RPCS3/llvm-mirror
1
0
Fork 0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2024-10-19 11:02:59 +02:00
Code Issues Projects Releases Wiki Activity
1471de1de2
llvm-mirror/lib/MC/MCObjectFileInfo.cpp
Hongtao Yu 85e4f6f241 [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

1070 lines
44 KiB
C++
Raw Blame History

//===-- MCObjectFileInfo.cpp - Object File Information --------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "llvm/MC/MCObjectFileInfo.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/Triple.h"
#include "llvm/BinaryFormat/COFF.h"
#include "llvm/BinaryFormat/ELF.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCSection.h"
#include "llvm/MC/MCSectionCOFF.h"
#include "llvm/MC/MCSectionELF.h"
#include "llvm/MC/MCSectionMachO.h"
#include "llvm/MC/MCSectionWasm.h"
#include "llvm/MC/MCSectionXCOFF.h"
using namespace llvm;
static bool useCompactUnwind(const Triple &T) {
// Only on darwin.
if (!T.isOSDarwin())
return false;
// aarch64 always has it.
if (T.getArch() == Triple::aarch64 || T.getArch() == Triple::aarch64_32)
return true;
// armv7k always has it.
if (T.isWatchABI())
return true;
// Use it on newer version of OS X.
if (T.isMacOSX() && !T.isMacOSXVersionLT(10, 6))
return true;
// And the iOS simulator.
if (T.isiOS() && T.isX86())
return true;
return false;
}
void MCObjectFileInfo::initMachOMCObjectFileInfo(const Triple &T) {
// MachO
SupportsWeakOmittedEHFrame = false;
EHFrameSection = Ctx->getMachOSection(
"__TEXT", "__eh_frame",
MachO::S_COALESCED | MachO::S_ATTR_NO_TOC |
MachO::S_ATTR_STRIP_STATIC_SYMS | MachO::S_ATTR_LIVE_SUPPORT,
SectionKind::getReadOnly());
if (T.isOSDarwin() &&
(T.getArch() == Triple::aarch64 || T.getArch() == Triple::aarch64_32))
SupportsCompactUnwindWithoutEHFrame = true;
if (T.isWatchABI())
OmitDwarfIfHaveCompactUnwind = true;
FDECFIEncoding = dwarf::DW_EH_PE_pcrel;
// .comm doesn't support alignment before Leopard.
if (T.isMacOSX() && T.isMacOSXVersionLT(10, 5))
CommDirectiveSupportsAlignment = false;
TextSection // .text
= Ctx->getMachOSection("__TEXT", "__text",
MachO::S_ATTR_PURE_INSTRUCTIONS,
SectionKind::getText());
DataSection // .data
= Ctx->getMachOSection("__DATA", "__data", 0, SectionKind::getData());
// BSSSection might not be expected initialized on msvc.
BSSSection = nullptr;
TLSDataSection // .tdata
= Ctx->getMachOSection("__DATA", "__thread_data",
MachO::S_THREAD_LOCAL_REGULAR,
SectionKind::getData());
TLSBSSSection // .tbss
= Ctx->getMachOSection("__DATA", "__thread_bss",
MachO::S_THREAD_LOCAL_ZEROFILL,
SectionKind::getThreadBSS());
// TODO: Verify datarel below.
TLSTLVSection // .tlv
= Ctx->getMachOSection("__DATA", "__thread_vars",
MachO::S_THREAD_LOCAL_VARIABLES,
SectionKind::getData());
TLSThreadInitSection = Ctx->getMachOSection(
"__DATA", "__thread_init", MachO::S_THREAD_LOCAL_INIT_FUNCTION_POINTERS,
SectionKind::getData());
CStringSection // .cstring
= Ctx->getMachOSection("__TEXT", "__cstring",
MachO::S_CSTRING_LITERALS,
SectionKind::getMergeable1ByteCString());
UStringSection
= Ctx->getMachOSection("__TEXT","__ustring", 0,
SectionKind::getMergeable2ByteCString());
FourByteConstantSection // .literal4
= Ctx->getMachOSection("__TEXT", "__literal4",
MachO::S_4BYTE_LITERALS,
SectionKind::getMergeableConst4());
EightByteConstantSection // .literal8
= Ctx->getMachOSection("__TEXT", "__literal8",
MachO::S_8BYTE_LITERALS,
SectionKind::getMergeableConst8());
SixteenByteConstantSection // .literal16
= Ctx->getMachOSection("__TEXT", "__literal16",
MachO::S_16BYTE_LITERALS,
SectionKind::getMergeableConst16());
ReadOnlySection // .const
= Ctx->getMachOSection("__TEXT", "__const", 0,
SectionKind::getReadOnly());
// If the target is not powerpc, map the coal sections to the non-coal
// sections.
