llvm-project/clang/lib/CodeGen
Evgeniy Stepanov c5e7f56249 ARM MTE stack sanitizer.
Add "memtag" sanitizer that detects and mitigates stack memory issues
using armv8.5 Memory Tagging Extension.

It is similar in principle to HWASan, which is a software implementation
of the same idea, but there are enough differencies to warrant a new
sanitizer type IMHO. It is also expected to have very different
performance properties.

The new sanitizer does not have a runtime library (it may grow one
later, along with a "debugging" mode). Similar to SafeStack and
StackProtector, the instrumentation pass (in a follow up change) will be
inserted in all cases, but will only affect functions marked with the
new sanitize_memtag attribute.

Reviewers: pcc, hctim, vitalybuka, ostannard

Subscribers: srhines, mehdi_amini, javed.absar, kristof.beyls, hiraditya, cryptoad, steven_wu, dexonsmith, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D64169

llvm-svn: 366123
2019-07-15 20:02:23 +00:00
..
ABIInfo.h Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
Address.h Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
BackendUtil.cpp [NewPM] Port Sancov 2019-07-11 22:35:40 +00:00
CGAtomic.cpp add periods 2019-04-03 22:19:07 +00:00
CGBlocks.cpp [CodeGen][ObjC] Annotate retain-agnostic ObjC globals with attribute 2019-06-14 22:06:28 +00:00
CGBlocks.h Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
CGBuilder.h [BPF] Preserve debuginfo array/union/struct type/access index 2019-07-09 04:21:50 +00:00
CGBuiltin.cpp [SystemZ] Add support for new cpu architecture - arch13 2019-07-12 18:14:51 +00:00
CGCUDANV.cpp [clang][CodeGen] Remove std::move on temporary 2019-06-17 14:23:06 +00:00
CGCUDARuntime.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
CGCUDARuntime.h [HIP] Add the interface deriving the stub name of device kernels. 2019-06-17 12:51:36 +00:00
CGCXX.cpp Fix unused variable warning. NFCI. 2019-03-23 16:16:46 +00:00
CGCXXABI.cpp Remove two unnecessary wrappers of canPassInRegisters 2019-04-30 22:23:20 +00:00
CGCXXABI.h Remove two unnecessary wrappers of canPassInRegisters 2019-04-30 22:23:20 +00:00
CGCall.cpp Ensure Target Features always_inline error happens in C++ cases. 2019-06-21 22:29:32 +00:00
CGCall.h [opaque pointer types] Make EmitCall pass Function Types to 2019-02-07 01:15:41 +00:00
CGClass.cpp Rename CodeGenFunction::overlapFor* to getOverlapFor*. 2019-06-20 20:56:20 +00:00
CGCleanup.cpp [opaque pointer types] Cleanup CGBuilder's Create*GEP. 2019-02-09 22:22:28 +00:00
CGCleanup.h Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
CGCoroutine.cpp Delete dead stores 2019-07-12 14:04:34 +00:00
CGDebugInfo.cpp Revert "[CGDebugInfo] Simplify EmitFunctionDecl parameters, NFC" 2019-07-11 19:28:07 +00:00
CGDebugInfo.h Revert "[CGDebugInfo] Simplify EmitFunctionDecl parameters, NFC" 2019-07-11 19:28:07 +00:00
CGDecl.cpp NFC: Pass DataLayout into isBytewiseValue 2019-07-10 22:53:52 +00:00
CGDeclCXX.cpp ARM MTE stack sanitizer. 2019-07-15 20:02:23 +00:00
CGException.cpp [WebAssembly] Use rethrow intrinsic in the rethrow block 2019-03-16 05:39:12 +00:00
CGExpr.cpp fix unnamed fiefield issue and add tests for __builtin_preserve_access_index intrinsic 2019-07-15 15:42:41 +00:00
CGExprAgg.cpp [C++2a] Add __builtin_bit_cast, used to implement std::bit_cast 2019-07-02 18:28:13 +00:00
CGExprCXX.cpp Re-Revert Devirtualize destructor of final class. 2019-07-12 00:32:08 +00:00
CGExprComplex.cpp [C++2a] Add __builtin_bit_cast, used to implement std::bit_cast 2019-07-02 18:28:13 +00:00
CGExprConstant.cpp Change std::{lower,upper}_bound to llvm::{lower,upper}_bound or llvm::partition_point. NFC 2019-07-03 08:13:17 +00:00
CGExprScalar.cpp Treat the range of representable values of floating-point types as [-inf, +inf] not as [-max, +max]. 2019-07-06 21:05:52 +00:00
CGGPUBuiltin.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
CGLoopInfo.cpp [CodeGen] Generate follow-up metadata for loops with more than one transformation. 2019-04-01 17:47:41 +00:00
CGLoopInfo.h [CodeGen] Generate follow-up metadata for loops with more than one transformation. 2019-04-01 17:47:41 +00:00
CGNonTrivialStruct.cpp Add { } to silence compiler warning [NFC] 2019-04-11 06:57:12 +00:00
CGObjC.cpp Rename CodeGenFunction::overlapFor* to getOverlapFor*. 2019-06-20 20:56:20 +00:00
CGObjCGNU.cpp [gnustep-objc] Make the GNUstep v2 ABI work for Windows DLLs. 2019-03-31 11:22:33 +00:00
CGObjCMac.cpp Silence gcc warning "control reaches end of non-void function" [NFCI] 2019-07-05 06:12:24 +00:00
