Author: Aaron Ballman Date: 2022-03-24T10:39:14-04:00 New Revision: 488c772920566354075f7933eedbe4358c128bd2
URL: https://github.com/llvm/llvm-project/commit/488c772920566354075f7933eedbe4358c128bd2 DIFF: https://github.com/llvm/llvm-project/commit/488c772920566354075f7933eedbe4358c128bd2.diff LOG: Fix a crash with variably-modified parameter types in a naked function Naked functions have no prolog, so it's not valid to emit prolog code to evaluate the variably-modified type. This fixes Issue 50541. Added: Modified: clang/docs/ReleaseNotes.rst clang/lib/CodeGen/CodeGenFunction.cpp clang/test/CodeGen/attr-naked.c Removed: ################################################################################ diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index 373d4156cd797..720fff759c4ec 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -72,10 +72,12 @@ Bug Fixes - Previously invalid member variables with template parameters would crash clang. Now fixed by setting identifiers for them. This fixes `Issue 28475 (PR28101) <https://github.com/llvm/llvm-project/issues/28475>`_. - - Now allow the `restrict` and `_Atomic` qualifiers to be used in conjunction with `__auto_type` to match the behavior in GCC. This fixes `Issue 53652 <https://github.com/llvm/llvm-project/issues/53652>`_. +- No longer crash when specifying a variably-modified parameter type in a + function with the ``naked`` attribute. This fixes + `Issue 50541 <https://github.com/llvm/llvm-project/issues/50541>`_. Improvements to Clang's diagnostics diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp index de717439918d7..15719d12eafeb 100644 --- a/clang/lib/CodeGen/CodeGenFunction.cpp +++ b/clang/lib/CodeGen/CodeGenFunction.cpp @@ -1195,27 +1195,26 @@ void CodeGenFunction::StartFunction(GlobalDecl GD, QualType RetTy, } // If any of the arguments have a variably modified type, make sure to - // emit the type size. - for (FunctionArgList::const_iterator i = Args.begin(), e = Args.end(); - i != e; ++i) { - const VarDecl *VD = *i; - - // Dig out the type as written from ParmVarDecls; it's unclear whether - // the standard (C99 6.9.1p10) requires this, but we're following the - // precedent set by gcc. - QualType Ty; - if (const ParmVarDecl *PVD = dyn_cast<ParmVarDecl>(VD)) - Ty = PVD->getOriginalType(); - else - Ty = VD->getType(); + // emit the type size, but only if the function is not naked. Naked functions + // have no prolog to run this evaluation. + if (!FD || !FD->hasAttr<NakedAttr>()) { + for (const VarDecl *VD : Args) { + // Dig out the type as written from ParmVarDecls; it's unclear whether + // the standard (C99 6.9.1p10) requires this, but we're following the + // precedent set by gcc. + QualType Ty; + if (const ParmVarDecl *PVD = dyn_cast<ParmVarDecl>(VD)) + Ty = PVD->getOriginalType(); + else + Ty = VD->getType(); - if (Ty->isVariablyModifiedType()) - EmitVariablyModifiedType(Ty); + if (Ty->isVariablyModifiedType()) + EmitVariablyModifiedType(Ty); + } } // Emit a location at the end of the prologue. if (CGDebugInfo *DI = getDebugInfo()) DI->EmitLocation(Builder, StartLoc); - // TODO: Do we need to handle this in two places like we do with // target-features/target-cpu? if (CurFuncDecl) diff --git a/clang/test/CodeGen/attr-naked.c b/clang/test/CodeGen/attr-naked.c index 2bd9e4c77c025..b4da372247929 100644 --- a/clang/test/CodeGen/attr-naked.c +++ b/clang/test/CodeGen/attr-naked.c @@ -23,5 +23,13 @@ __attribute((naked)) void t3(int x) { // CHECK: unreachable } +// Make sure naked functions do not attempt to evaluate parameters with a +// variably-modified type. Naked functions get no prolog, so this evaluation +// should not take place. +__attribute__((naked)) void t4(int len, char x[len]) { + // CHECK: define{{.*}} void @t4(i32 noundef{{.*}}, i8* noundef{{.*}}) + // CHECK: unreachable +} + // CHECK: attributes [[NAKED_OPTNONE]] = { naked noinline nounwind optnone{{.*}} } // CHECK: attributes [[NAKED]] = { naked noinline nounwind{{.*}} } _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
