Author: hans Date: Tue Oct 7 20:58:02 2014 New Revision: 219272 URL: http://llvm.org/viewvc/llvm-project?rev=219272&view=rev Log: Disallow using function parameters in extended asm inputs or outputs in naked functions (PR21178)
Clang won't emit any prologues for such functions, so it would assert trying to codegen the parameter references. This patch makes Clang check the extended asm inputs and outputs for references to function parameters. Differential Revision: http://reviews.llvm.org/D5640 Modified: cfe/trunk/lib/Sema/SemaStmtAsm.cpp cfe/trunk/test/Sema/attr-naked.c Modified: cfe/trunk/lib/Sema/SemaStmtAsm.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaStmtAsm.cpp?rev=219272&r1=219271&r2=219272&view=diff ============================================================================== --- cfe/trunk/lib/Sema/SemaStmtAsm.cpp (original) +++ cfe/trunk/lib/Sema/SemaStmtAsm.cpp Tue Oct 7 20:58:02 2014 @@ -75,6 +75,32 @@ static bool isOperandMentioned(unsigned return false; } +static bool CheckNakedParmReference(Expr *E, Sema &S) { + FunctionDecl *Func = dyn_cast<FunctionDecl>(S.CurContext); + if (!Func) + return false; + if (!Func->hasAttr<NakedAttr>()) + return false; + + SmallVector<Expr*, 4> WorkList; + WorkList.push_back(E); + while (WorkList.size()) { + Expr *E = WorkList.pop_back_val(); + if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) { + if (isa<ParmVarDecl>(DRE->getDecl())) { + S.Diag(DRE->getLocStart(), diag::err_asm_naked_parm_ref); + S.Diag(Func->getAttr<NakedAttr>()->getLocation(), diag::note_attribute); + return true; + } + } + for (Stmt *Child : E->children()) { + if (Expr *E = dyn_cast_or_null<Expr>(Child)) + WorkList.push_back(E); + } + } + return false; +} + StmtResult Sema::ActOnGCCAsmStmt(SourceLocation AsmLoc, bool IsSimple, bool IsVolatile, unsigned NumOutputs, unsigned NumInputs, IdentifierInfo **Names, @@ -117,6 +143,10 @@ StmtResult Sema::ActOnGCCAsmStmt(SourceL diag::err_asm_invalid_lvalue_in_output) << OutputExpr->getSourceRange()); + // Referring to parameters is not allowed in naked functions. + if (CheckNakedParmReference(OutputExpr, *this)) + return StmtError(); + if (RequireCompleteType(OutputExpr->getLocStart(), Exprs[i]->getType(), diag::err_dereference_incomplete_type)) return StmtError(); @@ -160,6 +190,10 @@ StmtResult Sema::ActOnGCCAsmStmt(SourceL Expr *InputExpr = Exprs[i]; + // Referring to parameters is not allowed in naked functions. + if (CheckNakedParmReference(InputExpr, *this)) + return StmtError(); + // Only allow void types for memory constraints. if (Info.allowsMemory() && !Info.allowsRegister()) { if (CheckAsmLValue(InputExpr, *this)) @@ -421,17 +455,8 @@ ExprResult Sema::LookupInlineAsmIdentifi if (!Result.isUsable()) return Result; // Referring to parameters is not allowed in naked functions. - if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Result.get())) { - if (ParmVarDecl *Parm = dyn_cast<ParmVarDecl>(DRE->getDecl())) { - if (FunctionDecl *Func = dyn_cast<FunctionDecl>(Parm->getDeclContext())) { - if (Func->hasAttr<NakedAttr>()) { - Diag(Id.getLocStart(), diag::err_asm_naked_parm_ref); - Diag(Func->getAttr<NakedAttr>()->getLocation(), diag::note_attribute); - return ExprError(); - } - } - } - } + if (CheckNakedParmReference(Result.get(), *this)) + return ExprError(); QualType T = Result.get()->getType(); Modified: cfe/trunk/test/Sema/attr-naked.c URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/attr-naked.c?rev=219272&r1=219271&r2=219272&view=diff ============================================================================== --- cfe/trunk/test/Sema/attr-naked.c (original) +++ cfe/trunk/test/Sema/attr-naked.c Tue Oct 7 20:58:02 2014 @@ -32,3 +32,19 @@ __attribute__((naked)) void t7() { asm("movl $42, %eax"); ; } + +extern int x, y; + +__attribute__((naked)) void t8(int z) { // expected-note{{attribute is here}} + __asm__ ("movl $42, %1" + : "=r"(x), + "=r"(z) // expected-error{{parameter references not allowed in naked functions}} + ); +} + +__attribute__((naked)) void t9(int z) { // expected-note{{attribute is here}} + __asm__ ("movl %eax, %1" + : : "r"(x), + "r"(z) // expected-error{{parameter references not allowed in naked functions}} + ); +} _______________________________________________ cfe-commits mailing list [email protected] http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
