Frontend: support -I=path for sysroot expansion
From the GCC manpage:
-I dir
... If dir begins with =, then the = will be replaced by the sysroot prefix;
see --sysroot and -isysroot.
Add support to expand the `=` as a prefix of the include path with the sysroot
if specified. `-isysroot` takes precedence over `--sysroot` as the normal
argument behaviour occurs. The ordering of the `-isysroot` is relevant to the
path substituted. If no `--sysroot=` or `-isysroot` option is present, the = is
not expanded.
Resolves PR26965!
llvm-svn: 268777
diff --git a/clang/test/Preprocessor/sysroot-prefix.c b/clang/test/Preprocessor/sysroot-prefix.c
new file mode 100644
index 0000000..feea502
--- /dev/null
+++ b/clang/test/Preprocessor/sysroot-prefix.c
@@ -0,0 +1,28 @@
+// RUN: %clang_cc1 -v -isysroot /var/empty -I /dev/null -E %s -o /dev/null 2>&1 | FileCheck -check-prefix CHECK-ISYSROOT_NO_SYSROOT %s
+// RUN: %clang_cc1 -v -isysroot /var/empty -I =/dev/null -E %s -o /dev/null 2>&1 | FileCheck -check-prefix CHECK-ISYSROOT_SYSROOT_DEV_NULL %s
+// RUN: %clang_cc1 -v -I =/dev/null -E %s -o /dev/null 2>&1 | FileCheck -check-prefix CHECK-NO_ISYSROOT_SYSROOT_DEV_NULL %s
+// RUN: %clang_cc1 -v -isysroot /var/empty -I =null -E %s -o /dev/null 2>&1 | FileCheck -check-prefix CHECK-ISYSROOT_SYSROOT_NULL %s
+// RUN: %clang_cc1 -v -isysroot /var/empty -isysroot /var/empty/root -I =null -E %s -o /dev/null 2>&1 | FileCheck -check-prefix CHECK-ISYSROOT_ISYSROOT_SYSROOT_NULL %s
+// RUN: %clang_cc1 -v -isysroot /var/empty/root -isysroot /var/empty -I =null -E %s -o /dev/null 2>&1 | FileCheck -check-prefix CHECK-ISYSROOT_ISYSROOT_SWAPPED_SYSROOT_NULL %s
+
+// CHECK-ISYSROOT_NO_SYSROOT: ignoring nonexistent directory "/dev/null"
+// CHECK-ISYSROOT_NO_SYSROOT-NOT: ignoring nonexistent directory "/var/empty/dev/null"
+
+// CHECK-NO_ISYSROOT_SYSROOT_DEV_NULL: ignoring nonexistent directory "=/dev/null"
+// CHECK-NO_ISYSROOT_SYSROOT_DEV_NULL-NOT: ignoring nonexistent directory "/dev/null"
+
+// CHECK-ISYSROOT_SYSROOT_DEV_NULL: ignoring nonexistent directory "/var/empty/dev/null"
+// CHECK-ISYSROOT_SYSROOT_DEV_NULL-NOT: ignoring nonexistent directory "/dev/null"
+
+// CHECK-NO_ISYSROOT_SYSROOT: ignoring nonexistent directory "=/dev/null"
+// CHECK-NO_ISYSROOT_SYSROOT-NOT: ignoring nonexistent directory "/var/empty/dev/null"
+
+// CHECK-ISYSROOT_SYSROOT_NULL: ignoring nonexistent directory "/var/empty/null"
+// CHECK-ISYSROOT_SYSROOT_NULL-NOT: ignoring nonexistent directory "=null"
+
+// CHECK-ISYSROOT_ISYSROOT_SYSROOT_NULL: ignoring nonexistent directory "/var/empty/root/null"
+// CHECK-ISYSROOT_ISYSROOT_SYSROOT_NULL-NOT: ignoring nonexistent directory "=null"
+
+// CHECK-ISYSROOT_ISYSROOT_SWAPPED_SYSROOT_NULL: ignoring nonexistent directory "/var/empty/null"
+// CHECK-ISYSROOT_ISYSROOT_SWAPPED_SYSROOT_NULL-NOT: ignoring nonexistent directory "=null"
+