//
// "__TEXT/__textcoal_nt" => section "__TEXT/__text"
// "__TEXT/__const_coal" => section "__TEXT/__const"
// "__DATA/__datacoal_nt" => section "__DATA/__data"
Triple::ArchType ArchTy = T.getArch();
ConstDataSection // .const_data
= Ctx->getMachOSection("__DATA", "__const", 0,
SectionKind::getReadOnlyWithRel());
if (ArchTy == Triple::ppc || ArchTy == Triple::ppc64) {
TextCoalSection
= Ctx->getMachOSection("__TEXT", "__textcoal_nt",
MachO::S_COALESCED |
MachO::S_ATTR_PURE_INSTRUCTIONS,
SectionKind::getText());
ConstTextCoalSection
= Ctx->getMachOSection("__TEXT", "__const_coal",
MachO::S_COALESCED,
SectionKind::getReadOnly());
DataCoalSection = Ctx->getMachOSection(
"__DATA", "__datacoal_nt", MachO::S_COALESCED, SectionKind::getData());
ConstDataCoalSection = DataCoalSection;
} else {
TextCoalSection = TextSection;
ConstTextCoalSection = ReadOnlySection;
DataCoalSection = DataSection;
ConstDataCoalSection = ConstDataSection;
}
DataCommonSection
= Ctx->getMachOSection("__DATA","__common",
MachO::S_ZEROFILL,
SectionKind::getBSS());
DataBSSSection
= Ctx->getMachOSection("__DATA","__bss", MachO::S_ZEROFILL,
SectionKind::getBSS());
LazySymbolPointerSection
= Ctx->getMachOSection("__DATA", "__la_symbol_ptr",
MachO::S_LAZY_SYMBOL_POINTERS,
SectionKind::getMetadata());
NonLazySymbolPointerSection
= Ctx->getMachOSection("__DATA", "__nl_symbol_ptr",
MachO::S_NON_LAZY_SYMBOL_POINTERS,
SectionKind::getMetadata());
ThreadLocalPointerSection
= Ctx->getMachOSection("__DATA", "__thread_ptr",
MachO::S_THREAD_LOCAL_VARIABLE_POINTERS,
SectionKind::getMetadata());
// Exception Handling.
LSDASection = Ctx->getMachOSection("__TEXT", "__gcc_except_tab", 0,
SectionKind::getReadOnlyWithRel());
COFFDebugSymbolsSection = nullptr;
COFFDebugTypesSection = nullptr;
COFFGlobalTypeHashesSection = nullptr;
if (useCompactUnwind(T)) {
CompactUnwindSection =
Ctx->getMachOSection("__LD", "__compact_unwind", MachO::S_ATTR_DEBUG,
SectionKind::getReadOnly());
if (T.isX86())
CompactUnwindDwarfEHFrameOnly = 0x04000000; // UNWIND_X86_64_MODE_DWARF
else if (T.getArch() == Triple::aarch64 || T.getArch() == Triple::aarch64_32)
CompactUnwindDwarfEHFrameOnly = 0x03000000; // UNWIND_ARM64_MODE_DWARF
else if (T.getArch() == Triple::arm || T.getArch() == Triple::thumb)
CompactUnwindDwarfEHFrameOnly = 0x04000000; // UNWIND_ARM_MODE_DWARF
}
// Debug Information.
DwarfDebugNamesSection =
Ctx->getMachOSection("__DWARF", "__debug_names", MachO::S_ATTR_DEBUG,
SectionKind::getMetadata(), "debug_names_begin");
DwarfAccelNamesSection =
Ctx->getMachOSection("__DWARF", "__apple_names", MachO::S_ATTR_DEBUG,
SectionKind::getMetadata(), "names_begin");
DwarfAccelObjCSection =
Ctx->getMachOSection("__DWARF", "__apple_objc", MachO::S_ATTR_DEBUG,
SectionKind::getMetadata(), "objc_begin");
// 16 character section limit...
DwarfAccelNamespaceSection =
Ctx->getMachOSection("__DWARF", "__apple_namespac", MachO::S_ATTR_DEBUG,
SectionKind::getMetadata(), "namespac_begin");
DwarfAccelTypesSection =
Ctx->getMachOSection("__DWARF", "__apple_types", MachO::S_ATTR_DEBUG,
SectionKind::getMetadata(), "types_begin");
DwarfSwiftASTSection =
Ctx->getMachOSection("__DWARF", "__swift_ast", MachO::S_ATTR_DEBUG,
SectionKind::getMetadata());
DwarfAbbrevSection =
Ctx->getMachOSection("__DWARF", "__debug_abbrev", MachO::S_ATTR_DEBUG,
SectionKind::getMetadata(), "section_abbrev");
DwarfInfoSection =
Ctx->getMachOSection("__DWARF", "__debug_info", MachO::S_ATTR_DEBUG,
SectionKind::getMetadata(), "section_info");
DwarfLineSection =
Ctx->getMachOSection("__DWARF", "__debug_line", MachO::S_ATTR_DEBUG,
SectionKind::getMetadata(), "section_line");
DwarfLineStrSection =
Ctx->getMachOSection("__DWARF", "__debug_line_str", MachO::S_ATTR_DEBUG,
SectionKind::getMetadata(), "section_line_str");
DwarfFrameSection =
Ctx->getMachOSection("__DWARF", "__debug_frame", MachO::S_ATTR_DEBUG,
SectionKind::getMetadata());
DwarfPubNamesSection =
Ctx->getMachOSection("__DWARF", "__debug_pubnames", MachO::S_ATTR_DEBUG,
SectionKind::getMetadata());
DwarfPubTypesSection =
Ctx->getMachOSection("__DWARF", "__debug_pubtypes", MachO::S_ATTR_DEBUG,
SectionKind::getMetadata());
DwarfGnuPubNamesSection =
Ctx->getMachOSection("__DWARF", "__debug_gnu_pubn", MachO::S_ATTR_DEBUG,
SectionKind::getMetadata());
DwarfGnuPubTypesSection =
Ctx->getMachOSection("__DWARF", "__debug_gnu_pubt", MachO::S_ATTR_DEBUG,
SectionKind::getMetadata());
DwarfStrSection =
Ctx->getMachOSection("__DWARF", "__debug_str", MachO::S_ATTR_DEBUG,
SectionKind::getMetadata(), "info_string");
DwarfStrOffSection =
