962978389  // Func GUID
.quad   4294967295           // Func Hash
.byte   9                    // Length of func name
.ascii  "_Z5funcAi"          // Func name
.quad   7102633082150537521
.quad   138828622701
.byte   12
.ascii  "_Z8funcLeafi"
.quad   446061515086924981
.quad   4294967295
.byte   9
.ascii  "_Z5funcBi"
.quad   -2016976694713209516
.quad   72617220756
.byte   7
.ascii  "_Z3fibi"
```

For each `.pseudoprobe` section, the encoded binary data consists of a single function record corresponding to an outlined function (i.e, a function with a code entry in the `.text` section). A function record has the following format :

```
FUNCTION BODY (one for each outlined function present in the text section)
    GUID (uint64)
        GUID of the function
    NPROBES (ULEB128)
        Number of probes originating from this function.
    NUM_INLINED_FUNCTIONS (ULEB128)
        Number of callees inlined into this function, aka number of
        first-level inlinees
    PROBE RECORDS
        A list of NPROBES entries. Each entry contains:
          INDEX (ULEB128)
          TYPE (uint4)
            0 - block probe, 1 - indirect call, 2 - direct call
          ATTRIBUTE (uint3)
            reserved
          ADDRESS_TYPE (uint1)
            0 - code address, 1 - address delta
          CODE_ADDRESS (uint64 or ULEB128)
            code address or address delta, depending on ADDRESS_TYPE
    INLINED FUNCTION RECORDS
        A list of NUM_INLINED_FUNCTIONS entries describing each of the inlined
        callees.  Each record contains:
          INLINE SITE
            GUID of the inlinee (uint64)
            ID of the callsite probe (ULEB128)
          FUNCTION BODY
            A FUNCTION BODY entry describing the inlined function.
```

To support building a context-sensitive profile, probes from inlinees are grouped by their inline contexts. An inline context is logically a call path through which a callee function lands in a caller function. The probe emitter builds an inline tree based on the debug metadata for each outlined function in the form of a trie tree. A tree root is the outlined function. Each tree edge stands for a callsite where inlining happens. Pseudo probes originating from an inlinee function are stored in a tree node and the tree path starting from the root all the way down to the tree node is the inline context of the probes. The emission happens on the whole tree top-down recursively. Probes of a tree node will be emitted altogether with their direct parent edge. Since a pseudo probe corresponds to a real code address, for size savings, the address is encoded as a delta from the previous probe except for the first probe. Variant-sized integer encoding, aka LEB128, is used for address delta and probe index.

**Assembling**

Pseudo probes can be printed as assembly directives alternatively. This allows for good assembly code readability and also provides a view of how optimizations and pseudo probes affect each other, especially helpful for diff time assembly analysis.

A pseudo probe directive has the following operands in order: function GUID, probe index, probe type, probe attributes and inline context. The directive is generated by the compiler and can be parsed by the assembler to form an encoded `.pseudoprobe` section in the object file.

A example assembly looks like:

```
foo2: # @foo2
# %bb.0: # %bb0
pushq %rax
testl %edi, %edi
.pseudoprobe 837061429793323041 1 0 0
je .LBB1_1
# %bb.2: # %bb2
.pseudoprobe 837061429793323041 6 2 0
callq foo
.pseudoprobe 837061429793323041 3 0 0
.pseudoprobe 837061429793323041 4 0 0
popq %rax
retq
.LBB1_1: # %bb1
.pseudoprobe 837061429793323041 5 1 0
callq *%rsi
.pseudoprobe 837061429793323041 2 0 0
.pseudoprobe 837061429793323041 4 0 0
popq %rax
retq
# -- End function
.section .pseudo_probe_desc,"",@progbits
.quad 6699318081062747564
.quad 72617220756
.byte 3
.ascii "foo"
.quad 837061429793323041
.quad 281547593931412
.byte 4
.ascii "foo2"
```

With inlining turned on, the assembly may look different around %bb2 with an inlined probe:

```
# %bb.2:                                # %bb2
.pseudoprobe    837061429793323041 3 0
.pseudoprobe    6699318081062747564 1 0 @ 837061429793323041:6
.pseudoprobe    837061429793323041 4 0
popq    %rax
retq
```

**Disassembling**

We have a disassembling tool (llvm-profgen) that can display disassembly alongside with pseudo probes. So far it only supports ELF executable file.

