[RISCV][CFI] add function epilogue cfi information #2
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This patch adds CFI instructions in a function epilogue, that allows lldb to obtain a valid backtrace at the end of functions.
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daniilavdeev
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Oct 1, 2024
…ext is not fully initialized (llvm#110481) As this comment around target initialization implies: ``` // This can be NULL if we don't know anything about the architecture or if // the target for an architecture isn't enabled in the llvm/clang that we // built ``` There are cases where we might fail to call `InitBuiltinTypes` when creating the backing `ASTContext` for a `TypeSystemClang`. If that happens, the builtins `QualType`s, e.g., `VoidPtrTy`/`IntTy`/etc., are not initialized and dereferencing them as we do in `GetBuiltinTypeForEncodingAndBitSize` (and other places) will lead to nullptr-dereferences. Example backtrace: ``` (lldb) run Assertion failed: (!isNull() && "Cannot retrieve a NULL type pointer"), function getCommonPtr, file Type.h, line 958. Process 2680 stopped * thread llvm#15, name = '<lldb.process.internal-state(pid=2712)>', stop reason = hit program assert frame llvm#4: 0x000000010cdf3cdc liblldb.20.0.0git.dylib`DWARFASTParserClang::ExtractIntFromFormValue(lldb_private::CompilerType const&, lldb_private::plugin::dwarf::DWARFFormValue const&) const (.cold.1) + liblldb.20.0.0git.dylib`DWARFASTParserClang::ParseObjCMethod(lldb_private::ObjCLanguage::MethodName const&, lldb_private::plugin::dwarf::DWARFDIE const&, lldb_private::CompilerType, ParsedDWARFTypeAttributes , bool) (.cold.1): -> 0x10cdf3cdc <+0>: stp x29, x30, [sp, #-0x10]! 0x10cdf3ce0 <+4>: mov x29, sp 0x10cdf3ce4 <+8>: adrp x0, 545 0x10cdf3ce8 <+12>: add x0, x0, #0xa25 ; "ParseObjCMethod" Target 0: (lldb) stopped. (lldb) bt * thread llvm#15, name = '<lldb.process.internal-state(pid=2712)>', stop reason = hit program assert frame #0: 0x0000000180d08600 libsystem_kernel.dylib`__pthread_kill + 8 frame #1: 0x0000000180d40f50 libsystem_pthread.dylib`pthread_kill + 288 frame #2: 0x0000000180c4d908 libsystem_c.dylib`abort + 128 frame llvm#3: 0x0000000180c4cc1c libsystem_c.dylib`__assert_rtn + 284 * frame llvm#4: 0x000000010cdf3cdc liblldb.20.0.0git.dylib`DWARFASTParserClang::ExtractIntFromFormValue(lldb_private::CompilerType const&, lldb_private::plugin::dwarf::DWARFFormValue const&) const (.cold.1) + frame llvm#5: 0x0000000109d30acc liblldb.20.0.0git.dylib`lldb_private::TypeSystemClang::GetBuiltinTypeForEncodingAndBitSize(lldb::Encoding, unsigned long) + 1188 frame llvm#6: 0x0000000109aaaed4 liblldb.20.0.0git.dylib`DynamicLoaderMacOS::NotifyBreakpointHit(void*, lldb_private::StoppointCallbackContext*, unsigned long long, unsigned long long) + 384 ``` This patch adds a one-time user-visible warning for when we fail to initialize the AST to indicate that initialization went wrong for the given target. Additionally, we add checks for whether one of the `ASTContext` `QualType`s is invalid before dereferencing any builtin types. The warning would look as follows: ``` (lldb) target create "a.out" Current executable set to 'a.out' (arm64). (lldb) b main warning: Failed to initialize builtin ASTContext types for target 'some-unknown-triple'. Printing variables may behave unexpectedly. Breakpoint 1: where = a.out`main + 8 at stepping.cpp:5:14, address = 0x0000000100003f90 ``` rdar://134869779
daniilavdeev
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Oct 16, 2024
Fixes llvm#102703. https://godbolt.org/z/nfj8xsb1Y The following pattern: ``` %2 = and i32 %0, 254 %3 = icmp eq i32 %2, 0 ``` is optimised by instcombine into: ```%3 = icmp ult i32 %0, 2``` However, post instcombine leads to worse aarch64 than the unoptimised version. Pre instcombine: ``` tst w0, #0xfe cset w0, eq ret ``` Post instcombine: ``` and w8, w0, #0xff cmp w8, #2 cset w0, lo ret ``` In the unoptimised version, SelectionDAG converts `SETCC (AND X 254) 0 EQ` into `CSEL 0 1 1 (ANDS X 254)`, which gets emitted as a `tst`. In the optimised version, SelectionDAG converts `SETCC (AND X 255) 2 ULT` into `CSEL 0 1 2 (SUBS (AND X 255) 2)`, which gets emitted as an `and`/`cmp`. This PR adds an optimisation to `AArch64ISelLowering`, converting `SETCC (AND X Y) Z ULT` into `SETCC (AND X (Y & ~(Z - 1))) 0 EQ` when `Z` is a power of two. This makes SelectionDAG/Codegen produce the same optimised code for both examples.
daniilavdeev
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Oct 16, 2024
…1409)" This reverts commit a89e016. This is being reverted because it broke the test: Unwind/trap_frame_sym_ctx.test /Users/ec2-user/jenkins/workspace/llvm.org/lldb-cmake/llvm-project/lldb/test/Shell/Unwind/trap_frame_sym_ctx.test:21:10: error: CHECK: expected string not found in input CHECK: frame #2: {{.*}}`main
daniilavdeev
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Oct 30, 2024
…ates explicitly specialized for an implicitly instantiated class template specialization (llvm#113464) Consider the following: ``` template<typename T> struct A { template<typename U> struct B { static constexpr int x = 0; // #1 }; template<typename U> struct B<U*> { static constexpr int x = 1; // #2 }; }; template<> template<typename U> struct A<long>::B { static constexpr int x = 2; // llvm#3 }; static_assert(A<short>::B<int>::y == 0); // uses #1 static_assert(A<short>::B<int*>::y == 1); // uses #2 static_assert(A<long>::B<int>::y == 2); // uses llvm#3 static_assert(A<long>::B<int*>::y == 2); // uses llvm#3 ``` According to [temp.spec.partial.member] p2: > If the primary member template is explicitly specialized for a given (implicit) specialization of the enclosing class template, the partial specializations of the member template are ignored for this specialization of the enclosing class template. If a partial specialization of the member template is explicitly specialized for a given (implicit) specialization of the enclosing class template, the primary member template and its other partial specializations are still considered for this specialization of the enclosing class template. The example above fails to compile because we currently don't implement [temp.spec.partial.member] p2. This patch implements the wording, fixing llvm#51051.
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[RISCV][CFI] add function epilogue cfi information
This patch adds CFI instructions in a function epilogue, that allows
lldb to obtain a valid backtrace at the end of functions.
[RISCV] update tests