Ctx->getMachOSection("__DWARF", "__debug_str_offs", MachO::S_ATTR_DEBUG,
SectionKind::getMetadata(), "section_str_off");
DwarfAddrSection =
Ctx->getMachOSection("__DWARF", "__debug_addr", MachO::S_ATTR_DEBUG,
SectionKind::getMetadata(), "section_info");
DwarfLocSection =
Ctx->getMachOSection("__DWARF", "__debug_loc", MachO::S_ATTR_DEBUG,
SectionKind::getMetadata(), "section_debug_loc");
DwarfLoclistsSection =
Ctx->getMachOSection("__DWARF", "__debug_loclists", MachO::S_ATTR_DEBUG,
SectionKind::getMetadata(), "section_debug_loc");
DwarfARangesSection =
Ctx->getMachOSection("__DWARF", "__debug_aranges", MachO::S_ATTR_DEBUG,
SectionKind::getMetadata());
DwarfRangesSection =
Ctx->getMachOSection("__DWARF", "__debug_ranges", MachO::S_ATTR_DEBUG,
SectionKind::getMetadata(), "debug_range");
DwarfRnglistsSection =
Ctx->getMachOSection("__DWARF", "__debug_rnglists", MachO::S_ATTR_DEBUG,
SectionKind::getMetadata(), "debug_range");
DwarfMacinfoSection =
Ctx->getMachOSection("__DWARF", "__debug_macinfo", MachO::S_ATTR_DEBUG,
SectionKind::getMetadata(), "debug_macinfo");
DwarfMacroSection =
Ctx->getMachOSection("__DWARF", "__debug_macro", MachO::S_ATTR_DEBUG,
SectionKind::getMetadata(), "debug_macro");
DwarfDebugInlineSection =
Ctx->getMachOSection("__DWARF", "__debug_inlined", MachO::S_ATTR_DEBUG,
SectionKind::getMetadata());
DwarfCUIndexSection =
Ctx->getMachOSection("__DWARF", "__debug_cu_index", MachO::S_ATTR_DEBUG,
SectionKind::getMetadata());
DwarfTUIndexSection =
Ctx->getMachOSection("__DWARF", "__debug_tu_index", MachO::S_ATTR_DEBUG,
SectionKind::getMetadata());
StackMapSection = Ctx->getMachOSection("__LLVM_STACKMAPS", "__llvm_stackmaps",
0, SectionKind::getMetadata());
FaultMapSection = Ctx->getMachOSection("__LLVM_FAULTMAPS", "__llvm_faultmaps",
0, SectionKind::getMetadata());
RemarksSection = Ctx->getMachOSection(
"__LLVM", "__remarks", MachO::S_ATTR_DEBUG, SectionKind::getMetadata());
TLSExtraDataSection = TLSTLVSection;
}
void MCObjectFileInfo::initELFMCObjectFileInfo(const Triple &T, bool Large) {
switch (T.getArch()) {
case Triple::mips:
case Triple::mipsel:
case Triple::mips64:
case Triple::mips64el:
// We cannot use DW_EH_PE_sdata8 for the large PositionIndependent case
// since there is no R_MIPS_PC64 relocation (only a 32-bit version).
if (PositionIndependent && !Large)
FDECFIEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
else
FDECFIEncoding = Ctx->getAsmInfo()->getCodePointerSize() == 4
? dwarf::DW_EH_PE_sdata4
: dwarf::DW_EH_PE_sdata8;
break;
case Triple::ppc64:
case Triple::ppc64le:
case Triple::aarch64:
case Triple::aarch64_be:
case Triple::x86_64:
FDECFIEncoding = dwarf::DW_EH_PE_pcrel |
(Large ? dwarf::DW_EH_PE_sdata8 : dwarf::DW_EH_PE_sdata4);
break;
case Triple::bpfel:
case Triple::bpfeb:
FDECFIEncoding = dwarf::DW_EH_PE_sdata8;
break;
case Triple::hexagon:
FDECFIEncoding =
PositionIndependent ? dwarf::DW_EH_PE_pcrel : dwarf::DW_EH_PE_absptr;
break;
default:
FDECFIEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
break;
}
unsigned EHSectionType = T.getArch() == Triple::x86_64
? ELF::SHT_X86_64_UNWIND
: ELF::SHT_PROGBITS;
// Solaris requires different flags for .eh_frame to seemingly every other
// platform.
unsigned EHSectionFlags = ELF::SHF_ALLOC;
if (T.isOSSolaris() && T.getArch() != Triple::x86_64)
EHSectionFlags |= ELF::SHF_WRITE;
// ELF
BSSSection = Ctx->getELFSection(".bss", ELF::SHT_NOBITS,
ELF::SHF_WRITE | ELF::SHF_ALLOC);
TextSection = Ctx->getELFSection(".text", ELF::SHT_PROGBITS,
ELF::SHF_EXECINSTR | ELF::SHF_ALLOC);
DataSection = Ctx->getELFSection(".data", ELF::SHT_PROGBITS,
ELF::SHF_WRITE | ELF::SHF_ALLOC);
ReadOnlySection =
Ctx->getELFSection(".rodata", ELF::SHT_PROGBITS, ELF::SHF_ALLOC);
TLSDataSection =
Ctx->getELFSection(".tdata", ELF::SHT_PROGBITS,
ELF::SHF_ALLOC | ELF::SHF_TLS | ELF::SHF_WRITE);
TLSBSSSection = Ctx->getELFSection(
".tbss", ELF::SHT_NOBITS, ELF::SHF_ALLOC | ELF::SHF_TLS | ELF::SHF_WRITE);
DataRelROSection = Ctx->getELFSection(".data.rel.ro", ELF::SHT_PROGBITS,
ELF::SHF_ALLOC | ELF::SHF_WRITE);
MergeableConst4Section =
Ctx->getELFSection(".rodata.cst4", ELF::SHT_PROGBITS,
ELF::SHF_ALLOC | ELF::SHF_MERGE, 4, "");
MergeableConst8Section =
Ctx->getELFSection(".rodata.cst8", ELF::SHT_PROGBITS,
ELF::SHF_ALLOC | ELF::SHF_MERGE, 8, "");
MergeableConst16Section =
Ctx->getELFSection(".rodata.cst16", ELF::SHT_PROGBITS,
ELF::SHF_ALLOC | ELF::SHF_MERGE, 16, "");
MergeableConst32Section =
Ctx->getELFSection(".rodata.cst32", ELF::SHT_PROGBITS,
ELF::SHF_ALLOC | ELF::SHF_MERGE, 32, "");
// Exception Handling Sections.