An example disassembly looks like:

```
00000000002011a0 <foo2>:
  2011a0: 50                    push   rax
  2011a1: 85 ff                 test   edi,edi
  [Probe]:  FUNC: foo2  Index: 1  Type: Block
  2011a3: 74 02                 je     2011a7 <foo2+0x7>
  [Probe]:  FUNC: foo2  Index: 3  Type: Block
  [Probe]:  FUNC: foo2  Index: 4  Type: Block
  [Probe]:  FUNC: foo   Index: 1  Type: Block  Inlined: @ foo2:6
  2011a5: 58                    pop    rax
  2011a6: c3                    ret
  [Probe]:  FUNC: foo2  Index: 2  Type: Block
  2011a7: bf 01 00 00 00        mov    edi,0x1
  [Probe]:  FUNC: foo2  Index: 5  Type: IndirectCall
  2011ac: ff d6                 call   rsi
  [Probe]:  FUNC: foo2  Index: 4  Type: Block
  2011ae: 58                    pop    rax
  2011af: c3                    ret
```

Reviewed By: wmi

Differential Revision: https://reviews.llvm.org/D91878
2020-12-10 17:29:28 -08:00
Derek Schuff 8d396acac3 [WebAssembly] Support COMDAT sections in assembly syntax
This CL changes the asm syntax for section flags, making them more like ELF
(previously "passive" was the only option). Now we also allow "G" to designate
COMDAT group sections. In these sections we set the appropriate comdat flag on
function symbols, and also avoid auto-creating a new section for them.

This also adds asm-based tests for the changes D92691 to go along with
the direct-to-object tests.

Differential Revision: https://reviews.llvm.org/D92952
This is a reland of rG4564553b8d8a with a fix to the lit pipeline in
llvm/test/MC/WebAssembly/comdat.ll
2020-12-10 16:43:59 -08:00
Derek Schuff dd1aa4fdd8 Revert "[WebAssembly] Support COMDAT sections in assembly syntax"
This reverts commit 4564553b8d.
It broke several buildbots.
2020-12-10 15:55:33 -08:00
Mitch Phillips 7ead5f5aa3 Revert "[CSSPGO] Pseudo probe encoding and emission."
This reverts commit b035513c06.

Reason: Broke the ASan buildbots:
  http://lab.llvm.org:8011/#/builders/5/builds/2269
2020-12-10 15:53:39 -08:00
Mitch Phillips b955eb688d Revert "[NFC] Fix a gcc build break by using an explict constructor."
This reverts commit 248b279cf0.

Reason: Dependency of patch that broke the ASan buildbots:
  http://lab.llvm.org:8011/#/builders/5/builds/2269
2020-12-10 15:53:38 -08:00
Derek Schuff 4564553b8d [WebAssembly] Support COMDAT sections in assembly syntax
This CL changes the asm syntax for section flags, making them more like ELF
(previously "passive" was the only option). Now we also allow "G" to designate
COMDAT group sections. In these sections we set the appropriate comdat flag on
function symbols, and also avoid auto-creating a new section for them.

This also adds asm-based tests for the changes D92691 to go along with
the direct-to-object tests.

Differential Revision: https://reviews.llvm.org/D92952
2020-12-10 14:46:24 -08:00
Hongtao Yu 248b279cf0 [NFC] Fix a gcc build break by using an explict constructor. 2020-12-10 11:21:40 -08:00
Hongtao Yu b035513c06 [CSSPGO] Pseudo probe encoding and emission.
This change implements pseudo probe encoding and emission for CSSPGO. Please see RFC here for more context: https://groups.google.com/g/llvm-dev/c/1p1rdYbL93s

Pseudo probes are in the form of intrinsic calls on IR/MIR but they do not turn into any machine instructions. Instead they are emitted into the binary as a piece of data in standalone sections.  The probe-specific sections are not needed to be loaded into memory at execution time, thus they do not incur a runtime overhead. 