CGObjCRuntime.cpp [opaque pointer types] Pass function types for runtime function calls. 2019-02-05 16:42:33 +00:00
CGObjCRuntime.h [opaque pointer types] Pass function types for runtime function calls. 2019-02-05 16:42:33 +00:00
CGOpenCLRuntime.cpp [OpenCL] Simplify LLVM IR generated for OpenCL blocks 2019-02-21 11:02:10 +00:00
CGOpenCLRuntime.h [OpenCL] Simplify LLVM IR generated for OpenCL blocks 2019-02-21 11:02:10 +00:00
CGOpenMPRuntime.cpp Added mapping for pointers captured in Lambdas in OpenMP target regions, 2019-07-11 13:54:26 +00:00
CGOpenMPRuntime.h [OpenMP] Add support for handling declare target to clause when unified memory is required 2019-06-20 18:04:47 +00:00
CGOpenMPRuntimeNVPTX.cpp [HIP] Add GPU arch gfx1010, gfx1011, and gfx1012 2019-07-11 17:50:09 +00:00
CGOpenMPRuntimeNVPTX.h [OpenMP] Add support for registering requires directives with the runtime 2019-05-21 19:42:01 +00:00
CGRecordLayout.h Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
CGRecordLayoutBuilder.cpp P0840R2: support for [[no_unique_address]] attribute 2019-06-20 20:44:45 +00:00
CGStmt.cpp Ignore trailing NullStmts in StmtExprs for GCC compatibility. 2019-07-09 15:02:07 +00:00
CGStmtOpenMP.cpp [OPENMP]Fix PR41966: type mismatch in runtime functions. 2019-06-25 16:00:43 +00:00
CGVTT.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
CGVTables.cpp [CodeGen] Set construction vtable visibility after creating initializer 2019-02-11 20:13:42 +00:00
CGVTables.h Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
CGValue.h Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
CMakeLists.txt Make CodeGen depend on ASTMatchers 2019-06-26 14:13:43 +00:00
CodeGenABITypes.cpp Remove redundant FunctionDecl argument from a couple functions. 2019-02-02 01:48:23 +00:00
CodeGenAction.cpp [Remarks] Extend -fsave-optimization-record to specify the format 2019-06-17 16:06:00 +00:00
CodeGenFunction.cpp ARM MTE stack sanitizer. 2019-07-15 20:02:23 +00:00
CodeGenFunction.h fix unnamed fiefield issue and add tests for __builtin_preserve_access_index intrinsic 2019-07-15 15:42:41 +00:00
CodeGenModule.cpp ARM MTE stack sanitizer. 2019-07-15 20:02:23 +00:00
CodeGenModule.h C++ DR712 and others: handle non-odr-use resulting from an lvalue-to-rvalue conversion applied to a member access or similar not-quite-trivial lvalue expression. 2019-06-14 17:46:37 +00:00
CodeGenPGO.cpp [MS] Don't emit coverage for deleting dtors 2019-02-26 20:42:52 +00:00
CodeGenPGO.h Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
CodeGenTBAA.cpp Fix TBAA representation for zero-sized fields and unnamed bit-fields. 2019-06-22 21:30:43 +00:00
CodeGenTBAA.h Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
CodeGenTypeCache.h Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
CodeGenTypes.cpp [OpenCL] Change type of block pointer for OpenCL 2019-02-19 15:19:06 +00:00
CodeGenTypes.h IRGen: Remove StructorType; thread GlobalDecl through more code. NFCI. 2019-03-22 23:05:10 +00:00
ConstantEmitter.h Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
ConstantInitBuilder.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
CoverageMappingGen.cpp Reduce memory consumption of coverage dumps 2019-06-05 06:35:10 +00:00
CoverageMappingGen.h Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
EHScopeStack.h Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
ItaniumCXXABI.cpp [OpenCL][PR41727] Prevent ICE on global dtors 2019-07-15 11:58:10 +00:00
MacroPPCallbacks.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
MacroPPCallbacks.h Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
MicrosoftCXXABI.cpp [COFF, ARM64] Fix ABI implementation of struct returns 2019-05-03 21:12:24 +00:00
ModuleBuilder.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
ObjectFilePCHContainerOperations.cpp [Bitcode] Move Bitstream to a separate library 2019-07-03 22:40:07 +00:00
PatternInit.cpp CodeGet: Init 32bit pointers with 0xFFFFFFFF 2019-07-12 17:21:55 +00:00
PatternInit.h Variable auto-init: also auto-init alloca 2019-04-12 00:11:27 +00:00
README.txt
SanitizerMetadata.cpp ARM MTE stack sanitizer. 2019-07-15 20:02:23 +00:00
SanitizerMetadata.h Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
SwiftCallingConv.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
TargetInfo.cpp [clang] Preserve names of addrspacecast'ed values. 2019-07-10 17:10:05 +00:00
TargetInfo.h [OpenCL][PR41727] Prevent ICE on global dtors 2019-07-15 11:58:10 +00:00
VarBypassDetector.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
VarBypassDetector.h Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00