// FIXME: We're emitting LSDA info into a readonly section on ELF, even though
// it contains relocatable pointers. In PIC mode, this is probably a big
// runtime hit for C++ apps. Either the contents of the LSDA need to be
// adjusted or this should be a data section.
LSDASection = Ctx->getELFSection(".gcc_except_table", ELF::SHT_PROGBITS,
ELF::SHF_ALLOC);
COFFDebugSymbolsSection = nullptr;
COFFDebugTypesSection = nullptr;
unsigned DebugSecType = ELF::SHT_PROGBITS;
// MIPS .debug_* sections should have SHT_MIPS_DWARF section type
// to distinguish among sections contain DWARF and ECOFF debug formats.
// Sections with ECOFF debug format are obsoleted and marked by SHT_PROGBITS.
if (T.isMIPS())
DebugSecType = ELF::SHT_MIPS_DWARF;
// Debug Info Sections.
DwarfAbbrevSection =
Ctx->getELFSection(".debug_abbrev", DebugSecType, 0);
DwarfInfoSection = Ctx->getELFSection(".debug_info", DebugSecType, 0);
DwarfLineSection = Ctx->getELFSection(".debug_line", DebugSecType, 0);
DwarfLineStrSection =
Ctx->getELFSection(".debug_line_str", DebugSecType,
ELF::SHF_MERGE | ELF::SHF_STRINGS, 1, "");
DwarfFrameSection = Ctx->getELFSection(".debug_frame", DebugSecType, 0);
DwarfPubNamesSection =
Ctx->getELFSection(".debug_pubnames", DebugSecType, 0);
DwarfPubTypesSection =
Ctx->getELFSection(".debug_pubtypes", DebugSecType, 0);
DwarfGnuPubNamesSection =
Ctx->getELFSection(".debug_gnu_pubnames", DebugSecType, 0);
DwarfGnuPubTypesSection =
Ctx->getELFSection(".debug_gnu_pubtypes", DebugSecType, 0);
DwarfStrSection =
Ctx->getELFSection(".debug_str", DebugSecType,
ELF::SHF_MERGE | ELF::SHF_STRINGS, 1, "");
DwarfLocSection = Ctx->getELFSection(".debug_loc", DebugSecType, 0);
DwarfARangesSection =
Ctx->getELFSection(".debug_aranges", DebugSecType, 0);
DwarfRangesSection =
Ctx->getELFSection(".debug_ranges", DebugSecType, 0);
DwarfMacinfoSection =
Ctx->getELFSection(".debug_macinfo", DebugSecType, 0);
DwarfMacroSection = Ctx->getELFSection(".debug_macro", DebugSecType, 0);
// DWARF5 Experimental Debug Info
// Accelerator Tables
DwarfDebugNamesSection =
Ctx->getELFSection(".debug_names", ELF::SHT_PROGBITS, 0);
DwarfAccelNamesSection =
Ctx->getELFSection(".apple_names", ELF::SHT_PROGBITS, 0);
DwarfAccelObjCSection =
Ctx->getELFSection(".apple_objc", ELF::SHT_PROGBITS, 0);
DwarfAccelNamespaceSection =
Ctx->getELFSection(".apple_namespaces", ELF::SHT_PROGBITS, 0);
DwarfAccelTypesSection =
Ctx->getELFSection(".apple_types", ELF::SHT_PROGBITS, 0);
// String Offset and Address Sections
DwarfStrOffSection =
Ctx->getELFSection(".debug_str_offsets", DebugSecType, 0);
DwarfAddrSection = Ctx->getELFSection(".debug_addr", DebugSecType, 0);
DwarfRnglistsSection = Ctx->getELFSection(".debug_rnglists", DebugSecType, 0);
DwarfLoclistsSection = Ctx->getELFSection(".debug_loclists", DebugSecType, 0);
// Fission Sections
DwarfInfoDWOSection =
Ctx->getELFSection(".debug_info.dwo", DebugSecType, ELF::SHF_EXCLUDE);
DwarfTypesDWOSection =
Ctx->getELFSection(".debug_types.dwo", DebugSecType, ELF::SHF_EXCLUDE);
DwarfAbbrevDWOSection =
Ctx->getELFSection(".debug_abbrev.dwo", DebugSecType, ELF::SHF_EXCLUDE);
DwarfStrDWOSection = Ctx->getELFSection(
".debug_str.dwo", DebugSecType,
ELF::SHF_MERGE | ELF::SHF_STRINGS | ELF::SHF_EXCLUDE, 1, "");
DwarfLineDWOSection =
Ctx->getELFSection(".debug_line.dwo", DebugSecType, ELF::SHF_EXCLUDE);
DwarfLocDWOSection =
Ctx->getELFSection(".debug_loc.dwo", DebugSecType, ELF::SHF_EXCLUDE);
DwarfStrOffDWOSection = Ctx->getELFSection(".debug_str_offsets.dwo",
DebugSecType, ELF::SHF_EXCLUDE);
DwarfRnglistsDWOSection =
Ctx->getELFSection(".debug_rnglists.dwo", DebugSecType, ELF::SHF_EXCLUDE);
DwarfMacinfoDWOSection =
Ctx->getELFSection(".debug_macinfo.dwo", DebugSecType, ELF::SHF_EXCLUDE);
DwarfMacroDWOSection =
Ctx->getELFSection(".debug_macro.dwo", DebugSecType, ELF::SHF_EXCLUDE);
DwarfLoclistsDWOSection =
Ctx->getELFSection(".debug_loclists.dwo", DebugSecType, ELF::SHF_EXCLUDE);
// DWP Sections
DwarfCUIndexSection =
Ctx->getELFSection(".debug_cu_index", DebugSecType, 0);
DwarfTUIndexSection =
Ctx->getELFSection(".debug_tu_index", DebugSecType, 0);
StackMapSection =
Ctx->getELFSection(".llvm_stackmaps", ELF::SHT_PROGBITS, ELF::SHF_ALLOC);
FaultMapSection =
Ctx->getELFSection(".llvm_faultmaps", ELF::SHT_PROGBITS, ELF::SHF_ALLOC);
EHFrameSection =
Ctx->getELFSection(".eh_frame", EHSectionType, EHSectionFlags);
StackSizesSection = Ctx->getELFSection(".stack_sizes", ELF::SHT_PROGBITS, 0);
PseudoProbeSection = Ctx->getELFSection(".pseudo_probe", DebugSecType, 0);
PseudoProbeDescSection =
Ctx->getELFSection(".pseudo_probe_desc", DebugSecType, 0);