**ELF object emission**

The binary data to emit are organized as two ELF sections, i.e, the `.pseudo_probe_desc` section and the `.pseudo_probe` section. The `.pseudo_probe_desc` section stores a function descriptor for each function and the `.pseudo_probe` section stores the actual probes, each fo which corresponds to an IR basic block or an IR function callsite. A function descriptor is stored as a module-level metadata during the compilation and is serialized into the object file during object emission.

Both the probe descriptors and pseudo probes can be emitted into a separate ELF section per function to leverage the linker for deduplication.  A `.pseudo_probe` section shares the same COMDAT group with the function code so that when the function is dead, the probes are dead and disposed too. On the contrary, a `.pseudo_probe_desc` section has its own COMDAT group. This is because even if a function is dead, its probes may be inlined into other functions and its descriptor is still needed by the profile generation tool.

The format of `.pseudo_probe_desc` section looks like:

```
.section   .pseudo_probe_desc,"",@progbits
.quad   6309742469962978389  // Func GUID
.quad   4294967295           // Func Hash
.byte   9                    // Length of func name
.ascii  "_Z5funcAi"          // Func name
.quad   7102633082150537521
.quad   138828622701
.byte   12
.ascii  "_Z8funcLeafi"
.quad   446061515086924981
.quad   4294967295
.byte   9
.ascii  "_Z5funcBi"
.quad   -2016976694713209516
.quad   72617220756
.byte   7
.ascii  "_Z3fibi"
```

For each `.pseudoprobe` section, the encoded binary data consists of a single function record corresponding to an outlined function (i.e, a function with a code entry in the `.text` section). A function record has the following format :

```
FUNCTION BODY (one for each outlined function present in the text section)
    GUID (uint64)
        GUID of the function
    NPROBES (ULEB128)
        Number of probes originating from this function.
    NUM_INLINED_FUNCTIONS (ULEB128)
        Number of callees inlined into this function, aka number of
        first-level inlinees
    PROBE RECORDS
        A list of NPROBES entries. Each entry contains:
          INDEX (ULEB128)
          TYPE (uint4)
            0 - block probe, 1 - indirect call, 2 - direct call
          ATTRIBUTE (uint3)
            reserved
          ADDRESS_TYPE (uint1)
            0 - code address, 1 - address delta
          CODE_ADDRESS (uint64 or ULEB128)
            code address or address delta, depending on ADDRESS_TYPE
    INLINED FUNCTION RECORDS
        A list of NUM_INLINED_FUNCTIONS entries describing each of the inlined
        callees.  Each record contains:
          INLINE SITE
            GUID of the inlinee (uint64)
            ID of the callsite probe (ULEB128)
          FUNCTION BODY
            A FUNCTION BODY entry describing the inlined function.
```

To support building a context-sensitive profile, probes from inlinees are grouped by their inline contexts. An inline context is logically a call path through which a callee function lands in a caller function. The probe emitter builds an inline tree based on the debug metadata for each outlined function in the form of a trie tree. A tree root is the outlined function. Each tree edge stands for a callsite where inlining happens. Pseudo probes originating from an inlinee function are stored in a tree node and the tree path starting from the root all the way down to the tree node is the inline context of the probes. The emission happens on the whole tree top-down recursively. Probes of a tree node will be emitted altogether with their direct parent edge. Since a pseudo probe corresponds to a real code address, for size savings, the address is encoded as a delta from the previous probe except for the first probe. Variant-sized integer encoding, aka LEB128, is used for address delta and probe index.

**Assembling**

Pseudo probes can be printed as assembly directives alternatively. This allows for good assembly code readability and also provides a view of how optimizations and pseudo probes affect each other, especially helpful for diff time assembly analysis.

A pseudo probe directive has the following operands in order: function GUID, probe index, probe type, probe attributes and inline context. The directive is generated by the compiler and can be parsed by the assembler to form an encoded `.pseudoprobe` section in the object file.

