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2023-09-13[InlineAsm] wrap ConstraintCode in enum class NFC (#66003)Nick Desaulniers
Similar to commit 2fad6e69851e ("[InlineAsm] wrap Kind in enum class NFC") Fix the TODOs added in commit 93bd428742f9 ("[InlineAsm] refactor InlineAsm class NFC (#65649)")
2023-09-11[InlineAsm] refactor InlineAsm class NFC (#65649)Nick Desaulniers
I would like to steal one of these bits to denote whether a kind may be spilled by the register allocator or not, but I'm afraid to touch of any this code using bitwise operands. Make flags a first class type using bitfields, rather than launder data around via `unsigned`.
2023-08-31Emit the CodeView `S_ARMSWITCHTABLE` debug symbol for jump tablesDaniel Paoliello
The CodeView `S_ARMSWITCHTABLE` debug symbol is used to describe the layout of a jump table, it contains the following information: * The address of the branch instruction that uses the jump table. * The address of the jump table. * The "base" address that the values in the jump table are relative to. * The type of each entry (absolute pointer, a relative integer, a relative integer that is shifted). Together this information can be used by debuggers and binary analysis tools to understand what an jump table indirect branch is doing and where it might jump to. Documentation for the symbol can be found in the Microsoft PDB library dumper: https://github.com/microsoft/microsoft-pdb/blob/0fe89a942f9a0f8e061213313e438884f4c9b876/cvdump/dumpsym7.cpp#L5518 This change adds support to LLVM to emit the `S_ARMSWITCHTABLE` debug symbol as well as to dump it out (for testing purposes). Reviewed By: efriedma Differential Revision: https://reviews.llvm.org/D149367
2023-08-31[InlineAsm] wrap Kind in enum class NFCNick Desaulniers
Should add some minor type safety to the use of this information, since there's quite a bit of metadata being laundered through an `unsigned`. I'm looking to potentially add more bitfields to that `unsigned`, but I find InlineAsm's big ol' bag of enum values and usage of `unsigned` confusing, type-unsafe, and un-ergonomic. These can probably be better abstracted. I think the lack of static_cast outside of InlineAsm indicates the prior code smell fixed here. Reviewed By: qcolombet Differential Revision: https://reviews.llvm.org/D159242
2023-08-25Revert "Emit the CodeView `S_ARMSWITCHTABLE` debug symbol for jump tables"Arthur Eubanks
This reverts commit 8d0c3db388143f4e058b5f513a70fd5d089d51c3. Causes crashes, see comments in https://reviews.llvm.org/D149367. Some follow-up fixes are also reverted: This reverts commit 636269f4fca44693bfd787b0a37bb0328ffcc085. This reverts commit 5966079cf4d4de0285004eef051784d0d9f7a3a6. This reverts commit e7294dbc85d24a08c716d9babbe7f68390cf219b.
2023-08-25Emit the CodeView `S_ARMSWITCHTABLE` debug symbol for jump tablesDaniel Paoliello
The CodeView `S_ARMSWITCHTABLE` debug symbol is used to describe the layout of a jump table, it contains the following information: * The address of the branch instruction that uses the jump table. * The address of the jump table. * The "base" address that the values in the jump table are relative to. * The type of each entry (absolute pointer, a relative integer, a relative integer that is shifted). Together this information can be used by debuggers and binary analysis tools to understand what an jump table indirect branch is doing and where it might jump to. Documentation for the symbol can be found in the Microsoft PDB library dumper: https://github.com/microsoft/microsoft-pdb/blob/0fe89a942f9a0f8e061213313e438884f4c9b876/cvdump/dumpsym7.cpp#L5518 This change adds support to LLVM to emit the `S_ARMSWITCHTABLE` debug symbol as well as to dump it out (for testing purposes). Reviewed By: efriedma Differential Revision: https://reviews.llvm.org/D149367
2023-08-11AMDGPU: Check for implicit defs before constant folding instructionMatt Arsenault
Can't delete the constant folded instruction if scc is used. Fixes #63986 https://reviews.llvm.org/D157504
2023-08-02[DebugInfo] Fix crash when printing malformed DBG machine instructionsJay Foad
MachineVerifier does not check that DBG_VALUE, DBG_VALUE_LIST and DBG_INSTR_REF have the expected number of operands, so printing them (e.g. with -print-after-all) should not crash. Differential Revision: https://reviews.llvm.org/D156226
2023-06-28[MachineInst] Bump NumOperands back up to 24bitsJon Roelofs
In https://reviews.llvm.org/D149445, it was lowered from 32 to 16bits, which broke an internal project of ours. The relevant code being compiled is a fairly large nested switch that results in a PHI node with 65k+ operands, which can't easily be turned into a table for perf reasons. This change unifies `NumOperands`, `Flags`, and `AsmPrinterFlags` into a packed 7-byte struct, which `CapOperands` can follow as the 8th byte, rounding it up to a nice alignment before the `Info` field. rdar://111217742&109362033 Differential revision: https://reviews.llvm.org/D153791