}
void MCObjectFileInfo::initCOFFMCObjectFileInfo(const Triple &T) {
EHFrameSection =
Ctx->getCOFFSection(".eh_frame", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getData());
// Set the `IMAGE_SCN_MEM_16BIT` flag when compiling for thumb mode. This is
// used to indicate to the linker that the text segment contains thumb instructions
// and to set the ISA selection bit for calls accordingly.
const bool IsThumb = T.getArch() == Triple::thumb;
CommDirectiveSupportsAlignment = true;
// COFF
BSSSection = Ctx->getCOFFSection(
".bss", COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ | COFF::IMAGE_SCN_MEM_WRITE,
SectionKind::getBSS());
TextSection = Ctx->getCOFFSection(
".text",
(IsThumb ? COFF::IMAGE_SCN_MEM_16BIT : (COFF::SectionCharacteristics)0) |
COFF::IMAGE_SCN_CNT_CODE | COFF::IMAGE_SCN_MEM_EXECUTE |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getText());
DataSection = Ctx->getCOFFSection(
".data", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ |
COFF::IMAGE_SCN_MEM_WRITE,
SectionKind::getData());
ReadOnlySection = Ctx->getCOFFSection(
".rdata", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ,
SectionKind::getReadOnly());
if (T.getArch() == Triple::x86_64 || T.getArch() == Triple::aarch64) {
// On Windows 64 with SEH, the LSDA is emitted into the .xdata section
LSDASection = nullptr;
} else {
LSDASection = Ctx->getCOFFSection(".gcc_except_table",
COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getReadOnly());
}
// Debug info.
COFFDebugSymbolsSection =
Ctx->getCOFFSection(".debug$S", (COFF::IMAGE_SCN_MEM_DISCARDABLE |
COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ),
SectionKind::getMetadata());
COFFDebugTypesSection =
Ctx->getCOFFSection(".debug$T", (COFF::IMAGE_SCN_MEM_DISCARDABLE |
COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ),
SectionKind::getMetadata());
COFFGlobalTypeHashesSection = Ctx->getCOFFSection(
".debug$H",
(COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ),
SectionKind::getMetadata());
DwarfAbbrevSection = Ctx->getCOFFSection(
".debug_abbrev",
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata(), "section_abbrev");
DwarfInfoSection = Ctx->getCOFFSection(
".debug_info",
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata(), "section_info");
DwarfLineSection = Ctx->getCOFFSection(
".debug_line",
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata(), "section_line");
DwarfLineStrSection = Ctx->getCOFFSection(
".debug_line_str",
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata(), "section_line_str");
DwarfFrameSection = Ctx->getCOFFSection(
".debug_frame",
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata());
DwarfPubNamesSection = Ctx->getCOFFSection(
".debug_pubnames",
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata());
DwarfPubTypesSection = Ctx->getCOFFSection(
".debug_pubtypes",
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata());
DwarfGnuPubNamesSection = Ctx->getCOFFSection(
".debug_gnu_pubnames",
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata());
DwarfGnuPubTypesSection = Ctx->getCOFFSection(
".debug_gnu_pubtypes",
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata());
DwarfStrSection = Ctx->getCOFFSection(
".debug_str",
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata(), "info_string");
DwarfStrOffSection = Ctx->getCOFFSection(
".debug_str_offsets",
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata(), "section_str_off");
DwarfLocSection = Ctx->getCOFFSection(
".debug_loc",
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata(), "section_debug_loc");
DwarfLoclistsSection = Ctx->getCOFFSection(
".debug_loclists",
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata(), "section_debug_loclists");
DwarfARangesSection = Ctx->getCOFFSection(
".debug_aranges",
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata());
DwarfRangesSection = Ctx->getCOFFSection(
".debug_ranges",
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata(), "debug_range");
DwarfRnglistsSection = Ctx->getCOFFSection(
".debug_rnglists",
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata(), "debug_rnglists");
DwarfMacinfoSection = Ctx->getCOFFSection(
".debug_macinfo",
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata(), "debug_macinfo");
DwarfMacroSection = Ctx->getCOFFSection(
".debug_macro",
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata(), "debug_macro");
DwarfMacinfoDWOSection = Ctx->getCOFFSection(
".debug_macinfo.dwo",
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata(), "debug_macinfo.dwo");
DwarfMacroDWOSection = Ctx->getCOFFSection(
