Try to shorten system header paths when using -MD depfiles
GCC tries to shorten system headers in depfiles using its real path
(resolving components like ".." and following symlinks). Mimic this
feature to ensure that the Ninja build tool detects the correct
dependencies when a symlink changes directory levels, see
https://github.com/ninja-build/ninja/issues/1330
An option to disable this feature is added in case "these changed header
paths may conflict with some compilation environments", see
https://gcc.gnu.org/ml/gcc-patches/2012-09/msg00287.html
Note that the original feature request for GCC
(https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52974) also included paths
preprocessed output (-E) and diagnostics. That is not implemented now
since I am not sure if it breaks something else.
Differential Revision: https://reviews.llvm.org/D37954
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@316193 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/clang/Driver/Options.td b/include/clang/Driver/Options.td
index 526b72f..c87cac9 100644
--- a/include/clang/Driver/Options.td
+++ b/include/clang/Driver/Options.td
@@ -384,6 +384,11 @@
HelpText<"Specify name of main file output in depfile">;
def MV : Flag<["-"], "MV">, Group<M_Group>, Flags<[CC1Option]>,
HelpText<"Use NMake/Jom format for the depfile">;
+def fno_canonical_system_headers : Flag<["-"], "fno-canonical-system-headers">,
+ Group<M_Group>, Flags<[CC1Option]>,
+ HelpText<"Do not shorten system header paths in depfiles">;
+def fcanonical_system_headers : Flag<["-"], "fcanonical-system-headers">,
+ Group<M_Group>;
def Mach : Flag<["-"], "Mach">, Group<Link_Group>;
def O0 : Flag<["-"], "O0">, Group<O_Group>, Flags<[CC1Option, HelpHidden]>;
def O4 : Flag<["-"], "O4">, Group<O_Group>, Flags<[CC1Option, HelpHidden]>;
diff --git a/include/clang/Frontend/DependencyOutputOptions.h b/include/clang/Frontend/DependencyOutputOptions.h
index 0be36cd..47016a2 100644
--- a/include/clang/Frontend/DependencyOutputOptions.h
+++ b/include/clang/Frontend/DependencyOutputOptions.h
@@ -30,6 +30,8 @@
unsigned AddMissingHeaderDeps : 1; ///< Add missing headers to dependency list
unsigned PrintShowIncludes : 1; ///< Print cl.exe style /showIncludes info.
unsigned IncludeModuleFiles : 1; ///< Include module file dependencies.
+ unsigned CanonicalSystemHeaders : 1; ///< Try to output a shorter path for
+ /// system header dependencies.
/// The format for the dependency file.
DependencyOutputFormat OutputFormat;
@@ -67,6 +69,7 @@
AddMissingHeaderDeps = 0;
PrintShowIncludes = 0;
IncludeModuleFiles = 0;
+ CanonicalSystemHeaders = 1;
OutputFormat = DependencyOutputFormat::Make;
}
};
diff --git a/lib/Driver/Job.cpp b/lib/Driver/Job.cpp
index 765c057..241c72a 100644
--- a/lib/Driver/Job.cpp
+++ b/lib/Driver/Job.cpp
@@ -73,8 +73,8 @@
// These flags are all of the form -Flag and have no second argument.
ShouldSkip = llvm::StringSwitch<bool>(Flag)
- .Cases("-M", "-MM", "-MG", "-MP", "-MD", true)
- .Case("-MMD", true)
+ .Cases("-M", "-MM", "-MG", "-MP", "-MD", "-MMD", true)
+ .Cases("-fno-canonical-system-headers", "-fcanonical-system-headers", true)
.Default(false);
// Match found.
diff --git a/lib/Driver/ToolChains/Clang.cpp b/lib/Driver/ToolChains/Clang.cpp
index 12713f8..1304042 100644
--- a/lib/Driver/ToolChains/Clang.cpp
+++ b/lib/Driver/ToolChains/Clang.cpp
@@ -964,6 +964,13 @@
Args.AddLastArg(CmdArgs, options::OPT_C);
Args.AddLastArg(CmdArgs, options::OPT_CC);
+ if (Arg *A = Args.getLastArg(options::OPT_fno_canonical_system_headers,
+ options::OPT_fcanonical_system_headers)) {
+ if (A->getOption().matches(options::OPT_fno_canonical_system_headers)) {
+ CmdArgs.push_back("-fno-canonical-system-headers");
+ }
+ }
+
// Handle dependency file generation.