README.txt

IRgen optimization opportunities.

//===---------------------------------------------------------------------===//

The common pattern of
--
short x; // or char, etc
(x == 10)
--
generates an zext/sext of x which can easily be avoided.

//===---------------------------------------------------------------------===//

Bitfields accesses can be shifted to simplify masking and sign
extension. For example, if the bitfield width is 8 and it is
appropriately aligned then is is a lot shorter to just load the char
directly.

//===---------------------------------------------------------------------===//

It may be worth avoiding creation of alloca's for formal arguments
for the common situation where the argument is never written to or has
its address taken. The idea would be to begin generating code by using
the argument directly and if its address is taken or it is stored to
then generate the alloca and patch up the existing code.

In theory, the same optimization could be a win for block local
variables as long as the declaration dominates all statements in the
block.

NOTE: The main case we care about this for is for -O0 -g compile time
performance, and in that scenario we will need to emit the alloca
anyway currently to emit proper debug info. So this is blocked by
being able to emit debug information which refers to an LLVM
temporary, not an alloca.

//===---------------------------------------------------------------------===//

We should try and avoid generating basic blocks which only contain
jumps. At -O0, this penalizes us all the way from IRgen (malloc &
instruction overhead), all the way down through code generation and
assembly time.

On 176.gcc:expr.ll, it looks like over 12% of basic blocks are just
direct branches!

//===---------------------------------------------------------------------===//