2023-06-01[SDAG] Preserve unpredictable metadata, teach X86CmovConversion to respect ↵Dávid Bolvanský
this metadata Sometimes an developer would like to have more control over cmov vs branch. We have unpredictable metadata in LLVM IR, but currently it is ignored by X86 backend. Propagate this metadata and avoid cmov->branch conversion in X86CmovConversion for cmov with this metadata. Example: ``` int MaxIndex(int n, int *a) { int t = 0; for (int i = 1; i < n; i++) { // cmov is converted to branch by X86CmovConversion if (a[i] > a[t]) t = i; } return t; } int MaxIndex2(int n, int *a) { int t = 0; for (int i = 1; i < n; i++) { // cmov is preserved if (__builtin_unpredictable(a[i] > a[t])) t = i; } return t; } ``` Reviewed By: nikic Differential Revision: https://reviews.llvm.org/D118118
2023-05-18[DebugInfo][InstrRef] Prettyprint metadataHeejin Ahn
Some metadata prettyprinting, including variable prettyprinting and debug line info comments, is currently only supported for `DBG_VALUE`. This allows `DBG_INSTR_REF` can be printed in the same way. Reviewed By: jmorse Differential Revision: https://reviews.llvm.org/D150620
2023-05-02[MachineInst] Switch NumOperands to 16bitsDávid Bolvanský
Decrease NumOperands from 32 to 16bits (matches MCInstrDesc) so we can use saved bits to extend Flags (https://reviews.llvm.org/D118118). Reviewed By: barannikov88 Differential Revision: https://reviews.llvm.org/D149445
2023-05-03Restore CodeGen/LowLevelType from `Support`NAKAMURA Takumi
This is rework of; - D30046 (LLT) Since I have introduced `llvm-min-tblgen` as D146352, `llvm-tblgen` may depend on `CodeGen`. `LowLevlType.h` originally belonged to `CodeGen`. Almost all userse are still under `CodeGen` or `Target`. I think `CodeGen` is the right place to put `LowLevelType.h`. `MachineValueType.h` may be moved as well. (later, D149024) I have made many modules depend on `CodeGen`. It is consistent but inefficient. It will be split out later, D148769 Besides, I had to isolate MVT and LLT in modmap, since `llvm::PredicateInfo` clashes between `TableGen/CodeGenSchedule.h` and `Transforms/Utils/PredicateInfo.h`. (I think better to introduce namespace llvm::TableGen) Depends on D145937, D146352, and D148768. Differential Revision: https://reviews.llvm.org/D148767
2023-04-12[GlobalISel][NFC] Add MachineInstr::getFirst[N]{Regs,LLTs}() helpers to ↵Amara Emerson
extract regs & types. These reduce the typing and clutter from: Register Dst = MI.getOperand(0).getReg(); Register Src1 = MI.getOperand(1).getReg(); Register Src2 = MI.getOperand(2).getReg(); Register Src3 = MI.getOperand(3).getReg(); LLT DstTy = MRI.getType(Dst); ... etc etc To just: auto [Dst, Src1, Src2, Src3] = MI.getFirst4Regs(); auto [DstTy, Src1Ty, Src2Ty, Src3Ty] = MI.getFirst4LLTs(); Or even more concise: auto [Dst, DstTy, Src1, Src1Ty, Src2, Src2Ty, Src3, Src3Ty] = MI.getFirst4RegLLTs(); Differential Revision: https://reviews.llvm.org/D144687
2023-01-23[MC] Define and use MCInstrDesc implicit_uses and implicit_defs. NFC.Jay Foad
The new methods return a range for easier iteration. Use them everywhere instead of getImplicitUses, getNumImplicitUses, getImplicitDefs and getNumImplicitDefs. A future patch will remove the old methods. In some use cases the new methods are less efficient because they always have to scan the whole uses/defs array to count its length, but that will be fixed in a future patch by storing the number of implicit uses/defs explicitly in MCInstrDesc. At that point there will be no need to 0-terminate the arrays. Differential Revision: https://reviews.llvm.org/D142215
2023-01-23[MC] Make more use of MCInstrDesc::operands. NFC.Jay Foad
Change MCInstrDesc::operands to return an ArrayRef so we can easily use it everywhere instead of the (IMHO ugly) opInfo_begin and opInfo_end. A future patch will remove opInfo_begin and opInfo_end. Also use it instead of raw access to the OpInfo pointer. A future patch will remove this pointer. Differential Revision: https://reviews.llvm.org/D142213
2023-01-13[CodeGen] Remove uses of Register::isPhysicalRegister/isVirtualRegister. NFCCraig Topper
Use isPhysical/isVirtual methods. Reviewed By: foad Differential Revision: https://reviews.llvm.org/D141715
2023-01-06[DebugInfo][NFC] Add new MachineOperand type and change DBG_INSTR_REF syntaxStephen Tozer