A example assembly looks like:

```
foo2: # @foo2
# %bb.0: # %bb0
pushq %rax
testl %edi, %edi
.pseudoprobe 837061429793323041 1 0 0
je .LBB1_1
# %bb.2: # %bb2
.pseudoprobe 837061429793323041 6 2 0
callq foo
.pseudoprobe 837061429793323041 3 0 0
.pseudoprobe 837061429793323041 4 0 0
popq %rax
retq
.LBB1_1: # %bb1
.pseudoprobe 837061429793323041 5 1 0
callq *%rsi
.pseudoprobe 837061429793323041 2 0 0
.pseudoprobe 837061429793323041 4 0 0
popq %rax
retq
# -- End function
.section .pseudo_probe_desc,"",@progbits
.quad 6699318081062747564
.quad 72617220756
.byte 3
.ascii "foo"
.quad 837061429793323041
.quad 281547593931412
.byte 4
.ascii "foo2"
```

With inlining turned on, the assembly may look different around %bb2 with an inlined probe:

```
# %bb.2:                                # %bb2
.pseudoprobe    837061429793323041 3 0
.pseudoprobe    6699318081062747564 1 0 @ 837061429793323041:6
.pseudoprobe    837061429793323041 4 0
popq    %rax
retq
```

**Disassembling**

We have a disassembling tool (llvm-profgen) that can display disassembly alongside with pseudo probes. So far it only supports ELF executable file.

An example disassembly looks like:

```
00000000002011a0 <foo2>:
  2011a0: 50                    push   rax
  2011a1: 85 ff                 test   edi,edi
  [Probe]:  FUNC: foo2  Index: 1  Type: Block
  2011a3: 74 02                 je     2011a7 <foo2+0x7>
  [Probe]:  FUNC: foo2  Index: 3  Type: Block
  [Probe]:  FUNC: foo2  Index: 4  Type: Block
  [Probe]:  FUNC: foo   Index: 1  Type: Block  Inlined: @ foo2:6
  2011a5: 58                    pop    rax
  2011a6: c3                    ret
  [Probe]:  FUNC: foo2  Index: 2  Type: Block
  2011a7: bf 01 00 00 00        mov    edi,0x1
  [Probe]:  FUNC: foo2  Index: 5  Type: IndirectCall
  2011ac: ff d6                 call   rsi
  [Probe]:  FUNC: foo2  Index: 4  Type: Block
  2011ae: 58                    pop    rax
  2011af: c3                    ret
```

Reviewed By: wmi

Differential Revision: https://reviews.llvm.org/D91878
2020-12-10 09:50:08 -08:00
Scott Linder 19c56e11fa [MC] Fix ICE with non-newline terminated input
There is an explicit option for the lexer to support this, but we crash
when `-preserve-comments` is enabled because it checks for
`getTok().getString().empty()` to detect the case. This doesn't
work currently because the lexer reports this case as a string of length
1, containing a null byte.

Change the lexer to instead report this case via an empty string, as the
null terminator isn't logically a part of the textual input, and the
check for `.empty()` seems natural and obvious in the calling code.

Reviewed By: niravd

Differential Revision: https://reviews.llvm.org/D92681
2020-12-09 23:39:32 +00:00
Amy Huang 399bc48ecc [CodeView] Fix inline sites that are missing code offsets.
When an inline site has a starting code offset of 0, we sometimes
don't emit the starting offset.

Bug: https://bugs.llvm.org/show_bug.cgi?id=48377

Differential Revision: https://reviews.llvm.org/D92590
2020-12-07 13:01:53 -08:00
Derek Schuff 0a391060f1 [WebAssembly] Add Object and ObjectWriter support for wasm COMDAT sections
Allow sections to be placed into COMDAT groups, in addtion to functions and data
segments.

Also make section symbols unnamed, which allows sections with identical names
(section names are independent of their section symbols, but previously we
gave the symbols the same name as their sections, which results in collisions
when sections are identically-named).

Differential Revision: https://reviews.llvm.org/D92691
2020-12-07 12:12:44 -08:00
Andy Wingo d823cc7cad [WebAssembly][MC] Fix placement of table section
The table section goes after functions.

