logan created this revision.
logan added reviewers: mclow.lists, rengolin.
logan added a subscriber: cfe-commits.
Herald added subscribers: samparker, rengolin, aemerson.

GCC 4.7 or newer emits 0x90 (indirect | pcrel) as the ttype encoding.
This would hit an assertion in cxa_personality.cpp.  This commit fixes
the problem by relaxing the assertion.

http://llvm.org/PR28884

https://reviews.llvm.org/D24085

Files:
  src/cxa_personality.cpp
  test/lit.cfg
  test/lit.site.cfg.in
  test/native/arm-linux-eabi/lit.local.cfg
  test/native/arm-linux-eabi/ttype-encoding-00.pass.sh.s
  test/native/arm-linux-eabi/ttype-encoding-90.pass.sh.s

Index: test/native/arm-linux-eabi/ttype-encoding-90.pass.sh.s
===================================================================
--- /dev/null
+++ test/native/arm-linux-eabi/ttype-encoding-90.pass.sh.s
@@ -0,0 +1,96 @@
+@ RUN: %cxx %flags %link_flags %s -o %t.exe
+@ RUN: %exec %t.exe
+
+@ PURPOSE: Check that 0x90 is a valid value for ttype encoding.
+
+@ NOTE:
+@
+@ This file is generated from the following C++ source code and then change the
+@ `TType Encoding` to 0x90.
+@
+@ ```
+@ int main() {
+@   try {
+@     throw 5;
+@   } catch (int i) {
+@     if (i != 5)
+@       abort();
+@     return 0;
+@   }
+@ }
+@ ```
+
+	.syntax unified
+
+	.text
+	.globl	main
+	.p2align	2
+	.type	main,%function
+main:                                   @ @main
+.Lfunc_begin0:
+	.fnstart
+@ BB#0:                                 @ %entry
+	.save	{r11, lr}
+	push	{r11, lr}
+	.setfp	r11, sp
+	mov	r11, sp
+	mov	r0, #4
+	bl	__cxa_allocate_exception
+	mov	r1, #5
+	str	r1, [r0]
+.Ltmp0:
+	ldr	r1, .LCPI0_0
+	mov	r2, #0
+	bl	__cxa_throw
+.Ltmp1:
+
+@ BB#2:                                 @ %lpad
+.Ltmp2:
+	bl	__cxa_begin_catch
+	ldr	r0, [r0]
+	cmp	r0, #5
+	bne	.LBB0_4
+@ BB#3:                                 @ %if.end
+	bl	__cxa_end_catch
+	mov	r0, #0
+	pop	{r11, lr}
+	bx	lr
+.LBB0_4:                                @ %if.then
+	bl	abort
+	.p2align	2
+@ BB#5:
+.LCPI0_0:
+	.long	_ZTIi
+.Lfunc_end0:
+
+	.size	main, .Lfunc_end0-main
+	.globl	__gxx_personality_v0
+	.personality __gxx_personality_v0
+	.handlerdata
+	.p2align	2
+GCC_except_table0:
+.Lexception0:
+	.byte	255                     @ @LPStart Encoding = omit
+	.byte	0x90                    @ @TType Encoding = indirect | pcrel
+	.asciz	"\257\200"              @ @TType base offset
+	.byte	3                       @ Call site Encoding = udata4
+	.byte	39                      @ Call site table length
+	.long	.Lfunc_begin0-.Lfunc_begin0 @ >> Call Site 1 <<
+	.long	.Ltmp0-.Lfunc_begin0    @   Call between .Lfunc_begin0 and .Ltmp0
+	.long	0                       @     has no landing pad
+	.byte	0                       @   On action: cleanup
+	.long	.Ltmp0-.Lfunc_begin0    @ >> Call Site 2 <<
+	.long	.Ltmp1-.Ltmp0           @   Call between .Ltmp0 and .Ltmp1
+	.long	.Ltmp2-.Lfunc_begin0    @     jumps to .Ltmp2
+	.byte	1                       @   On action: 1
+	.long	.Ltmp1-.Lfunc_begin0    @ >> Call Site 3 <<
+	.long	.Lfunc_end0-.Ltmp1      @   Call between .Ltmp1 and .Lfunc_end0
+	.long	0                       @     has no landing pad
+	.byte	0                       @   On action: cleanup
+	.byte	1                       @ >> Action Record 1 <<
+                                        @   Catch TypeInfo 1
+	.byte	0                       @   No further actions
+                                        @ >> Catch TypeInfos <<
+	.long	_ZTIi(target2)          @ TypeInfo 1
+	.p2align	2
+	.fnend
Index: test/native/arm-linux-eabi/ttype-encoding-00.pass.sh.s
===================================================================
--- /dev/null