".debug_macro.dwo",
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata(), "debug_macro.dwo");
DwarfInfoDWOSection = Ctx->getCOFFSection(
".debug_info.dwo",
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata(), "section_info_dwo");
DwarfTypesDWOSection = Ctx->getCOFFSection(
".debug_types.dwo",
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata(), "section_types_dwo");
DwarfAbbrevDWOSection = Ctx->getCOFFSection(
".debug_abbrev.dwo",
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata(), "section_abbrev_dwo");
DwarfStrDWOSection = Ctx->getCOFFSection(
".debug_str.dwo",
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata(), "skel_string");
DwarfLineDWOSection = Ctx->getCOFFSection(
".debug_line.dwo",
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata());
DwarfLocDWOSection = Ctx->getCOFFSection(
".debug_loc.dwo",
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata(), "skel_loc");
DwarfStrOffDWOSection = Ctx->getCOFFSection(
".debug_str_offsets.dwo",
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata(), "section_str_off_dwo");
DwarfAddrSection = Ctx->getCOFFSection(
".debug_addr",
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata(), "addr_sec");
DwarfCUIndexSection = Ctx->getCOFFSection(
".debug_cu_index",
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata());
DwarfTUIndexSection = Ctx->getCOFFSection(
".debug_tu_index",
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata());
DwarfDebugNamesSection = Ctx->getCOFFSection(
".debug_names",
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata(), "debug_names_begin");
DwarfAccelNamesSection = Ctx->getCOFFSection(
".apple_names",
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata(), "names_begin");
DwarfAccelNamespaceSection = Ctx->getCOFFSection(
".apple_namespaces",
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata(), "namespac_begin");
DwarfAccelTypesSection = Ctx->getCOFFSection(
".apple_types",
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata(), "types_begin");
DwarfAccelObjCSection = Ctx->getCOFFSection(
".apple_objc",
COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata(), "objc_begin");
DrectveSection = Ctx->getCOFFSection(
".drectve", COFF::IMAGE_SCN_LNK_INFO | COFF::IMAGE_SCN_LNK_REMOVE,
SectionKind::getMetadata());
PDataSection = Ctx->getCOFFSection(
".pdata", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ,
SectionKind::getData());
XDataSection = Ctx->getCOFFSection(
".xdata", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ,
SectionKind::getData());
SXDataSection = Ctx->getCOFFSection(".sxdata", COFF::IMAGE_SCN_LNK_INFO,
SectionKind::getMetadata());
GFIDsSection = Ctx->getCOFFSection(".gfids$y",
COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata());
GIATsSection = Ctx->getCOFFSection(".giats$y",
COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata());
GLJMPSection = Ctx->getCOFFSection(".gljmp$y",
COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata());
TLSDataSection = Ctx->getCOFFSection(
".tls$", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ |
COFF::IMAGE_SCN_MEM_WRITE,
SectionKind::getData());
StackMapSection = Ctx->getCOFFSection(".llvm_stackmaps",
COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getReadOnly());
}
void MCObjectFileInfo::initWasmMCObjectFileInfo(const Triple &T) {
TextSection = Ctx->getWasmSection(".text", SectionKind::getText());
DataSection = Ctx->getWasmSection(".data", SectionKind::getData());
DwarfLineSection =
Ctx->getWasmSection(".debug_line", SectionKind::getMetadata());
DwarfLineStrSection =
Ctx->getWasmSection(".debug_line_str", SectionKind::getMetadata());
DwarfStrSection =
Ctx->getWasmSection(".debug_str", SectionKind::getMetadata());
DwarfLocSection =
Ctx->getWasmSection(".debug_loc", SectionKind::getMetadata());
DwarfAbbrevSection =
Ctx->getWasmSection(".debug_abbrev", SectionKind::getMetadata());
DwarfARangesSection = Ctx->getWasmSection(".debug_aranges", SectionKind::getMetadata());
DwarfRangesSection =
Ctx->getWasmSection(".debug_ranges", SectionKind::getMetadata());
DwarfMacinfoSection =
Ctx->getWasmSection(".debug_macinfo", SectionKind::getMetadata());
DwarfMacroSection =
Ctx->getWasmSection(".debug_macro", SectionKind::getMetadata());
DwarfCUIndexSection = Ctx->getWasmSection(".debug_cu_index", SectionKind::getMetadata());
DwarfTUIndexSection = Ctx->getWasmSection(".debug_tu_index", SectionKind::getMetadata());
DwarfInfoSection =
Ctx->getWasmSection(".debug_info", SectionKind::getMetadata());
DwarfFrameSection = Ctx->getWasmSection(".debug_frame", SectionKind::getMetadata());
