12 files changed, 32 insertions, 4 deletions
diff --git a/compiler-rt/lib/asan/asan_rtl_x86_64.S b/compiler-rt/lib/asan/asan_rtl_x86_64.S
index 9c5289856d8a..5ee830d3afc5 100644
--- a/compiler-rt/lib/asan/asan_rtl_x86_64.S
+++ b/compiler-rt/lib/asan/asan_rtl_x86_64.S
@@ -5,6 +5,7 @@
 #include "sanitizer_common/sanitizer_platform.h"
 
 .file "asan_rtl_x86_64.S"
+.att_syntax
 
 #define NAME(n, reg, op, s, i) n##_##op##_##i##_##s##_##reg
 
diff --git a/compiler-rt/lib/builtins/assembly.h b/compiler-rt/lib/builtins/assembly.h
index d1e532813aa2..ac119af521a3 100644
--- a/compiler-rt/lib/builtins/assembly.h
+++ b/compiler-rt/lib/builtins/assembly.h
@@ -337,4 +337,9 @@
 #endif
 #endif
 
+#if defined(__ASSEMBLER__) && (defined(__i386__) || defined(__amd64__)) &&     \
+    !defined(__arm64ec__)
+.att_syntax
+#endif
+
 #endif // COMPILERRT_ASSEMBLY_H
diff --git a/compiler-rt/lib/hwasan/hwasan_setjmp_x86_64.S b/compiler-rt/lib/hwasan/hwasan_setjmp_x86_64.S
index 9804e8d7ceca..a5379d39c6e7 100644
--- a/compiler-rt/lib/hwasan/hwasan_setjmp_x86_64.S
+++ b/compiler-rt/lib/hwasan/hwasan_setjmp_x86_64.S
@@ -30,6 +30,7 @@
 
 .section .text
 .file "hwasan_setjmp_x86_64.S"
+.att_syntax
 
 .global ASM_WRAPPER_NAME(setjmp)
 ASM_TYPE_FUNCTION(ASM_WRAPPER_NAME(setjmp))
diff --git a/compiler-rt/lib/orc/elfnix_tls.x86-64.S b/compiler-rt/lib/orc/elfnix_tls.x86-64.S
index b3e0bef00867..da202127bdbf 100644
--- a/compiler-rt/lib/orc/elfnix_tls.x86-64.S
+++ b/compiler-rt/lib/orc/elfnix_tls.x86-64.S
@@ -13,6 +13,7 @@
 
 // The content of this file is x86_64-only
 #if defined(__x86_64__)
+.att_syntax
 
 #define REGISTER_SAVE_SPACE_SIZE        512
 
diff --git a/compiler-rt/lib/orc/sysv_reenter.x86-64.S b/compiler-rt/lib/orc/sysv_reenter.x86-64.S
index 0a36280f1d1f..99615c0468b9 100644
--- a/compiler-rt/lib/orc/sysv_reenter.x86-64.S
+++ b/compiler-rt/lib/orc/sysv_reenter.x86-64.S
@@ -12,6 +12,7 @@
 
 // The content of this file is x86_64-only
 #if defined(__x86_64__)
+.att_syntax
 
 // Save all GRPS except %rsp.
 // This value is also subtracted from %rsp below, despite the fact that %rbp
diff --git a/compiler-rt/lib/profile/CMakeLists.txt b/compiler-rt/lib/profile/CMakeLists.txt
index ac1451c8ceed..a6402f80b890 100644
--- a/compiler-rt/lib/profile/CMakeLists.txt
+++ b/compiler-rt/lib/profile/CMakeLists.txt
@@ -162,8 +162,7 @@ if(APPLE)
     CFLAGS ${EXTRA_FLAGS}
     SOURCES ${PROFILE_SOURCES}
     ADDITIONAL_HEADERS ${PROFILE_HEADERS}
-    PARENT_TARGET profile
-    EXTENSIONS ON)
+    PARENT_TARGET profile)
 else()
   add_compiler_rt_runtime(clang_rt.profile
     STATIC
@@ -171,6 +170,5 @@ else()
     CFLAGS ${EXTRA_FLAGS}
     SOURCES ${PROFILE_SOURCES}
     ADDITIONAL_HEADERS ${PROFILE_HEADERS}
-    PARENT_TARGET profile
-    EXTENSIONS ON)
+    PARENT_TARGET profile)
 endif()
diff --git a/compiler-rt/lib/profile/GCDAProfiling.c b/compiler-rt/lib/profile/GCDAProfiling.c
index ac01805e70ad..523ade5eafc1 100644
--- a/compiler-rt/lib/profile/GCDAProfiling.c
+++ b/compiler-rt/lib/profile/GCDAProfiling.c
@@ -21,6 +21,11 @@
 