This patch makes two notable changes to the MIR debug info representation, which result in different MIR output but identical final DWARF output (NFC w.r.t. the full compilation). The two changes are: * The introduction of a new MachineOperand type, MO_DbgInstrRef, which consists of two unsigned numbers that are used to index an instruction and an output operand within that instruction, having a meaning identical to first two operands of the current DBG_INSTR_REF instruction. This operand is only used in DBG_INSTR_REF (see below). * A change in syntax for the DBG_INSTR_REF instruction, shuffling the operands to make it resemble DBG_VALUE_LIST instead of DBG_VALUE, and replacing the first two operands with a single MO_DbgInstrRef-type operand. This patch is the first of a set that will allow DBG_INSTR_REF instructions to refer to multiple machine locations in the same manner as DBG_VALUE_LIST. Reviewed By: jmorse Differential Revision: https://reviews.llvm.org/D129372
2023-01-04[MC] Consistently use MCInstrDesc::getImplicitUses and getImplicitDefs. NFC.Jay Foad
2022-12-19[DebugInfo] Add function to test debug values for equivalenceStephen Tozer
This patch adds a new function that can be used to check all the properties, other than the machine values, of a pair of debug values for equivalence. This is done by folding the "directness" into the expression, converting the expression to variadic form if it is not already in that form, and then comparing directly. In a few places which check whether two debug values are identical to see if their ranges can be merged, this function will correctly identify cases where two debug values are expressed differently but have the same meaning, allowing those ranges to be correctly merged. Differential Revision: https://reviews.llvm.org/D136173
2022-12-13[CodeGen] llvm::Optional => std::optionalFangrui Song
2022-12-06[ADT] Don't including None.h (NFC)Kazu Hirata
These source files no longer use None, so they do not need to include None.h. This is part of an effort to migrate from llvm::Optional to std::optional: https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716
2022-12-02[CodeGen] Use std::nullopt instead of None (NFC)Kazu Hirata
This patch mechanically replaces None with std::nullopt where the compiler would warn if None were deprecated. The intent is to reduce the amount of manual work required in migrating from Optional to std::optional. This is part of an effort to migrate from llvm::Optional to std::optional: https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716
2022-10-13Propagate tied operands when copying a MachineInstr.Simon Tatham
MachineInstr's copy constructor works by calling the addOperand method to add each operand of the old MachineInstr to the new one, one by one. But addOperand deliberately avoids trying to replicate ties between operands, on the grounds that the tie refers to operands by index, and the indices aren't necessarily finalized yet. This led to a code generation fault when the machine pipeliner cloned an Arm conditional instruction, and lost the tie between the output register and the input value to be used when the condition failed to execute. Reviewed By: dmgreen Differential Revision: https://reviews.llvm.org/D135434
2022-09-06[MachineInstr] Allow setting PCSections in ExtraInfoMarco Elver
Provide MachineInstr::setPCSection(), to propagate relevant metadata through the backend. Use ExtraInfo to store the metadata. Reviewed By: vitalybuka Differential Revision: https://reviews.llvm.org/D130876
2022-08-24KCFI sanitizerSami Tolvanen
The KCFI sanitizer, enabled with `-fsanitize=kcfi`, implements a forward-edge control flow integrity scheme for indirect calls. It uses a !kcfi_type metadata node to attach a type identifier for each function and injects verification code before indirect calls. Unlike the current CFI schemes implemented in LLVM, KCFI does not require LTO, does not alter function references to point to a jump table, and never breaks function address equality. KCFI is intended to be used in low-level code, such as operating system kernels, where the existing schemes can cause undue complications because of the aforementioned properties. However, unlike the existing schemes, KCFI is limited to validating only function pointers and is not compatible with executable-only memory. KCFI does not provide runtime support, but always traps when a type mismatch is encountered. Users of the scheme are expected to handle the trap. With `-fsanitize=kcfi`, Clang emits a `kcfi` operand bundle to indirect calls, and LLVM lowers this to a known architecture-specific sequence of instructions for each callsite to make runtime patching easier for users who require this functionality. A KCFI type identifier is a 32-bit constant produced by taking the lower half of xxHash64 from a C++ mangled typename. If a program contains indirect calls to assembly functions, they must be manually annotated with the expected type