Differential Revision: https://reviews.llvm.org/D92323
2020-12-07 16:17:32 +01:00
Fangrui Song 9c53b2adc8 [MC] Delete unused declarations
Notes:

* llvm::createAsmStreamer: it has been moved to TargetRegistry.h
* (anon ns)::WasmObjectWriter::updateCustomSectionRelocations: remnant of D46335
* COFFAsmParser::ParseSEHRegisterNumber: remnant of D66625
* llvm::CodeViewContext::isValidCVFileNumber: accidentally added by r279847
2020-12-06 15:36:39 -08:00
Scott Linder d55d6806ad [MC] Consume EndOfStatement in .cfi_{sections,endproc}
Previously these directives were always interpreted as having an extra
blank line after them.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D92612
2020-12-04 22:30:29 +00:00
jasonliu 2c63e7604c [XCOFF][AIX] Alternative path in EHStreamer for platforms do not have uleb128 support
Summary:
Not all system assembler supports `.uleb128 label2 - label1` form.
When the target do not support this form, we have to take
alternative manual calculation to get the offsets from them.

Reviewed By: hubert.reinterpretcast

Diffierential Revision: https://reviews.llvm.org/D92058
2020-12-02 20:03:15 +00:00
jasonliu a65d8c5d72 [XCOFF][AIX] Generate LSDA data and compact unwind section on AIX
Summary:
AIX uses the existing EH infrastructure in clang and llvm.
The major differences would be
1. AIX do not have CFI instructions.
2. AIX uses a new personality routine, named __xlcxx_personality_v1.
   It doesn't use the GCC personality rountine, because the
   interoperability is not there yet on AIX.
3. AIX do not use eh_frame sections. Instead, it would use a eh_info
section (compat unwind section) to store the information about
personality routine and LSDA data address.

Reviewed By: daltenty, hubert.reinterpretcast

Differential Revision: https://reviews.llvm.org/D91455
2020-12-02 18:42:44 +00:00
Eric Astor c64037b784 [ms] [llvm-ml] Support command-line defines
Enable command-line defines as textmacros

Reviewed By: thakis

Differential Revision: https://reviews.llvm.org/D90059
2020-12-01 18:06:05 -05:00
Rahman Lavaee e0bf234930 Let .llvm_bb_addr_map section use the same unique id as its associated .text section.
Currently, `llvm_bb_addr_map` sections are generated per section names because we use
the `LinkedToSymbol` argument of getELFSection. This will cause the address map tables of functions
grouped into the same section when `-function-sections=true -unique-section-names=false` which is not
the intended behaviour. This patch lets the unique id of every `.text` section propagate to the associated
`.llvm_bb_addr_map` section.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D92113
2020-12-01 09:21:00 -08:00
Fangrui Song f0659c0673 [X86] Support modifier @PLTOFF for R_X86_64_PLTOFF64
`gcc -mcmodel=large` can emit @PLTOFF.

Reviewed By: grimar

Differential Revision: https://reviews.llvm.org/D92294
2020-12-01 08:39:01 -08:00
Eric Astor abef659a45 [ms] [llvm-ml] Implement the statement expansion operator
If prefaced with a %, expand text macros and macro functions in any statement.

Also, prevent expanding text macros in the message of an ECHO directive unless expanded explicitly by the statement expansion operator.

Reviewed By: thakis

Differential Revision: https://reviews.llvm.org/D89740
2020-11-30 14:33:24 -05:00
Fangrui Song e6c1777685 [MC] Copy visibility for .symver created symbols 2020-11-29 16:51:48 -08:00
Fangrui Song 668da8c361 [MC] Set the unique id of .stack_sizes to the associated .text section's
Similar to D92113. Currently `clang -fstack-size-section -fno-unique-section-names`
sets the linked-to symbol to the first `.text`, which is:

* incorrect for COMDAT sections
* inferior for non-COMDAT sections in -ffunction-sections mode (poor --gc-sections: .stack_sizes cannot be separately discarded)

Note, if the section symbol can be referenced in more places (if the
function begin symbol does not apply), we probably should consider
defining a different BeginSymbol for sections with ",unique" linkage.

Reviewed By: grimar, jhenderson

Differential Revision: https://reviews.llvm.org/D92151
2020-11-26 09:13:09 -08:00
Eric Astor 35828b84a5 [ms] [llvm-ml] Implement the expression expansion operator
In text-item contexts, %expr expands to a string containing the results of evaluating `expr`.

