Date: Wed, 30 Dec 2015 21:12:14 +0000 From: bugzilla-noreply@freebsd.org To: freebsd-bugs@FreeBSD.org Subject: [Bug 205663] clang++ 3.7.1 gets Bus Errors during compilation on arm that has SCTLR bit[1]==1 (alignment required) Message-ID: <bug-205663-8-McO6fXl7TG@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-205663-8@https.bugs.freebsd.org/bugzilla/> References: <bug-205663-8@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=205663 --- Comment #4 from Mark Millard <markmi@dsl-only.net> --- I've added the following new information on llvm's bugzilla report. Basically alignas use can avoid the alignment problems but there are lots of places that would need it in order for clang++ to work overall for SCTLR bit[1]==1. The following change eliminates the specific Bus Error in clang and allows the 11 line program to compile on an rpi2 --but causes include/clang/AST/Type.h to pollute a namespace via <cstddef> use: # svnlite diff /usr/src/contrib/llvm/ Index: /usr/src/contrib/llvm/tools/clang/include/clang/AST/Type.h =================================================================== --- /usr/src/contrib/llvm/tools/clang/include/clang/AST/Type.h (revision 292858) +++ /usr/src/contrib/llvm/tools/clang/include/clang/AST/Type.h (working copy) @@ -14,6 +14,8 @@ #ifndef LLVM_CLANG_AST_TYPE_H #define LLVM_CLANG_AST_TYPE_H +#include <cstddef> // for std::max_align_t + #include "clang/AST/NestedNameSpecifier.h" #include "clang/AST/TemplateName.h" #include "clang/Basic/AddressSpaces.h" @@ -4336,7 +4338,7 @@ /// DependentTemplateSpecializationType - Represents a template /// specialization type whose template cannot be resolved, e.g. /// A<T>::template B<T> -class DependentTemplateSpecializationType : +class alignas(alignof(std::max_align_t)) DependentTemplateSpecializationType : public TypeWithKeyword, public llvm::FoldingSetNode { /// \brief The nested name specifier containing the qualifier. alignof(TemplateArgument) is not used because Types.h is used in contexts where TemplateArgument is an incomplete type and the notation would be rejected. The command that built a Type.o that worked was (from the script log of the build): --- Type.o --- /usr/bin/clang++ -target armv6--freebsd11.0-gnueabi -march=armv7a -mno-unaligned-access -target armv6-gnueabi-freebsd11.0 --sysroot=/usr/obj/clang/arm.armv6/usr/src/tmp -B/usr/local/arm-gnueabi-freebs d/bin/ --sysroot=/usr/obj/clang/arm.armv6/usr/src/tmp -B/usr/local/arm-gnueabi-freebsd/bin/ -O -pipe -mfloat-abi=softfp -I/usr/src/lib/clang/libclangast/../../../contrib/llvm/include -I/usr/src/lib/c lang/libclangast/../../../contrib/llvm/tools/clang/include -I/usr/src/lib/clang/libclangast/../../../contrib/llvm/tools/clang/lib/AST -I. -I/usr/src/lib/clang/libclangast/../../../contrib/llvm/../../l ib/clang/include -DLLVM_ON_UNIX -DLLVM_ON_FREEBSD -D__STDC_LIMIT_MACROS -D__STDC_CONSTANT_MACROS -DCLANG_ENABLE_ARCMT -DCLANG_ENABLE_STATIC_ANALYZER -fno-strict-aliasing -DLLVM_DEFAULT_TARGET_TRIPLE=\ "armv6-gnueabi-freebsd11.0\" -DLLVM_HOST_TRIPLE=\"armv6-unknown-freebsd11.0\" -DDEFAULT_SYSROOT=\"\" -MD -MP -MF.depend.Type.o -MTType.o -Qunused-arguments -std=c++11 -fno-exceptions -fno-rtti -stdli b=libc++ -Wno-c++11-extensions -c /usr/src/lib/clang/libclangast/../../../contrib/llvm/tools/clang/lib/AST/Type.cpp -o Type.o So it used (in order): -target armv6--freebsd11.0-gnueabi -march=armv7a -mno-unaligned-access -target armv6-gnueabi-freebsd11.0 (The first -target is what I supplied, the 2nd is from the FreeBSD build environment.) STILL FAILS OVERALL HOWEVER. . . Unfortunately clang++ on the rpi2 with SCTLR bit[1]==1 dies for other c++ syntax when trying to build part of llvm (early in FreeBSD's buildworld): Program terminated with signal 10, Bus error. #0 0x00c43d28 in clang::ASTTemplateArgumentListInfo::initializeFrom () [New Thread 22a18000 (LWP 100079/<unknown>)] (gdb) bt #0 0x00c43d28 in clang::ASTTemplateArgumentListInfo::initializeFrom () #1 0x00c43f10 in clang::ASTTemplateKWAndArgsInfo::initializeFrom () #2 0x00cdc788 in clang::CXXDependentScopeMemberExpr::CXXDependentScopeMemberExpr () #3 0x00cdc99c in clang::CXXDependentScopeMemberExpr::Create () #4 0x00685384 in clang::Sema::ActOnDependentMemberExpr () #5 0x0068abec in clang::Sema::ActOnMemberAccessExpr () #6 0x0044a938 in clang::Parser::ParsePostfixExpressionSuffix () #7 0x00000000 in ?? () (gdb) x/i 0x00c43d28 0xc43d28 <_ZN5clang27ASTTemplateArgumentListInfo14initializeFromERKNS_24TemplateArgumentListInfoERbS4_S4_+396>: vst1.64 {d16-d17}, [r0]! (gdb) info all-regsisters Undefined info command: "all-regsisters". Try "help info". (gdb) info all-registers r0 0x234b96dc 592156380 . . . There are lots of places using "this + 1" and reinterpret_cast that therefore have the potential for a mis-matched alignment between the two types involved, just like the one I initially reported (some of the below might not be at risk, I've not inspected all the details of each): # grep "reinterpret_cast.*this" lib/*/* lib/AST/Decl.cpp: SourceLocation *StoredLocs = reinterpret_cast<SourceLocation *>(this + 1); lib/AST/Decl.cpp: *reinterpret_cast<SourceLocation *>(this + 1) = EndLoc; lib/AST/Decl.cpp: = reinterpret_cast<const SourceLocation *>(this + 1); lib/AST/Decl.cpp: *reinterpret_cast<const SourceLocation *>(this + 1)); lib/AST/DeclCXX.cpp: VarDecl **MyIndices = reinterpret_cast<VarDecl **> (this + 1); lib/AST/DeclOpenMP.cpp: Expr **Vars = reinterpret_cast<Expr **>(this + 1); lib/AST/DeclTemplate.cpp: void **TypesAndInfos = reinterpret_cast<void **>(this + 1); lib/AST/DeclTemplate.cpp: std::memcpy(reinterpret_cast<void*>(this + 1), Expansions, lib/AST/Expr.cpp: return reinterpret_cast<CXXBaseSpecifier**>(static_cast<Type*>(this)+1); lib/AST/Expr.cpp: Stmt *const *SubExprs = reinterpret_cast<Stmt *const *>(this + 1); lib/AST/Expr.cpp: Stmt *const *SubExprs = reinterpret_cast<Stmt *const *>(this + 1); lib/AST/Expr.cpp: Stmt *const *SubExprs = reinterpret_cast<Stmt *const *>(this + 1); lib/AST/Expr.cpp: begin = reinterpret_cast<Stmt **>(this + 1); lib/AST/ExprCXX.cpp: Stmt **StoredArgs = reinterpret_cast<Stmt **>(this + 1); lib/AST/ExprCXX.cpp: reinterpret_cast<Decl**>(this+1)); lib/AST/Stmt.cpp: Stmt **Stmts = reinterpret_cast<Stmt **>(this + 1); lib/AST/Stmt.cpp: reinterpret_cast<char *>(const_cast<CapturedStmt *>(this)) lib/AST/Type.cpp: QualType *argSlot = reinterpret_cast<QualType*>(this+1); lib/AST/Type.cpp: = reinterpret_cast<TemplateArgument *>(this + 1); lib/AST/Type.cpp: TemplateArgument *Begin = reinterpret_cast<TemplateArgument *>(this + 1); lib/Basic/IdentifierTable.cpp: IdentifierInfo **KeyInfo = reinterpret_cast<IdentifierInfo **>(this+1); lib/Basic/IdentifierTable.cpp: return reinterpret_cast<keyword_iterator>(this+1); lib/CodeGen/CGCleanup.h: return reinterpret_cast<Handler*>(this+1); lib/CodeGen/CGCleanup.h: return reinterpret_cast<const Handler*>(this+1); lib/CodeGen/CGCleanup.h: return reinterpret_cast<llvm::Value**>(this+1); lib/CodeGen/CGCleanup.h: return reinterpret_cast<llvm::Value* const *>(this+1); lib/CodeGen/CGExprCXX.cpp: RValue *getPlacementArgs() { return reinterpret_cast<RValue*>(this+1); } lib/CodeGen/CGExprCXX.cpp: return reinterpret_cast<DominatingValue<RValue>::saved_type*>(this+1); lib/Sema/CodeCompleteConsumer.cpp: Chunk *StoredChunks = reinterpret_cast<Chunk *>(this + 1); But there is lots more use of reinterpret_cast where "this" is not involved that might also have problems. Compare: # grep -l "reinterpret_cast.*this" lib/*/* lib/AST/Decl.cpp lib/AST/DeclCXX.cpp lib/AST/DeclOpenMP.cpp lib/AST/DeclTemplate.cpp lib/AST/Expr.cpp lib/AST/ExprCXX.cpp lib/AST/Stmt.cpp lib/AST/Type.cpp lib/Basic/IdentifierTable.cpp lib/CodeGen/CGCleanup.h lib/CodeGen/CGExprCXX.cpp lib/Sema/CodeCompleteConsumer.cpp vs. # grep -l "reinterpret_cast" lib/*/* lib/AST/APValue.cpp lib/AST/ASTDiagnostic.cpp lib/AST/Decl.cpp lib/AST/DeclCXX.cpp lib/AST/DeclOpenMP.cpp lib/AST/DeclTemplate.cpp lib/AST/DeclarationName.cpp lib/AST/Expr.cpp lib/AST/ExprCXX.cpp lib/AST/ExprConstant.cpp lib/AST/ItaniumMangle.cpp lib/AST/NestedNameSpecifier.cpp lib/AST/ParentMap.cpp lib/AST/Stmt.cpp lib/AST/StmtIterator.cpp lib/AST/Type.cpp lib/AST/TypeLoc.cpp lib/Analysis/CFG.cpp lib/Basic/Diagnostic.cpp lib/Basic/FileManager.cpp lib/Basic/IdentifierTable.cpp lib/CodeGen/CGBlocks.h lib/CodeGen/CGCleanup.cpp lib/CodeGen/CGCleanup.h lib/CodeGen/CGExpr.cpp lib/CodeGen/CGExprCXX.cpp lib/CodeGen/CodeGenModule.cpp lib/CodeGen/MicrosoftCXXABI.cpp lib/Driver/MSVCToolChain.cpp lib/Driver/Tools.h lib/Format/Encoding.h lib/Frontend/CacheTokens.cpp lib/Frontend/DependencyFile.cpp lib/Frontend/TextDiagnostic.cpp lib/Lex/HeaderMap.cpp lib/Lex/LiteralSupport.cpp lib/Parse/ParseExpr.cpp lib/Parse/ParseExprCXX.cpp lib/Parse/ParseObjc.cpp lib/Parse/ParsePragma.cpp lib/Parse/ParseTentative.cpp lib/Parse/Parser.cpp lib/Rewrite/RewriteRope.cpp lib/Sema/CodeCompleteConsumer.cpp lib/Sema/IdentifierResolver.cpp lib/Sema/SemaCast.cpp lib/Sema/SemaCodeComplete.cpp lib/Sema/SemaDecl.cpp lib/Sema/SemaDeclCXX.cpp lib/Sema/SemaDeclObjC.cpp lib/Sema/SemaExprMember.cpp lib/Sema/SemaExprObjC.cpp lib/Sema/SemaInit.cpp lib/Sema/SemaLookup.cpp lib/Sema/SemaStmt.cpp lib/Sema/SemaStmtAsm.cpp lib/Sema/TreeTransform.h lib/Serialization/ASTReader.cpp lib/Serialization/ASTReaderDecl.cpp lib/Serialization/ASTReaderStmt.cpp lib/Serialization/ASTWriter.cpp -- You are receiving this mail because: You are the assignee for the bug.
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