From: Eduard Zingerman Date: Fri, 28 Oct 2022 14:59:08 +0000 (-0700) Subject: [clang][DebugInfo] Emit DISubprogram for extern functions with reserved names X-Git-Tag: upstream/17.0.6~29189 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=524c640090a8463305acbafd7606f1db3c1256e2;p=platform%2Fupstream%2Fllvm.git [clang][DebugInfo] Emit DISubprogram for extern functions with reserved names Callsite `DISubprogram` entries are not generated for: - builtin functions; - external functions with reserved names (e.g. names starting from "__"). This limitation was added by the commit [1] as a workaround for the situation described in [2] that triggered the IR verifier error. The goal of the present commit is to lift this limitation by adjusting the IR verifier logic. The logic behind [1] is to avoid the following situation: - a `DISubprogram` is added for some builtin function; - there is some location where this builtin is also emitted by a transformation (w/o debug location); - the `Verifier::visitCallBase` sees a call to a function with `DISubprogram` but w/o debug location and emits an error. Here is an updated example of such situation taken from [2]: ``` extern "C" int memcmp(void *, void *, long); struct a { int b; int c; int d; }; struct e { int f[1000]; }; bool foo(e g, e &h) { // DISubprogram for memcmp is created here when [1] is commented out return memcmp(&g, &h, sizeof(e)); } bool bar(a &g, a &h) { // memcmp might be generated here by MergeICmps return g.b == h.b && g.c == h.c && g.d == h.d; } ``` This triggers the verifier error when: - compiled for AArch64: `clang++ -c -g -Oz -target aarch64-unknown-linux-android21 test.cpp`; - [1] check is commented out. Instead of forbidding generation of `DISubprogram` entries as in [1] one can instead adjust the verifier to additionally check if callee has a body. Functions w/o bodies cannot be inlined and thus verifier warning is not necessary. E.g. `llvm::InlineFunction` requires functions for which `GlobalValue::isDeclaration() == false`. [1] 568db780bb7267651a902da8e85bc59fc89aea70 [2] https://bugs.chromium.org/p/chromium/issues/detail?id=1022296 Differential Revision: https://reviews.llvm.org/D136041 --- diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp index aa02821..4b56e15 100644 --- a/clang/lib/CodeGen/CGDebugInfo.cpp +++ b/clang/lib/CodeGen/CGDebugInfo.cpp @@ -4228,17 +4228,11 @@ void CGDebugInfo::EmitFuncDeclForCallSite(llvm::CallBase *CallOrInvoke, if (Func->getSubprogram()) return; - // Do not emit a declaration subprogram for a builtin, a function with nodebug - // attribute, or if call site info isn't required. Also, elide declarations - // for functions with reserved names, as call site-related features aren't - // interesting in this case (& also, the compiler may emit calls to these - // functions without debug locations, which makes the verifier complain). - if (CalleeDecl->getBuiltinID() != 0 || CalleeDecl->hasAttr() || + // Do not emit a declaration subprogram for a function with nodebug + // attribute, or if call site info isn't required. + if (CalleeDecl->hasAttr() || getCallSiteRelatedAttrs() == llvm::DINode::FlagZero) return; - if (CalleeDecl->isReserved(CGM.getLangOpts()) != - ReservedIdentifierStatus::NotReserved) - return; // If there is no DISubprogram attached to the function being called, // create the one describing the function in order to have complete diff --git a/clang/test/CodeGen/debug-info-extern-call.c b/clang/test/CodeGen/debug-info-extern-call.c index fad52d0..0d18dc4 100644 --- a/clang/test/CodeGen/debug-info-extern-call.c +++ b/clang/test/CodeGen/debug-info-extern-call.c @@ -29,8 +29,8 @@ // DECLS-FOR-EXTERN: [[FN1_TYPES]] = !{[[X_TYPE:![0-9]+]], // DECLS-FOR-EXTERN: [[X_TYPE]] = !DIDerivedType(tag: DW_TAG_typedef, name: "x", // DECLS-FOR-EXTERN-SAME: baseType: [[INT_TYPE]]) -// DECLS-FOR-EXTERN-NOT: !DISubprogram(name: "memcmp" -// DECLS-FOR-EXTERN-NOT: !DISubprogram(name: "__some_reserved_name" +// DECLS-FOR-EXTERN: !DISubprogram(name: "memcmp" +// DECLS-FOR-EXTERN: !DISubprogram(name: "__some_reserved_name" // NO-DECLS-FOR-EXTERN-NOT: !DISubprogram(name: "fn1" // NO-DECLS-FOR-EXTERN-NOT: !DISubprogram(name: "memcmp" diff --git a/llvm/lib/IR/Verifier.cpp b/llvm/lib/IR/Verifier.cpp index 06f0316..0614f20 100644 --- a/llvm/lib/IR/Verifier.cpp +++ b/llvm/lib/IR/Verifier.cpp @@ -3468,9 +3468,11 @@ void Verifier::visitCallBase(CallBase &Call) { // Verify that each inlinable callsite of a debug-info-bearing function in a // debug-info-bearing function has a debug location attached to it. Failure to // do so causes assertion failures when the inliner sets up inline scope info - // (Interposable functions are not inlinable). + // (Interposable functions are not inlinable, neither are functions without + // definitions.) if (Call.getFunction()->getSubprogram() && Call.getCalledFunction() && !Call.getCalledFunction()->isInterposable() && + !Call.getCalledFunction()->isDeclaration() && Call.getCalledFunction()->getSubprogram()) CheckDI(Call.getDebugLoc(), "inlinable function call in a function with " diff --git a/llvm/test/Verifier/callsite-dbgloc.ll b/llvm/test/Verifier/callsite-dbgloc.ll index 4fdb55d..fef86f6 100644 --- a/llvm/test/Verifier/callsite-dbgloc.ll +++ b/llvm/test/Verifier/callsite-dbgloc.ll @@ -33,18 +33,24 @@ entry: ret void, !dbg !22 } -declare void @i(...) #1 +declare !dbg !23 void @i(...) #1 ; Function Attrs: nounwind ssp uwtable define void @g() #0 !dbg !11 { entry: ; Manually removed !dbg. ; CHECK: inlinable function call in a function with debug info must have a !dbg location +; CHECK: @h() call void @h() ; CHECK-NOT: inlinable function call in a function with debug info must have a !dbg location +; CHECK-NOT: @j() call void @j() ; CHECK: inlinable function call in a function with debug info must have a !dbg location +; CHECK: @k() call void @k() +; CHECK-NOT: inlinable function call in a function with debug info must have a !dbg location +; CHECK-NOT: @i() + call void (...) @i() ret void, !dbg !13 } @@ -86,3 +92,6 @@ attributes #0 = { nounwind ssp uwtable } !20 = distinct !DISubprogram(name: "k", scope: !1, file: !1, line: 6, type: !8, isLocal: false, isDefinition: true, scopeLine: 6, isOptimized: false, unit: !0, retainedNodes: !2) !21 = !DILocation(line: 4, column: 12, scope: !20) !22 = !DILocation(line: 4, column: 17, scope: !20) +!23 = !DISubprogram(name: "i", scope: !1, file: !1, line: 1, type: !24, flags: DIFlagPrototyped, spFlags: DISPFlagOptimized, retainedNodes: !2) +!24 = !DISubroutineType(types: !25) +!25 = !{null}