https://github.com/macurtis-amd created
https://github.com/llvm/llvm-project/pull/134621
When passing `-save-temps` to clang, the generated preprocessed output uses gnu
line markers. This unexpectedly triggers gnu-line-marker warnings when used
with `-Weverything` or `-pedantic`. Even worse, compilation fails if `-Werror`
is used.
This change suppresses gnu-line-marker warnings when invoking clang with input
from a preprocessor job and the user has not otherwise explictly specified
`-Wgnu-line-marker` somewhere on the command line. Note that this does apply to
user provided preprocessed files.
fixes #63802
>From eeab645707eea54d378fe6e747a24b161d85ef13 Mon Sep 17 00:00:00 2001
From: Matthew Curtis <macur...@amd.com>
Date: Sat, 5 Apr 2025 04:34:03 -0500
Subject: [PATCH] [clang][driver] Suppress gnu-line-marker when saving temps
When passing `-save-temps` to clang, the generated preprocessed output uses gnu
line markers. This unexpectedly triggers gnu-line-marker warnings when used with
`-Weverything` or `-pedantic`. Even worse, compilation fails if `-Werror` is
used.
This change suppresses gnu-line-marker warnings when invoking clang with input
from a preprocessor job and the user has not otherwise explictly specified
`-Wgnu-line-marker` somewhere on the command line. Note that this does apply to
user provided preprocessed files.
fixes #63802
---
clang/lib/Driver/ToolChains/Clang.cpp | 27 +++++++++++++++++++++++++++
clang/test/Driver/save-temps.c | 16 ++++++++++++++++
2 files changed, 43 insertions(+)
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp
b/clang/lib/Driver/ToolChains/Clang.cpp
index 70489adf01c94..36cfcecbabe98 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -28,6 +28,7 @@
#include "clang/Basic/CLWarnings.h"
#include "clang/Basic/CharInfo.h"
#include "clang/Basic/CodeGenOptions.h"
+#include "clang/Basic/DiagnosticLex.h"
#include "clang/Basic/HeaderInclude.h"
#include "clang/Basic/LangOptions.h"
#include "clang/Basic/MakeSupport.h"
@@ -67,6 +68,8 @@
#include "llvm/TargetParser/RISCVTargetParser.h"
#include <cctype>
+#include "/home/macurtis/mcc/src/MCC-PRINT.h"
+
using namespace clang::driver;
using namespace clang::driver::tools;
using namespace clang;
@@ -5077,6 +5080,7 @@ void Clang::ConstructJob(Compilation &C, const JobAction
&JA,
const InputInfo &Input =
IsExtractAPI ? ExtractAPIPlaceholderInput : Inputs[0];
+ bool hasPreprocessorJobInput = false;
InputInfoList ExtractAPIInputs;
InputInfoList HostOffloadingInputs;
const InputInfo *CudaDeviceInput = nullptr;
@@ -5101,6 +5105,8 @@ void Clang::ConstructJob(Compilation &C, const JobAction
&JA,
} else {
llvm_unreachable("unexpectedly given multiple inputs");
}
+ hasPreprocessorJobInput |=
+ I.getAction()->getKind() == Action::PreprocessJobClass;
}
const llvm::Triple *AuxTriple =
@@ -6506,6 +6512,27 @@ void Clang::ConstructJob(Compilation &C, const JobAction
&JA,
Args.AddLastArg(CmdArgs, options::OPT_pedantic_errors);
Args.AddLastArg(CmdArgs, options::OPT_w);
+ // Possibly suppress gnu-line-marker diagnostics. This suppresses spurious
+ // warnings or errors when using '-save-temps' with, for example, '-Werror
+ // -Weverything' or '-pedantic'.
+ if (hasPreprocessorJobInput &&
+ !D.getDiags().isIgnored(diag::ext_pp_gnu_line_directive,
+ SourceLocation())) {
+ auto IDs = D.getDiags().getDiagnosticIDs();
+ StringRef gnuLineMarker =
+ IDs->getWarningOptionForDiag(diag::ext_pp_gnu_line_directive);
+
+ // If for some reason the user has explicitly specified -Wgnu-line-marker,
+ // they are on their own.
+ bool hasGnuLineMarker = false;
+ for (std::string &V : Args.getAllArgValues(options::OPT_W_Joined)) {
+ if ((hasGnuLineMarker = V == gnuLineMarker))
+ break;
+ }
+ if (!hasGnuLineMarker)
+ CmdArgs.push_back(Args.MakeArgString("-Wno-" + gnuLineMarker));
+ }
+
Args.addOptInFlag(CmdArgs, options::OPT_ffixed_point,
options::OPT_fno_fixed_point);
diff --git a/clang/test/Driver/save-temps.c b/clang/test/Driver/save-temps.c
index b0cfa4fd814a8..48a590700076e 100644
--- a/clang/test/Driver/save-temps.c
+++ b/clang/test/Driver/save-temps.c
@@ -90,3 +90,19 @@
// CHECK-SAVE-TEMPS-CMSE: -cc1as
// CHECK-SAVE-TEMPS-CMSE: +8msecext
// CHECK-SAVE-TEMPS-CMSE-NOT: '+cmse' is not a recognized feature for this
target (ignoring feature)
+
+// RUN: %clang -target x86_64-unknown-linux-gnu -Werror -pedantic -save-temps
%s -### 2>&1 \
+// RUN: | FileCheck %s -check-prefix=CHECK-SAVE-TEMPS-GLM-000
+// CHECK-SAVE-TEMPS-GLM-000: "-o" "save-temps.i"
+// CHECK-SAVE-TEMPS-GLM-000: "-pedantic" "-Wno-gnu-line-marker"{{.*}} "-x"
"cpp-output" "save-temps.i"
+
+// RUN: %clang -target x86_64-unknown-linux-gnu -Werror -Weverything
-save-temps %s -### 2>&1 \
+// RUN: | FileCheck %s -check-prefix=CHECK-SAVE-TEMPS-GLM-001
+// CHECK-SAVE-TEMPS-GLM-001: "-o" "save-temps.i"
+// CHECK-SAVE-TEMPS-GLM-001: "-Weverything" "-Wno-gnu-line-marker"{{.*}} "-x"
"cpp-output" "save-temps.i"
+
+// RUN: %clang -target x86_64-unknown-linux-gnu -Werror -Weverything
-Wgnu-line-marker -save-temps %s -### 2>&1 \
+// RUN: | FileCheck %s -check-prefix=CHECK-SAVE-TEMPS-GLM-002
+// RUN: %clang -target x86_64-unknown-linux-gnu -Werror -Weverything
-save-temps -x cpp-output %s -### 2>&1 \
+// RUN: | FileCheck %s -check-prefix=CHECK-SAVE-TEMPS-GLM-002
+// CHECK-SAVE-TEMPS-GLM-002-NOT: "-Wno-gnu-line-marker"
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