DwarfPubNamesSection = Ctx->getWasmSection(".debug_pubnames", SectionKind::getMetadata());
DwarfPubTypesSection = Ctx->getWasmSection(".debug_pubtypes", SectionKind::getMetadata());
DwarfGnuPubNamesSection =
Ctx->getWasmSection(".debug_gnu_pubnames", SectionKind::getMetadata());
DwarfGnuPubTypesSection =
Ctx->getWasmSection(".debug_gnu_pubtypes", SectionKind::getMetadata());
DwarfDebugNamesSection =
Ctx->getWasmSection(".debug_names", SectionKind::getMetadata());
DwarfStrOffSection =
Ctx->getWasmSection(".debug_str_offsets", SectionKind::getMetadata());
DwarfAddrSection =
Ctx->getWasmSection(".debug_addr", SectionKind::getMetadata());
DwarfRnglistsSection =
Ctx->getWasmSection(".debug_rnglists", SectionKind::getMetadata());
DwarfLoclistsSection =
Ctx->getWasmSection(".debug_loclists", SectionKind::getMetadata());
// Fission Sections
DwarfInfoDWOSection =
Ctx->getWasmSection(".debug_info.dwo", SectionKind::getMetadata());
DwarfTypesDWOSection =
Ctx->getWasmSection(".debug_types.dwo", SectionKind::getMetadata());
DwarfAbbrevDWOSection =
Ctx->getWasmSection(".debug_abbrev.dwo", SectionKind::getMetadata());
DwarfStrDWOSection =
Ctx->getWasmSection(".debug_str.dwo", SectionKind::getMetadata());
DwarfLineDWOSection =
Ctx->getWasmSection(".debug_line.dwo", SectionKind::getMetadata());
DwarfLocDWOSection =
Ctx->getWasmSection(".debug_loc.dwo", SectionKind::getMetadata());
DwarfStrOffDWOSection =
Ctx->getWasmSection(".debug_str_offsets.dwo", SectionKind::getMetadata());
DwarfRnglistsDWOSection =
Ctx->getWasmSection(".debug_rnglists.dwo", SectionKind::getMetadata());
DwarfMacinfoDWOSection =
Ctx->getWasmSection(".debug_macinfo.dwo", SectionKind::getMetadata());
DwarfMacroDWOSection =
Ctx->getWasmSection(".debug_macro.dwo", SectionKind::getMetadata());
DwarfLoclistsDWOSection =
Ctx->getWasmSection(".debug_loclists.dwo", SectionKind::getMetadata());
// DWP Sections
DwarfCUIndexSection =
Ctx->getWasmSection(".debug_cu_index", SectionKind::getMetadata(), 0);
DwarfTUIndexSection =
Ctx->getWasmSection(".debug_tu_index", SectionKind::getMetadata(), 0);
// Wasm use data section for LSDA.
// TODO Consider putting each function's exception table in a separate
// section, as in -function-sections, to facilitate lld's --gc-section.
LSDASection = Ctx->getWasmSection(".rodata.gcc_except_table",
SectionKind::getReadOnlyWithRel());
// TODO: Define more sections.
}
void MCObjectFileInfo::initXCOFFMCObjectFileInfo(const Triple &T) {
// The default csect for program code. Functions without a specified section
// get placed into this csect. The choice of csect name is not a property of
// the ABI or object file format. For example, the XL compiler uses an unnamed
// csect for program code.
TextSection = Ctx->getXCOFFSection(
".text", XCOFF::StorageMappingClass::XMC_PR, XCOFF::XTY_SD,
SectionKind::getText(), /* MultiSymbolsAllowed*/ true);
DataSection = Ctx->getXCOFFSection(
".data", XCOFF::StorageMappingClass::XMC_RW, XCOFF::XTY_SD,
SectionKind::getData(), /* MultiSymbolsAllowed*/ true);
ReadOnlySection = Ctx->getXCOFFSection(
".rodata", XCOFF::StorageMappingClass::XMC_RO, XCOFF::XTY_SD,
SectionKind::getReadOnly(), /* MultiSymbolsAllowed*/ true);
TOCBaseSection =
Ctx->getXCOFFSection("TOC", XCOFF::StorageMappingClass::XMC_TC0,
XCOFF::XTY_SD, SectionKind::getData());
// The TOC-base always has 0 size, but 4 byte alignment.
TOCBaseSection->setAlignment(Align(4));
LSDASection = Ctx->getXCOFFSection(".gcc_except_table",
XCOFF::StorageMappingClass::XMC_RO,
XCOFF::XTY_SD, SectionKind::getReadOnly());
CompactUnwindSection =
Ctx->getXCOFFSection(".eh_info_table", XCOFF::StorageMappingClass::XMC_RW,
XCOFF::XTY_SD, SectionKind::getData());
// DWARF sections for XCOFF are not csects. They are special STYP_DWARF
// sections, and the individual DWARF sections are distinguished by their
// section subtype.
// TODO: Populate the DWARF sections appropriately.
DwarfAbbrevSection = nullptr; // SSUBTYP_DWABREV
DwarfInfoSection = nullptr; // SSUBTYP_DWINFO
DwarfLineSection = nullptr; // SSUBTYP_DWLINE
DwarfFrameSection = nullptr; // SSUBTYP_DWFRAME
DwarfPubNamesSection = nullptr; // SSUBTYP_DWPBNMS
DwarfPubTypesSection = nullptr; // SSUBTYP_DWPBTYP
DwarfStrSection = nullptr; // SSUBTYP_DWSTR
DwarfLocSection = nullptr; // SSUBTYP_DWLOC
DwarfARangesSection = nullptr; // SSUBTYP_DWARNGE
DwarfRangesSection = nullptr; // SSUBTYP_DWRNGES
DwarfMacinfoSection = nullptr; // SSUBTYP_DWMAC
}
void MCObjectFileInfo::InitMCObjectFileInfo(const Triple &TheTriple, bool PIC,
MCContext &ctx,
bool LargeCodeModel) {
PositionIndependent = PIC;
Ctx = &ctx;
// Common.
