Author: Anutosh Bhat Date: 2025-12-08T22:23:54+05:30 New Revision: cbce30e0f862099758c4f375cc35fb214fb1b513
URL: https://github.com/llvm/llvm-project/commit/cbce30e0f862099758c4f375cc35fb214fb1b513 DIFF: https://github.com/llvm/llvm-project/commit/cbce30e0f862099758c4f375cc35fb214fb1b513.diff LOG: [clang-repl] Skip CodeGen for top-level decls when diagnostics report errors (#169989) We can see the following while running clang-repl in C mode ``` anutosh491@vv-nuc:/build/anutosh491/llvm-project/build/bin$ ./clang-repl --Xcc=-x --Xcc=c --Xcc=-std=c23 clang-repl> printf("hi\n"); In file included from <<< inputs >>>:1: input_line_1:1:1: error: call to undeclared library function 'printf' with type 'int (const char *, ...)'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration] 1 | printf("hi\n"); | ^ input_line_1:1:1: note: include the header <stdio.h> or explicitly provide a declaration for 'printf' error: Parsing failed. clang-repl> #include <stdio.h> hi ``` In debug mode while dumping the generated Module, i see this ``` clang-repl> printf("hi\n"); In file included from <<< inputs >>>:1: input_line_1:1:1: error: call to undeclared library function 'printf' with type 'int (const char *, ...)'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration] 1 | printf("hi\n"); | ^ input_line_1:1:1: note: include the header <stdio.h> or explicitly provide a declaration for 'printf' error: Parsing failed. clang-repl> #include <stdio.h> === compile-ptu 1 === [TU=0x55556cfbf830, M=0x55556cfc13a0 (incr_module_1)] [LLVM IR] ; ModuleID = 'incr_module_1' source_filename = "incr_module_1" target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128" target triple = "x86_64-unknown-linux-gnu" @.str = private unnamed_addr constant [4 x i8] c"hi\0A\00", align 1 @llvm.global_ctors = appending global [1 x { i32, ptr, ptr }] [{ i32, ptr, ptr } { i32 65535, ptr @_GLOBAL__sub_I_incr_module_1, ptr null }] define internal void @__stmts__0() #0 { entry: %call = call i32 (ptr, ...) @printf(ptr noundef @.str) ret void } declare i32 @printf(ptr noundef, ...) #1 ; Function Attrs: noinline nounwind uwtable define internal void @_GLOBAL__sub_I_incr_module_1() #2 section ".text.startup" { entry: call void @__stmts__0() ret void } attributes #0 = { "min-legal-vector-width"="0" } attributes #1 = { "frame-pointer"="all" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" } attributes #2 = { noinline nounwind uwtable "frame-pointer"="all" "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" } !llvm.module.flags = !{!0, !1, !2, !3, !4} !llvm.ident = !{!5} !0 = !{i32 1, !"wchar_size", i32 4} !1 = !{i32 8, !"PIC Level", i32 2} !2 = !{i32 7, !"PIE Level", i32 2} !3 = !{i32 7, !"uwtable", i32 2} !4 = !{i32 7, !"frame-pointer", i32 2} !5 = !{!"clang version 22.0.0git (https://github.com/anutosh491/llvm-project.git 81ad8fbc2bb09bae61ed59316468011e4a42cf47)"} === end compile-ptu === execute-ptu 1: [TU=0x55556cfbf830, M=0x55556cfc13a0 (incr_module_1)] hi ``` Basically I see that CodeGen emits IR for a cell before we know whether DiagnosticsEngine has an error. For C code like `printf("hi\n");` without <stdio.h>, Sema emits a diagnostic but still produces a "codegen-able" `TopLevelStmt`, so the `printf` call is IR-generated into the current module. Previously, when `Diags.hasErrorOccurred()` was true, we only cleaned up the PTU AST and left the CodeGen module untouched. The next successful cell then called `GenModule()`, which returned that same module (now also containing the next cell’s IR), causing side effects from the failed cell (e.g. printf) Added: Modified: clang/lib/Interpreter/IncrementalAction.cpp clang/test/Interpreter/pretty-print.c Removed: ################################################################################ diff --git a/clang/lib/Interpreter/IncrementalAction.cpp b/clang/lib/Interpreter/IncrementalAction.cpp index 3d489fce54bc6..d22031c8fa893 100644 --- a/clang/lib/Interpreter/IncrementalAction.cpp +++ b/clang/lib/Interpreter/IncrementalAction.cpp @@ -135,6 +135,11 @@ bool InProcessPrintingASTConsumer::HandleTopLevelDecl(DeclGroupRef DGR) { if (DGR.isNull()) return true; + CompilerInstance *CI = Interp.getCompilerInstance(); + DiagnosticsEngine &Diags = CI->getDiagnostics(); + if (Diags.hasErrorOccurred()) + return true; + for (Decl *D : DGR) if (auto *TLSD = llvm::dyn_cast<TopLevelStmtDecl>(D)) if (TLSD && TLSD->isSemiMissing()) { diff --git a/clang/test/Interpreter/pretty-print.c b/clang/test/Interpreter/pretty-print.c index 9a7bf752238ab..b8058a762897e 100644 --- a/clang/test/Interpreter/pretty-print.c +++ b/clang/test/Interpreter/pretty-print.c @@ -20,6 +20,9 @@ const char* c_null_str = 0; c_null_str "Hello, world" // CHECK-NEXT: ({{(const )?}}char[13]) "Hello, world" +printf("Hello World\n"); +// expected-error {{call to undeclared library function 'printf' with type 'int (const char *, ...)' }} + int x = 42; x // CHECK-NEXT: (int) 42 _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
