libphobos: libdruntime doesn't support shadow stack (PR95680)

The first implementation hit a front-end implementation bug where
version conditions are resolved ahead of static if confitions.

The logic for whether to use asm implemented fiber_switchContext or
libc's swapcontext has been moved from GNU_Enable_CET to version CET.

libphobos/ChangeLog:

	PR d/95680
	PR d/97007
	* Makefile.am (AM_MAKEFLAGS): Remove $(CET_FLAGS).
	* Makefile.in: Regenerate.
	* configure: Regenerate.
	* configure.ac (DCFG_ENABLE_CET): Remove substitution.
	(CET_DFLAGS): Substitute.
	* libdruntime/Makefile.am (AM_DFLAGS): Add $(CET_DFLAGS).
	(AM_CFLAGS): Add $(CET_FLAGS).
	(AM_CCASFLAGS): Likewise.
	* libdruntime/Makefile.in: Regenerate.
	* libdruntime/core/thread.d: Replace static if GNU_Enable_CET
	condition with `version (CET)'.
	* libdruntime/gcc/config.d.in (GNU_Enable_CET): Remove.
	* src/Makefile.am (AM_DFLAGS): Add $(CET_DFLAGS).
	(AM_CFLAGS): Add $(CET_FLAGS).
	* src/Makefile.in: Regenerate.
	* testsuite/Makefile.in: Regenerate.
	* testsuite/testsuite_flags.in: Add $(CET_DFLAGS) to --gdcflags.

4 files changed, 32 insertions, 28 deletions

diff --git a/libphobos/libdruntime/Makefile.am b/libphobos/libdruntime/Makefile.am
index 1d340a0..4136642 100644
--- a/libphobos/libdruntime/Makefile.am
+++ b/libphobos/libdruntime/Makefile.am
@@ -24,7 +24,11 @@ D_EXTRA_DFLAGS=-nostdinc -I $(srcdir) -I .
 # D flags for compilation
 AM_DFLAGS= \
 	$(phobos_compiler_pic_flag) \
-	$(WARN_DFLAGS) $(CHECKING_DFLAGS)
+	$(WARN_DFLAGS) $(CHECKING_DFLAGS) $(CET_DFLAGS)
+
+# Flags for other kinds of sources
+AM_CFLAGS=$(CET_FLAGS)
+AM_CCASFLAGS=$(CET_FLAGS)
 
 # Install all D and DI files
 ALL_DRUNTIME_INSTALL_DSOURCES = $(DRUNTIME_DSOURCES) \
diff --git a/libphobos/libdruntime/Makefile.in b/libphobos/libdruntime/Makefile.in
index 28b4333..d0bb324 100644
--- a/libphobos/libdruntime/Makefile.in
+++ b/libphobos/libdruntime/Makefile.in
@@ -567,6 +567,7 @@ CC = @CC@
 CCAS = @CCAS@
 CCASFLAGS = @CCASFLAGS@
 CC_FOR_BUILD = @CC_FOR_BUILD@
+CET_DFLAGS = @CET_DFLAGS@
 CET_FLAGS = @CET_FLAGS@
 CFLAGS = @CFLAGS@
 CFLAGS_FOR_BUILD = @CFLAGS_FOR_BUILD@
@@ -576,7 +577,6 @@ CPPFLAGS = @CPPFLAGS@
 CYGPATH_W = @CYGPATH_W@
 DCFG_ARM_EABI_UNWINDER = @DCFG_ARM_EABI_UNWINDER@
 DCFG_DLPI_TLS_MODID = @DCFG_DLPI_TLS_MODID@
-DCFG_ENABLE_CET = @DCFG_ENABLE_CET@
 DCFG_HAVE_64BIT_ATOMICS = @DCFG_HAVE_64BIT_ATOMICS@
 DCFG_HAVE_ATOMIC_BUILTINS = @DCFG_HAVE_ATOMIC_BUILTINS@
 DCFG_HAVE_LIBATOMIC = @DCFG_HAVE_LIBATOMIC@
@@ -719,9 +719,13 @@ D_EXTRA_DFLAGS = -nostdinc -I $(srcdir) -I .
 # D flags for compilation
 AM_DFLAGS = \
 	$(phobos_compiler_pic_flag) \
-	$(WARN_DFLAGS) $(CHECKING_DFLAGS)
+	$(WARN_DFLAGS) $(CHECKING_DFLAGS) $(CET_DFLAGS)
 
 
+# Flags for other kinds of sources
+AM_CFLAGS = $(CET_FLAGS)
+AM_CCASFLAGS = $(CET_FLAGS)
+
 # Install all D and DI files
 ALL_DRUNTIME_INSTALL_DSOURCES = $(DRUNTIME_DSOURCES) \
 	$(DRUNTIME_DSOURCES_BIONIC) $(DRUNTIME_DSOURCES_DARWIN) \
diff --git a/libphobos/libdruntime/core/thread.d b/libphobos/libdruntime/core/thread.d
index 8f4603d..eaf088d 100644
--- a/libphobos/libdruntime/core/thread.d
+++ b/libphobos/libdruntime/core/thread.d
@@ -3586,45 +3586,44 @@ private
     }
     else version (X86)
     {
-        import gcc.config;
-
         version = AlignFiberStackTo16Byte;
 
-        static if (!GNU_Enable_CET)
+        version (CET)
+        {
+            // fiber_switchContext does not support shadow stack from
+            // Intel CET.  So use ucontext implementation.
+        }
+        else
         {
             version = AsmExternal;
 
             version (MinGW)
-            {
                 version = GNU_AsmX86_Windows;
-            }
             else version (Posix)
-            {
                 version = AsmX86_Posix;
-            }
         }
     }
     else version (X86_64)
     {
-        import gcc.config;
-
         version = AlignFiberStackTo16Byte;
 
-        static if (!GNU_Enable_CET)
+        version (CET)
         {
-            version (D_X32)
-            {
-                // let X32 be handled by ucontext swapcontext
-            }
-            else
-            {
-                version = AsmExternal;
+            // fiber_switchContext does not support shadow stack from
+            // Intel CET.  So use ucontext implementation.
+        }
+        else version (D_X32)
+        {
+            // let X32 be handled by ucontext swapcontext
+        }
+        else
+        {
+            version = AsmExternal;
 
-                version (MinGW)
-                    version = GNU_AsmX86_64_Windows;
-                else version (Posix)
-                    version = AsmX86_64_Posix;
-            }
+            version (MinGW)
+                version = GNU_AsmX86_64_Windows;
+            else version (Posix)
+                version = AsmX86_64_Posix;
         }
     }
     else version (PPC)
diff --git a/libphobos/libdruntime/gcc/config.d.in b/libphobos/libdruntime/gcc/config.d.in
index 9ac7d05..6301aaf 100644
--- a/libphobos/libdruntime/gcc/config.d.in
+++ b/libphobos/libdruntime/gcc/config.d.in
@@ -49,6 +49,3 @@ enum GNU_Have_LibAtomic = @DCFG_HAVE_LIBATOMIC@;
 
 // Do we have qsort_r function
 enum Have_Qsort_R = @DCFG_HAVE_QSORT_R@;
-
-// Whether libphobos been configured with --enable-cet.
-enum GNU_Enable_CET = @DCFG_ENABLE_CET@;