identifiers to prevent errors. To make this easier, Clang generates a weak SHN_ABS `__kcfi_typeid_<function>` symbol for each address-taken function declaration, which can be used to annotate functions in assembly as long as at least one C translation unit linked into the program takes the function address. For example on AArch64, we might have the following code: ``` .c: int f(void); int (*p)(void) = f; p(); .s: .4byte __kcfi_typeid_f .global f f: ... ``` Note that X86 uses a different preamble format for compatibility with Linux kernel tooling. See the comments in `X86AsmPrinter::emitKCFITypeId` for details. As users of KCFI may need to locate trap locations for binary validation and error handling, LLVM can additionally emit the locations of traps to a `.kcfi_traps` section. Similarly to other sanitizers, KCFI checking can be disabled for a function with a `no_sanitize("kcfi")` function attribute. Relands 67504c95494ff05be2a613129110c9bcf17f6c13 with a fix for 32-bit builds. Reviewed By: nickdesaulniers, kees, joaomoreira, MaskRay Differential Revision: https://reviews.llvm.org/D119296
2022-08-24Revert "KCFI sanitizer"Sami Tolvanen
This reverts commit 67504c95494ff05be2a613129110c9bcf17f6c13 as using PointerEmbeddedInt to store 32 bits breaks 32-bit arm builds.
2022-08-24KCFI sanitizerSami Tolvanen
The KCFI sanitizer, enabled with `-fsanitize=kcfi`, implements a forward-edge control flow integrity scheme for indirect calls. It uses a !kcfi_type metadata node to attach a type identifier for each function and injects verification code before indirect calls. Unlike the current CFI schemes implemented in LLVM, KCFI does not require LTO, does not alter function references to point to a jump table, and never breaks function address equality. KCFI is intended to be used in low-level code, such as operating system kernels, where the existing schemes can cause undue complications because of the aforementioned properties. However, unlike the existing schemes, KCFI is limited to validating only function pointers and is not compatible with executable-only memory. KCFI does not provide runtime support, but always traps when a type mismatch is encountered. Users of the scheme are expected to handle the trap. With `-fsanitize=kcfi`, Clang emits a `kcfi` operand bundle to indirect calls, and LLVM lowers this to a known architecture-specific sequence of instructions for each callsite to make runtime patching easier for users who require this functionality. A KCFI type identifier is a 32-bit constant produced by taking the lower half of xxHash64 from a C++ mangled typename. If a program contains indirect calls to assembly functions, they must be manually annotated with the expected type identifiers to prevent errors. To make this easier, Clang generates a weak SHN_ABS `__kcfi_typeid_<function>` symbol for each address-taken function declaration, which can be used to annotate functions in assembly as long as at least one C translation unit linked into the program takes the function address. For example on AArch64, we might have the following code: ``` .c: int f(void); int (*p)(void) = f; p(); .s: .4byte __kcfi_typeid_f .global f f: ... ``` Note that X86 uses a different preamble format for compatibility with Linux kernel tooling. See the comments in `X86AsmPrinter::emitKCFITypeId` for details. As users of KCFI may need to locate trap locations for binary validation and error handling, LLVM can additionally emit the locations of traps to a `.kcfi_traps` section. Similarly to other sanitizers, KCFI checking can be disabled for a function with a `no_sanitize("kcfi")` function attribute. Reviewed By: nickdesaulniers, kees, joaomoreira, MaskRay Differential Revision: https://reviews.llvm.org/D119296
2022-07-31[RISCV] Pre-RA expand pseudos passLuís Marques
Expand load address pseudo-instructions earlier (pre-ra) to allow follow-up patches to fold the addi of PseudoLLA instructions into the immediate operand of load/store instructions. Differential Revision: https://reviews.llvm.org/D123264
2022-07-18CodeGen: Remove AliasAnalysis from regallocMatt Arsenault
This was stored in LiveIntervals, but not actually used for anything related to LiveIntervals. It was only used in one check for if a load instruction is rematerializable. I also don't think this was entirely correct, since it was implicitly assuming constant loads are also dereferenceable. Remove this and rely only on the invariant+dereferenceable flags in the memory operand. Set the flag based on the AA query upfront. This should have the same net benefit, but has the possible disadvantage of making this AA query nonlazy. Preserve the behavior of assuming pointsToConstantMemory implying dereferenceable for now, but maybe this should be changed.
