ART: Fix arm32 assembly for Clang

Clang ignores .thumb_func and requires an explicit
.thumb directive, as given by the ARM Unified Assembler
Language. Conditionally add .thumb to thumb2 functions.

Bug: 22762844
Change-Id: I08abdb5f4e0ba5135d4ed850ca3e284203f95a03

diff --git a/runtime/arch/arm/asm_support_arm.S b/runtime/arch/arm/asm_support_arm.S
index 665d2a3..44c7649 100644 (file)
--- a/runtime/arch/arm/asm_support_arm.S
+++ b/runtime/arch/arm/asm_support_arm.S
@@ -50,6 +50,11 @@
 // generated at END.
 .macro DEF_ENTRY thumb_or_arm, name
     \thumb_or_arm
+// Clang ignores .thumb_func and requires an explicit .thumb. Investigate whether we should still
+// carry around the .thumb_func.
+    .ifc \thumb_or_arm, .thumb_func
+        .thumb
+    .endif
     .type \name, #function
     .hidden \name  // Hide this as a global symbol, so we do not incur plt calls.
     .global \name