[clang] e74a7a9 - cc1: Report an error for multiple actions unless separated by -main-file-name (#91140)
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Tue May 7 09:15:56 PDT 2024
Author: Fangrui Song
Date: 2024-05-07T09:15:52-07:00
New Revision: e74a7a9fd79a74073277471243a44527c71eb4a9
URL: https://github.com/llvm/llvm-project/commit/e74a7a9fd79a74073277471243a44527c71eb4a9
DIFF: https://github.com/llvm/llvm-project/commit/e74a7a9fd79a74073277471243a44527c71eb4a9.diff
LOG: cc1: Report an error for multiple actions unless separated by -main-file-name (#91140)
When multiple actions are specified, the last one is used and others are
overridden. This might lead to confusion if the user is used to driver's
`-S -emit-llvm` behavior.
```
%clang_cc1 -S -emit-llvm a.c # -S is overridden
%clang_cc1 -emit-llvm -S a.c # -emit-llvm is overridden
%clang_cc1 -fsyntax-only -S a.c # -fsyntax-only is overridden
```
However, we want to continue supporting overriding the driver action
with -Xclang:
* `clang -c -Xclang -ast-dump a.c` (`%clang -cc1 -emit-obj ...
-main-file-name a.c ... -ast-dump`)
* `clang -c -xc++ -Xclang -emit-module stl.modulemap`
As an exception, we allow -ast-dump* options to be composed together
(e.g. `-ast-dump -ast-dump-lookups` in AST/ast-dump-lookups.cpp).
Added:
clang/test/Frontend/multiple-actions.c
Modified:
clang/include/clang/Basic/DiagnosticFrontendKinds.td
clang/lib/Frontend/CompilerInvocation.cpp
Removed:
################################################################################
diff --git a/clang/include/clang/Basic/DiagnosticFrontendKinds.td b/clang/include/clang/Basic/DiagnosticFrontendKinds.td
index fcffadacc8e631..e456ec2cac461c 100644
--- a/clang/include/clang/Basic/DiagnosticFrontendKinds.td
+++ b/clang/include/clang/Basic/DiagnosticFrontendKinds.td
@@ -134,6 +134,8 @@ def err_fe_no_pch_in_dir : Error<
"no suitable precompiled header file found in directory '%0'">;
def err_fe_action_not_available : Error<
"action %0 not compiled in">;
+def err_fe_invalid_multiple_actions : Error<
+ "'%0' action ignored; '%1' action specified previously">;
def err_fe_invalid_alignment : Error<
"invalid value '%1' in '%0'; alignment must be a power of 2">;
def err_fe_invalid_exception_model
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 8312abc3603953..948fe08c863a66 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -2841,6 +2841,30 @@ static bool ParseFrontendArgs(FrontendOptions &Opts, ArgList &Args,
}
Opts.ProgramAction = *ProgramAction;
+
+ // Catch common mistakes when multiple actions are specified for cc1 (e.g.
+ // -S -emit-llvm means -emit-llvm while -emit-llvm -S means -S). However, to
+ // support driver `-c -Xclang ACTION` (-cc1 -emit-llvm file -main-file-name
+ // X ACTION), we suppress the error when the two actions are separated by
+ // -main-file-name.
+ //
+ // As an exception, accept composable -ast-dump*.
+ if (!A->getSpelling().starts_with("-ast-dump")) {
+ const Arg *SavedAction = nullptr;
+ for (const Arg *AA :
+ Args.filtered(OPT_Action_Group, OPT_main_file_name)) {
+ if (AA->getOption().matches(OPT_main_file_name)) {
+ SavedAction = nullptr;
+ } else if (!SavedAction) {
+ SavedAction = AA;
+ } else {
+ if (!A->getOption().matches(OPT_ast_dump_EQ))
+ Diags.Report(diag::err_fe_invalid_multiple_actions)
+ << SavedAction->getSpelling() << A->getSpelling();
+ break;
+ }
+ }
+ }
}
if (const Arg* A = Args.getLastArg(OPT_plugin)) {
diff --git a/clang/test/Frontend/multiple-actions.c b/clang/test/Frontend/multiple-actions.c
new file mode 100644
index 00000000000000..284e8f0467bfe1
--- /dev/null
+++ b/clang/test/Frontend/multiple-actions.c
@@ -0,0 +1,7 @@
+// RUN: not %clang_cc1 -S -emit-llvm -main-file-name %s 2>&1 | FileCheck %s --check-prefix=ERR1 --implicit-check-not=error:
+// ERR1: error: '-S' action ignored; '-emit-llvm' action specified previously
+
+// RUN: not %clang_cc1 -main-file-name %s -emit-llvm-only -emit-llvm -S 2>&1 | FileCheck %s --check-prefix=ERR2 --implicit-check-not=error:
+// ERR2: error: '-emit-llvm-only' action ignored; '-S' action specified previously
+
+// RUN: %clang_cc1 -S -main-file-name %s -emit-llvm -o /dev/null
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