 #if !defined(__Fuchsia__)
 
+#if defined(__linux__)
+// For fdopen()
+#define _DEFAULT_SOURCE
+#endif
+
 #include <errno.h>
 #include <fcntl.h>
 #include <stdint.h>
diff --git a/compiler-rt/lib/profile/InstrProfilingFile.c b/compiler-rt/lib/profile/InstrProfilingFile.c
index 354f21b78615..71127b05aafb 100644
--- a/compiler-rt/lib/profile/InstrProfilingFile.c
+++ b/compiler-rt/lib/profile/InstrProfilingFile.c
@@ -8,6 +8,11 @@
 
 #if !defined(__Fuchsia__)
 
+#if defined(__linux__)
+// For fileno(), ftruncate(), getpagesize(), setenv()
+#define _DEFAULT_SOURCE
+#endif
+
 #include <assert.h>
 #include <errno.h>
 #include <stdio.h>
diff --git a/compiler-rt/lib/profile/InstrProfilingUtil.c b/compiler-rt/lib/profile/InstrProfilingUtil.c
index 0fae91cfb895..a9d9df813764 100644
--- a/compiler-rt/lib/profile/InstrProfilingUtil.c
+++ b/compiler-rt/lib/profile/InstrProfilingUtil.c
@@ -12,6 +12,11 @@
 #include <windows.h>
 #include "WindowsMMap.h"
 #else
+#if defined(__linux__)
+// For fdopen(), fileno(), getpagesize(), madvise()
+#define _DEFAULT_SOURCE
+#endif
+
 #include <errno.h>
 #include <fcntl.h>
 #include <sys/file.h>
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors_vfork_i386.inc.S b/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors_vfork_i386.inc.S
index c633014e2daa..5ef090c003dc 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors_vfork_i386.inc.S
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors_vfork_i386.inc.S
@@ -2,6 +2,8 @@
 
 #include "sanitizer_common/sanitizer_asm.h"
 
+.att_syntax
+
 .comm _ZN14__interception10real_vforkE,4,4
 .globl ASM_WRAPPER_NAME(vfork)
 ASM_TYPE_FUNCTION(ASM_WRAPPER_NAME(vfork))
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors_vfork_x86_64.inc.S b/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors_vfork_x86_64.inc.S
index 5500f817aec5..9c85407fe022 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors_vfork_x86_64.inc.S
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors_vfork_x86_64.inc.S
@@ -2,6 +2,8 @@
 
 #include "sanitizer_common/sanitizer_asm.h"
 
+.att_syntax
+
 .comm _ZN14__interception10real_vforkE,8,8
 .globl ASM_WRAPPER_NAME(vfork)
 ASM_TYPE_FUNCTION(ASM_WRAPPER_NAME(vfork))
diff --git a/compiler-rt/lib/tsan/rtl/tsan_rtl_amd64.S b/compiler-rt/lib/tsan/rtl/tsan_rtl_amd64.S
index f848be9dd46c..8b9b706a822d 100644
--- a/compiler-rt/lib/tsan/rtl/tsan_rtl_amd64.S
+++ b/compiler-rt/lib/tsan/rtl/tsan_rtl_amd64.S
@@ -3,6 +3,8 @@
 
 #include "sanitizer_common/sanitizer_asm.h"
 
+.att_syntax
+
 #if !defined(__APPLE__)
 .section .text
 #else