Reviewed By: thakis

Differential Revision: https://reviews.llvm.org/D89736
2020-11-25 16:11:00 -05:00
Andy Wingo feac819e50 [MC][WebAssembly] Only emit indirect function table import if needed
The indirect function table, synthesized by the linker, is needed if and
only if there are TABLE_INDEX relocs.

Differential Revision: https://reviews.llvm.org/D91637
2020-11-25 08:38:43 -08:00
Andy Wingo 1933c9d41a [WebAssembly] Factor out WasmTableType in binary format
This commit factors out a WasmTableType definition from WasmTable, as is
the case for WasmGlobal and other data types.  Also add support for
extracting the SymbolName for a table from the linking section's symbol
table.

Differential Revision: https://reviews.llvm.org/D91849
2020-11-25 08:00:08 -08:00
Martin Storsjö 6f792041a5 Reapply "[CodeGen] [WinException] Only produce handler data at the end of the function if needed"
This reapplies 36c64af9d7 in updated
form.

Emit the xdata for each function at .seh_endproc. This keeps the
exact same output header order for most code generated by the LLVM
CodeGen layer. (Sections still change order for code built from
assembly where functions lack an explicit .seh_handlerdata
directive, and functions with chained unwind info.)

The practical effect should be that assembly output lacks
superfluous ".seh_handlerdata; .text" pairs at the end of functions
that don't handle exceptions, which allows such functions to use
the AArch64 packed unwind format again.

Differential Revision: https://reviews.llvm.org/D87448
2020-11-23 23:17:03 +02:00
Eric Astor 1e41e22323 [ms] [llvm-ml] Support purging macro definitions
Support MASM's PURGE directive.

Reviewed By: thakis

Differential Revision: https://reviews.llvm.org/D89735
2020-11-23 15:03:13 -05:00
Eric Astor 454f32e4d5 [ms] [llvm-ml] Support macro function invocations in expressions
Accept macro function definitions, and apply them when invoked in operand position.

Reviewed By: thakis

Differential Revision: https://reviews.llvm.org/D89734
2020-11-23 14:16:28 -05:00
Duncan P. N. Exon Smith 5abf76fbe3 ADT: Add assertions to SmallVector::insert, etc., for reference invalidation
2c196bbc6b asserted that
`SmallVector::push_back` doesn't invalidate the parameter when it needs
to grow. Do the same for `resize`, `append`, `assign`, `insert`, and
`emplace_back`.

Differential Revision: https://reviews.llvm.org/D91744
2020-11-18 17:36:28 -08:00
Fangrui Song 96d40df71e MCExpr::evaluateAsRelocatableImpl : allow evaluation of non-VK_None MCSymbolRefExpr when MCAsmLayout is available
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=4acf8c78e659833be8be047ba2f8561386a11d4b
(1994) introduced this behavior:
if a fixup symbol is equated to an expression with an undefined symbol, convert
the fixup to be against the target symbol. glibc relies on this behavior to perform
assembly level indirection

```
asm("memcpy = __GI_memcpy"); // from sysdeps/generic/symbol-hacks.h

...
  // call memcpy@PLT
  // The relocation references __GI_memcpy in GNU as, but memcpy in MC (without the patch)
  memcpy (...);
```

(1) It complements `extern __typeof(memcpy) memcpy asm("__GI_memcpy");` The frontend asm label does not redirect synthesized memcpy in the middle-end. (See D88712 for details)
(2) `asm("memcpy = __GI_memcpy");` is in every translation unit, but the memcpy declaration may not be visible in the translation unit where memcpy is synthesized.

MC already redirects `memcpy = __GI_memcpy; call memcpy` but not `memcpy = __GI_memcpy; call memcpy@plt`.
This patch fixes the latter by allowing MCExpr::evaluateAsRelocatableImpl to
evaluate a non-VK_None MCSymbolRefExpr, which is only done after the layout is available.

GNU as allows `memcpy = __GI_memcpy+1; call memcpy@PLT` which seems nonsensical, so we don't allow it.

`MC/PowerPC/pr38945.s` `NUMBER = 0x6ffffff9; cmpwi 8,NUMBER@l` requires the
`symbol@l` form in AsmMatcher, so evaluation needs to be deferred. This is the
place whether future simplification may be possible.