2022-07-17[CodeGen] Qualify auto variables in for loops (NFC)Kazu Hirata
2022-06-25CodeGen: Use else if between Value and PseudoSourceValue casesMatt Arsenault
These are mutually exclusive.
2022-03-16[NFC][CodeGen] Rename some functions in MachineInstr.h and remove duplicated ↵Shengchen Kan
comments
2022-03-16Cleanup codegen includesserge-sans-paille
This is a (fixed) recommit of https://reviews.llvm.org/D121169 after: 1061034926 before: 1063332844 Discourse thread: https://discourse.llvm.org/t/include-what-you-use-include-cleanup Differential Revision: https://reviews.llvm.org/D121681
2022-03-10Revert "Cleanup codegen includes"Nico Weber
This reverts commit 7f230feeeac8a67b335f52bd2e900a05c6098f20. Breaks CodeGenCUDA/link-device-bitcode.cu in check-clang, and many LLVM tests, see comments on https://reviews.llvm.org/D121169
2022-03-10Cleanup codegen includesserge-sans-paille
after: 1061034926 before: 1063332844 Differential Revision: https://reviews.llvm.org/D121169
2022-03-01[nfc][codegen] Move RegisterBank[Info].h under CodeGenMircea Trofin
This wraps up from D119053. The 2 headers are moved as described, fixed file headers and include guards, updated all files where the old paths were detected (simple grep through the repo), and `clang-format`-ed it all. Differential Revision: https://reviews.llvm.org/D119876
2022-02-21MIR: Start diagnosing too many operands on an instructionMatt Arsenault
Previously this would just assert which was annoying and didn't point to the specific instruction/operand.
2021-12-06[NFC][MachineInstr] Rename some vars to conform to coding styleMircea Trofin
2021-12-05[GlobalISel] Allow DBG_VALUE to use undefined vregs before LiveDebugValues.Jack Andersen
Expanding on D109750. Since `DBG_VALUE` instructions have final register validity determined in `LDVImpl::handleDebugValue`, there is no apparent reason to immediately prune unused register operands as their defs are erased. Consequently, this renders `MachineInstr::eraseFromParentAndMarkDBGValuesForRemoval` moot; gaining a substantial performance improvement. The only necessary changes involve making relevant passes consider invalid DBG_VALUE vregs uses as valid. Reviewed By: MatzeB Differential Revision: https://reviews.llvm.org/D112852
2021-11-25[llvm] Use range-based for loops (NFC)Kazu Hirata
2021-10-07[MachineInstr] Move MIParser's DBG_VALUE RegState::Debug invariant into ↵Jack Andersen
MachineInstr::addOperand Based on the reasoning of D53903, register operands of DBG_VALUE are invariably treated as RegState::Debug operands. This change enforces this invariant as part of MachineInstr::addOperand so that all passes emit this flag consistently. RegState::Debug is inconsistently set on DBG_VALUE registers throughout LLVM. This runs the risk of a filtering iterator like MachineRegisterInfo::reg_nodbg_iterator to process these operands erroneously when not parsed from MIR sources. This issue was observed in the development of the llvm-mos fork which adds a backend that relies on physical register operands much more than existing targets. Physical RegUnit 0 has the same numeric encoding as $noreg (indicating an undef for DBG_VALUE). Allowing debug operands into the machine scheduler correlates $noreg with RegUnit 0 (i.e. a collision of register numbers with different zero semantics). Eventually, this causes an assert where DBG_VALUE instructions are prohibited from participating in live register ranges. Reviewed By: MatzeB, StephenTozer Differential Revision: https://reviews.llvm.org/D110105
2021-07-22[clang] Use i64 for the !srcloc metadata on asm IR nodes.Simon Tatham
This is part of a patch series working towards the ability to make SourceLocation into a 64-bit type to handle larger translation units. !srcloc is generated in clang codegen, and pulled back out by llvm functions like AsmPrinter::emitInlineAsm that need to report errors in the inline asm. From there it goes to LLVMContext::emitError, is stored in DiagnosticInfoInlineAsm, and ends up back in clang, at BackendConsumer::InlineAsmDiagHandler(), which reconstitutes a true clang::SourceLocation from the integer cookie. Throughout this code path, it's now 64-bit rather than 32, which means that if SourceLocation is expanded to a 64-bit type, this error report won't lose half of the data. The compiler will tolerate both of i32 and i64 !srcloc metadata in input IR without faulting. Test added in llvm/MC. (The semantic accuracy of the metadata is another matter, but I don't know of any situation where that matters: if you're reading an IR file written by a previous run of clang, you don't have the SourceManager that can relate those source locations back to the original source files.) Original version of the patch by Mikhail Maltsev. Reviewed By: dexonsmith Differential Revision: https://reviews.llvm.org/D105491