if ((A = Args.getLastArg(options::OPT_M, options::OPT_MM)) ||
(A = Args.getLastArg(options::OPT_MD)) ||
diff --git a/lib/Frontend/CompilerInvocation.cpp b/lib/Frontend/CompilerInvocation.cpp
index 19e26c1..42fd2a1 100644
--- a/lib/Frontend/CompilerInvocation.cpp
+++ b/lib/Frontend/CompilerInvocation.cpp
@@ -1002,6 +1002,7 @@
Opts.Targets = Args.getAllArgValues(OPT_MT);
Opts.IncludeSystemHeaders = Args.hasArg(OPT_sys_header_deps);
Opts.IncludeModuleFiles = Args.hasArg(OPT_module_file_deps);
+ Opts.CanonicalSystemHeaders = !Args.hasArg(OPT_fno_canonical_system_headers);
Opts.UsePhonyTargets = Args.hasArg(OPT_MP);
Opts.ShowHeaderIncludes = Args.hasArg(OPT_H);
Opts.HeaderIncludeOutputFile = Args.getLastArgValue(OPT_header_include_file);
diff --git a/lib/Frontend/DependencyFile.cpp b/lib/Frontend/DependencyFile.cpp
index 561eb9c..b6e4cfa 100644
--- a/lib/Frontend/DependencyFile.cpp
+++ b/lib/Frontend/DependencyFile.cpp
@@ -161,6 +161,7 @@
bool AddMissingHeaderDeps;
bool SeenMissingHeader;
bool IncludeModuleFiles;
+ bool CanonicalSystemHeaders;
DependencyOutputFormat OutputFormat;
private:
@@ -176,6 +177,7 @@
AddMissingHeaderDeps(Opts.AddMissingHeaderDeps),
SeenMissingHeader(false),
IncludeModuleFiles(Opts.IncludeModuleFiles),
+ CanonicalSystemHeaders(Opts.CanonicalSystemHeaders),
OutputFormat(Opts.OutputFormat) {
for (const auto &ExtraDep : Opts.ExtraDeps) {
AddFilename(ExtraDep);
@@ -288,6 +290,15 @@
if (!FileMatchesDepCriteria(Filename.data(), FileType))
return;
+ // Try to shorten system header paths like GCC does (unless
+ // -fno-canonical-system-headers is given).
+ if (CanonicalSystemHeaders && isSystem(FileType)) {
+ StringRef RealPath = FE->tryGetRealPathName();
+ if (!RealPath.empty() && RealPath.size() < Filename.size()) {
+ Filename = RealPath;
+ }
+ }
+
AddFilename(llvm::sys::path::remove_leading_dotslash(Filename));
}
diff --git a/lib/Tooling/ArgumentsAdjusters.cpp b/lib/Tooling/ArgumentsAdjusters.cpp
index ac9fd3c..8fcaa8a 100644
--- a/lib/Tooling/ArgumentsAdjusters.cpp
+++ b/lib/Tooling/ArgumentsAdjusters.cpp
@@ -58,7 +58,9 @@
StringRef Arg = Args[i];
// All dependency-file options begin with -M. These include -MM,
// -MF, -MG, -MP, -MT, -MQ, -MD, and -MMD.
- if (!Arg.startswith("-M"))
+ // The exception is -f[no-]canonical-system-headers.
+ if (!Arg.startswith("-M") && Arg != "-fno-canonical-system-headers" &&
+ Arg != "-fcanonical-system-headers")
AdjustedArgs.push_back(Args[i]);
if ((Arg == "-MF") || (Arg == "-MT") || (Arg == "-MQ") ||
diff --git a/test/Preprocessor/dependencies-realpath.c b/test/Preprocessor/dependencies-realpath.c
new file mode 100644
index 0000000..555b79f
--- /dev/null
+++ b/test/Preprocessor/dependencies-realpath.c
@@ -0,0 +1,33 @@
+// RUN: mkdir -p %t/sub/dir
+// RUN: echo > %t/sub/empty.h
+
+// Test that system header paths are expanded
+//
+// RUN: %clang -fsyntax-only -MD -MF %t.d -MT foo %s -isystem %t/sub/dir/..
+// RUN: FileCheck -check-prefix=TEST1 %s < %t.d
+// TEST1: foo:
+// TEST1: sub{{/|\\}}empty.h
+
+// Test that system header paths are not expanded to a longer form
+//
+// RUN: cd %t && %clang -fsyntax-only -MD -MF %t.d -MT foo %s -isystem sub/dir/..
+// RUN: FileCheck -check-prefix=TEST2 %s < %t.d
+// TEST2: foo:
+// TEST2: sub/dir/..{{/|\\}}empty.h
+
+// Test that user header paths are not expanded
+//
+// RUN: %clang -fsyntax-only -MD -MF %t.d -MT foo %s -I %t/sub/dir/..
+// RUN: FileCheck -check-prefix=TEST3 %s < %t.d
+// TEST3: foo:
+// TEST3: sub/dir/..{{/|\\}}empty.h
+
+// Test that system header paths are not expanded with -fno-canonical-system-headers
+// (and also that the -fsystem-system-headers option is accepted)
+//
+// RUN: %clang -fsyntax-only -MD -MF %t.d -MT foo %s -I %t/sub/dir/.. -fcanonical-system-headers -fno-canonical-system-headers
+// RUN: FileCheck -check-prefix=TEST4 %s < %t.d
+// TEST4: foo:
+// TEST4: sub/dir/..{{/|\\}}empty.h
+
+#include <empty.h>