Note, if we suppress the VM_None evaluation when MCAsmLayout is nullptr, we may
lose the `invalid reassignment of non-absolute variable` diagnostic
(`ARM/thumb_set-diagnostics.s` and `MC/AsmParser/variables-invalid.s`).
We know that this diagnostic is troublesome in some cases
(https://github.com/ClangBuiltLinux/linux/issues/1008), so we can consider
making simplification in the future.

Reviewed By: jyknight

Differential Revision: https://reviews.llvm.org/D88625
2020-11-18 13:52:33 -08:00
Andrew Paverd 0139c8af8d [CFGuard] Add address-taken IAT tables and delay-load support
This patch adds support for creating Guard Address-Taken IAT Entry Tables (.giats$y sections) in object files, matching the behavior of MSVC. These contain lists of address-taken imported functions, which are used by the linker to create the final GIATS table.
Additionally, if any DLLs are delay-loaded, the linker must look through the .giats tables and add the respective load thunks of address-taken imports to the GFIDS table, as these are also valid call targets.

Reviewed By: rnk

Differential Revision: https://reviews.llvm.org/D87544
2020-11-17 18:24:45 -08:00
Andy Wingo b90228e411 [WebAssembly][MC] Remove useless overrides in MCWasmStreamer
Differential Revision: https://reviews.llvm.org/D91604
2020-11-17 07:09:49 -08:00
Florian Hahn a9adb62a64
[AsmPrinter] Use getMnemonic for instruction-mix remark.
This patch uses the new `getMnemonic` helper from D90039
to display mnemonics instead of the internal opcodes.

The main motivation behind using the mnemonics is that they
are more user-friendly and more directly related to the assembly
the users will be presented.

Reviewed By: paquette

Differential Revision: https://reviews.llvm.org/D90040
2020-11-17 12:12:47 +00:00
Fangrui Song fac0622ae0 ELFAsmParser: Remove non-SHF_ALLOC or non-executable sections' line info/address ranges contribution for -g
I filed the issue https://sourceware.org/bugzilla/show_bug.cgi?id=26850 ,
which was acknowledged and fixed in GNU binutils 2.36

This patch adds the similar behavior to MC.

Reviewed By: #debug-info, dblaikie

Differential Revision: https://reviews.llvm.org/D91505
2020-11-16 20:02:25 -08:00
Wouter van Oortmerssen 16f02431dc [WebAssembly] Added R_WASM_FUNCTION_OFFSET_I64 for use with DWARF DW_AT_low_pc
Needed for wasm64, see discussion in https://reviews.llvm.org/D91203

Differential Revision: https://reviews.llvm.org/D91395
2020-11-13 09:32:31 -08:00
Sam Clegg a28a466210 [WebAssembly] Add new relocation type for TLS data symbols
These relocations represent offsets from the __tls_base symbol.

Previously we were just using normal MEMORY_ADDR relocations and relying
on the linker to select a segment-offset rather and absolute value in
Symbol::getVirtualAddress().  Using an explicit relocation type allows
allow us to clearly distinguish absolute from relative relocations based
on the relocation information alone.

One place this is useful is being able to reject absolute relocation in
the PIC case, but still accept TLS relocations.

Differential Revision: https://reviews.llvm.org/D91276
2020-11-13 07:59:29 -08:00
Sam Clegg b646e8b154 [lld][WebAssembly] Add test for TLS BSS data. NFC.
Differential Revision: https://reviews.llvm.org/D91231
2020-11-13 07:52:18 -08:00
serge-sans-paille 9218ff50f9 llvmbuildectomy - replace llvm-build by plain cmake
No longer rely on an external tool to build the llvm component layout.

Instead, leverage the existing `add_llvm_componentlibrary` cmake function and
introduce `add_llvm_component_group` to accurately describe component behavior.

These function store extra properties in the created targets. These properties
are processed once all components are defined to resolve library dependencies
and produce the header expected by llvm-config.

Differential Revision: https://reviews.llvm.org/D90848
2020-11-13 10:35:24 +01:00