2021-07-01[DebugInfo][InstrRef][1/4] Support transformations that widen valuesJeremy Morse
Very late in compilation, backends like X86 will perform optimisations like this: $cx = MOV16rm $rax, ... -> $rcx = MOV64rm $rax, ... Widening the load from 16 bits to 64 bits. SEeing how the lower 16 bits remain the same, this doesn't affect execution. However, any debug instruction reference to the defined operand now refers to a 64 bit value, nto a 16 bit one, which might be unexpected. Elsewhere in codegen, there's often this pattern: CALL64pcrel32 @foo, implicit-def $rax %0:gr64 = COPY $rax %1:gr32 = COPY %0.sub_32bit Where we want to refer to the definition of $eax by the call, but don't want to refer the copies (they don't define values in the way LiveDebugValues sees it). To solve this, add a subregister field to the existing "substitutions" facility, so that we can describe a field within a larger value definition. I would imagine that this would be used most often when a value is widened, and we need to refer to the original, narrower definition. Differential Revision: https://reviews.llvm.org/D88891
2021-04-09[NFC][AA] Prepare to convert AliasResult to class with PartialAlias offset.dfukalov
Main reason is preparation to transform AliasResult to class that contains offset for PartialAlias case. Reviewed By: asbirlea Differential Revision: https://reviews.llvm.org/D98027
2021-03-10[DebugInfo] Handle DBG_VALUES with multiple variable location operands in MIRStephen Tozer
This patch adds handling for DBG_VALUE_LIST in the MIR-passes (after finalize-isel), excluding the debug liveness passes and DWARF emission. This most significantly affects MachineSink, which now needs to consider all used registers of a debug value when sinking, but for most passes this change is simply replacing getDebugOperand(0) with an iteration over all debug operands. Differential Revision: https://reviews.llvm.org/D92578
2021-03-05Reapply "[DebugInfo] Add new instruction and DIExpression operator for ↵Stephen Tozer
variadic debug values" Rewrites test to use correct architecture triple; fixes incorrect reference in SourceLevelDebugging doc; simplifies `spillReg` behaviour so as to not be dependent on changes elsewhere in the patch stack. This reverts commit d2000b45d033c06dc7973f59909a0ad12887ff51.
2021-03-04Revert "[DebugInfo] Add new instruction and DIExpression operator for ↵Stephen Tozer
variadic debug values" This reverts commit d07f106f4a48b6e941266525b6f7177834d7b74e.
2021-03-04[DebugInfo] Add new instruction and DIExpression operator for variadic debug ↵gbtozers
values This patch adds a new instruction that can represent variadic debug values, DBG_VALUE_VAR. This patch alone covers the addition of the instruction and a set of basic code changes in MachineInstr and a few adjacent areas, but does not correctly handle variadic debug values outside of these areas, nor does it generate them at any point. The new instruction is similar to the existing DBG_VALUE instruction, with the following differences: the operands are in a different order, any number of values may be used in the instruction following the Variable and Expression operands (these are referred to in code as “debug operands”) and are indexed from 0 so that getDebugOperand(X) == getOperand(X+2), and the Expression in a DBG_VALUE_VAR must use the DW_OP_LLVM_arg operator to pass arguments into the expression. The new DW_OP_LLVM_arg operator is only valid in expressions appearing in a DBG_VALUE_VAR; it takes a single argument and pushes the debug operand at the index given by the argument onto the Expression stack. For example the sub-expression `DW_OP_LLVM_arg, 0` has the meaning “Push the debug operand at index 0 onto the expression stack.” Differential Revision: https://reviews.llvm.org/D82363
2021-02-15[CodeGen] Use range-based for loops (NFC)Kazu Hirata