Add a no dwarf version of assembler macros.
For the __release and __release_rt functions, the previous macros
would add a dwarf cfi entry for the function with no values. This works
with libunwind since it always tries the arm unwind information first.
This change removes those entries by creating a no dwarf version of the
assembler macro.
Change-Id: Ib93e42fff5a79b8d770eab0071fdee7d2afa988d
diff --git a/libc/arch-arm/bionic/__restore.S b/libc/arch-arm/bionic/__restore.S
index 9898125..8c1e41d 100644
--- a/libc/arch-arm/bionic/__restore.S
+++ b/libc/arch-arm/bionic/__restore.S
@@ -34,7 +34,9 @@
// __restore_rt (but covered by the .fnstart/.fnend) so that although they're
// not inside the functions from objdump's point of view, an unwinder that
// blindly looks at the previous instruction (but is then smart enough to check
-// the DWARF information to find out where it landed) gets the right answer.
+// the unwind information to find out where it landed) gets the right answer.
+// Make sure not to have both DWARF and ARM unwind information, so only
+// use the ARM unwind information.
// We need to place .fnstart ourselves (but we may as well keep the free .fnend).
#undef __bionic_asm_custom_entry
@@ -44,18 +46,18 @@
.save {r0-r15}
.pad #32
nop
-ENTRY_PRIVATE(__restore)
+ENTRY_PRIVATE_NO_DWARF(__restore)
// This function must have exactly this instruction sequence.
mov r7, #__NR_sigreturn
swi #0
-END(__restore)
+END_NO_DWARF(__restore)
.fnstart
.save {r0-r15}
.pad #160
nop
-ENTRY_PRIVATE(__restore_rt)
+ENTRY_PRIVATE_NO_DWARF(__restore_rt)
// This function must have exactly this instruction sequence.
mov r7, #__NR_rt_sigreturn
swi #0
-END(__restore_rt)
+END_NO_DWARF(__restore_rt)
diff --git a/libc/private/bionic_asm.h b/libc/private/bionic_asm.h
index 5fca222..e2084d4 100644
--- a/libc/private/bionic_asm.h
+++ b/libc/private/bionic_asm.h
@@ -38,25 +38,36 @@
#include <machine/asm.h>
-#define ENTRY(f) \
+#define ENTRY_NO_DWARF(f) \
.text; \
.globl f; \
.align __bionic_asm_align; \
.type f, __bionic_asm_function_type; \
f: \
__bionic_asm_custom_entry(f); \
+
+#define ENTRY(f) \
+ ENTRY_NO_DWARF(f) \
.cfi_startproc \
+#define END_NO_DWARF(f) \
+ .size f, .-f; \
+ __bionic_asm_custom_end(f) \
+
#define END(f) \
.cfi_endproc; \
- .size f, .-f; \
- __bionic_asm_custom_end(f) \
+ END_NO_DWARF(f) \
/* Like ENTRY, but with hidden visibility. */
#define ENTRY_PRIVATE(f) \
ENTRY(f); \
.hidden f \
+/* Like ENTRY_NO_DWARF, but with hidden visibility. */
+#define ENTRY_PRIVATE_NO_DWARF(f) \
+ ENTRY_NO_DWARF(f); \
+ .hidden f \
+
#define ALIAS_SYMBOL(alias, original) \
.globl alias; \
.equ alias, original