CommDirectiveSupportsAlignment = true;
SupportsWeakOmittedEHFrame = true;
SupportsCompactUnwindWithoutEHFrame = false;
OmitDwarfIfHaveCompactUnwind = false;
FDECFIEncoding = dwarf::DW_EH_PE_absptr;
CompactUnwindDwarfEHFrameOnly = 0;
EHFrameSection = nullptr; // Created on demand.
CompactUnwindSection = nullptr; // Used only by selected targets.
DwarfAccelNamesSection = nullptr; // Used only by selected targets.
DwarfAccelObjCSection = nullptr; // Used only by selected targets.
DwarfAccelNamespaceSection = nullptr; // Used only by selected targets.
DwarfAccelTypesSection = nullptr; // Used only by selected targets.
TT = TheTriple;
switch (TT.getObjectFormat()) {
case Triple::MachO:
Env = IsMachO;
initMachOMCObjectFileInfo(TT);
break;
case Triple::COFF:
if (!TT.isOSWindows())
report_fatal_error(
"Cannot initialize MC for non-Windows COFF object files.");
Env = IsCOFF;
initCOFFMCObjectFileInfo(TT);
break;
case Triple::ELF:
Env = IsELF;
initELFMCObjectFileInfo(TT, LargeCodeModel);
break;
case Triple::Wasm:
Env = IsWasm;
initWasmMCObjectFileInfo(TT);
break;
case Triple::GOFF:
report_fatal_error("Cannot initialize MC for GOFF object file format");
break;
case Triple::XCOFF:
Env = IsXCOFF;
initXCOFFMCObjectFileInfo(TT);
break;
case Triple::UnknownObjectFormat:
report_fatal_error("Cannot initialize MC for unknown object file format.");
break;
}
}
MCSection *MCObjectFileInfo::getDwarfComdatSection(const char *Name,
uint64_t Hash) const {
switch (TT.getObjectFormat()) {
case Triple::ELF:
return Ctx->getELFSection(Name, ELF::SHT_PROGBITS, ELF::SHF_GROUP, 0,
utostr(Hash));
case Triple::Wasm:
return Ctx->getWasmSection(Name, SectionKind::getMetadata(), utostr(Hash),
MCContext::GenericSectionID);
case Triple::MachO:
case Triple::COFF:
case Triple::GOFF:
case Triple::XCOFF:
case Triple::UnknownObjectFormat:
report_fatal_error("Cannot get DWARF comdat section for this object file "
"format: not implemented.");
break;
}
llvm_unreachable("Unknown ObjectFormatType");
}
MCSection *
MCObjectFileInfo::getStackSizesSection(const MCSection &TextSec) const {
if (Env != IsELF)
return StackSizesSection;
const MCSectionELF &ElfSec = static_cast<const MCSectionELF &>(TextSec);
unsigned Flags = ELF::SHF_LINK_ORDER;
StringRef GroupName;
if (const MCSymbol *Group = ElfSec.getGroup()) {
GroupName = Group->getName();
Flags |= ELF::SHF_GROUP;
}
return Ctx->getELFSection(".stack_sizes", ELF::SHT_PROGBITS, Flags, 0,
GroupName, ElfSec.getUniqueID(),
cast<MCSymbolELF>(TextSec.getBeginSymbol()));
}
MCSection *
MCObjectFileInfo::getBBAddrMapSection(const MCSection &TextSec) const {
if (Env != IsELF)
return nullptr;
const MCSectionELF &ElfSec = static_cast<const MCSectionELF &>(TextSec);
unsigned Flags = ELF::SHF_LINK_ORDER;
StringRef GroupName;
if (const MCSymbol *Group = ElfSec.getGroup()) {
GroupName = Group->getName();
Flags |= ELF::SHF_GROUP;
}
// Use the text section's begin symbol and unique ID to create a separate
// .llvm_bb_addr_map section associated with every unique text section.
return Ctx->getELFSection(".llvm_bb_addr_map", ELF::SHT_LLVM_BB_ADDR_MAP,
Flags, 0, GroupName, ElfSec.getUniqueID(),
cast<MCSymbolELF>(TextSec.getBeginSymbol()));
}
MCSection *
MCObjectFileInfo::getPseudoProbeSection(const MCSection *TextSec) const {
if (Env == IsELF) {
const auto *ElfSec = static_cast<const MCSectionELF *>(TextSec);
// Create a separate section for probes that comes with a comdat function.
if (const MCSymbol *Group = ElfSec->getGroup()) {
auto *S = static_cast<MCSectionELF *>(PseudoProbeSection);
auto Flags = S->getFlags() | ELF::SHF_GROUP;
return Ctx->getELFSection(S->getName(), S->getType(), Flags,
S->getEntrySize(), Group->getName());
}
}
return PseudoProbeSection;
}
MCSection *
MCObjectFileInfo::getPseudoProbeDescSection(StringRef FuncName) const {
if (Env == IsELF) {
// Create a separate comdat group for each function's descriptor in order
// for the linker to deduplicate. The duplication, must be from different
// tranlation unit, can come from:
// 1. Inline functions defined in header files;
// 2. ThinLTO imported funcions;
// 3. Weak-linkage definitions.
// Use a concatenation of the section name and the function name as the
// group name so that descriptor-only groups won't be folded with groups of
// code.
if (TT.supportsCOMDAT() && !FuncName.empty()) {
auto *S = static_cast<MCSectionELF *>(PseudoProbeDescSection);
auto Flags = S->getFlags() | ELF::SHF_GROUP;
return Ctx->getELFSection(S->getName(), S->getType(), Flags,
S->getEntrySize(),
S->getName() + "_" + FuncName);
}
}
return PseudoProbeDescSection;
}
Reference in New Issue View Git Blame Copy Permalink