+++ test/native/arm-linux-eabi/ttype-encoding-00.pass.sh.s
@@ -0,0 +1,97 @@
+@ RUN: %cxx %flags %link_flags %s -o %t.exe
+@ RUN: %exec %t.exe
+
+@ PURPOSE: Check that 0x00 is a valid value for ttype encoding.  LLVM and
+@ GCC 4.6 are generating 0x00 as ttype encoding.  libc++abi should provide
+@ legacy support.
+
+@ NOTE:
+@
+@ This file is generated from the following C++ source code:
+@
+@ ```
+@ int main() {
+@   try {
+@     throw 5;
+@   } catch (int i) {
+@     if (i != 5)
+@       abort();
+@     return 0;
+@   }
+@ }
+@ ```
+
+	.syntax unified
+
+	.text
+	.globl	main
+	.p2align	2
+	.type	main,%function
+main:                                   @ @main
+.Lfunc_begin0:
+	.fnstart
+@ BB#0:                                 @ %entry
+	.save	{r11, lr}
+	push	{r11, lr}
+	.setfp	r11, sp
+	mov	r11, sp
+	mov	r0, #4
+	bl	__cxa_allocate_exception
+	mov	r1, #5
+	str	r1, [r0]
+.Ltmp0:
+	ldr	r1, .LCPI0_0
+	mov	r2, #0
+	bl	__cxa_throw
+.Ltmp1:
+
+@ BB#2:                                 @ %lpad
+.Ltmp2:
+	bl	__cxa_begin_catch
+	ldr	r0, [r0]
+	cmp	r0, #5
+	bne	.LBB0_4
+@ BB#3:                                 @ %if.end
+	bl	__cxa_end_catch
+	mov	r0, #0
+	pop	{r11, lr}
+	bx	lr
+.LBB0_4:                                @ %if.then
+	bl	abort
+	.p2align	2
+@ BB#5:
+.LCPI0_0:
+	.long	_ZTIi
+.Lfunc_end0:
+
+	.size	main, .Lfunc_end0-main
+	.globl	__gxx_personality_v0
+	.personality __gxx_personality_v0
+	.handlerdata
+	.p2align	2
+GCC_except_table0:
+.Lexception0:
+	.byte	255                     @ @LPStart Encoding = omit
+	.byte	0                       @ @TType Encoding = absptr
+	.asciz	"\257\200"              @ @TType base offset
+	.byte	3                       @ Call site Encoding = udata4
+	.byte	39                      @ Call site table length
+	.long	.Lfunc_begin0-.Lfunc_begin0 @ >> Call Site 1 <<
+	.long	.Ltmp0-.Lfunc_begin0    @   Call between .Lfunc_begin0 and .Ltmp0
+	.long	0                       @     has no landing pad
+	.byte	0                       @   On action: cleanup
+	.long	.Ltmp0-.Lfunc_begin0    @ >> Call Site 2 <<
+	.long	.Ltmp1-.Ltmp0           @   Call between .Ltmp0 and .Ltmp1
+	.long	.Ltmp2-.Lfunc_begin0    @     jumps to .Ltmp2
+	.byte	1                       @   On action: 1
+	.long	.Ltmp1-.Lfunc_begin0    @ >> Call Site 3 <<
+	.long	.Lfunc_end0-.Ltmp1      @   Call between .Ltmp1 and .Lfunc_end0
+	.long	0                       @     has no landing pad
+	.byte	0                       @   On action: cleanup
+	.byte	1                       @ >> Action Record 1 <<
+                                        @   Catch TypeInfo 1
+	.byte	0                       @   No further actions
+                                        @ >> Catch TypeInfos <<
+	.long	_ZTIi(target2)          @ TypeInfo 1
+	.p2align	2
+	.fnend
Index: test/native/arm-linux-eabi/lit.local.cfg
===================================================================
--- /dev/null
+++ test/native/arm-linux-eabi/lit.local.cfg
@@ -0,0 +1,6 @@
+def is_arm_linux_eabi(triple):
+    return ('arm' in triple) and ('linux' in triple) and ('eabi' in triple)
+
+is_native = config.root.host_triple == config.root.target_triple
+if not is_native or not is_arm_linux_eabi(config.root.host_triple):
+    config.unsupported = True
Index: test/lit.site.cfg.in
===================================================================
--- test/lit.site.cfg.in
+++ test/lit.site.cfg.in
@@ -17,6 +17,8 @@
 config.libcxxabi_shared         = "@LIBCXXABI_ENABLE_SHARED@"
 config.enable_shared            = "@LIBCXX_ENABLE_SHARED@"
 config.enable_exceptions        = "@LIBCXXABI_ENABLE_EXCEPTIONS@"
+config.host_triple              = "@LLVM_HOST_TRIPLE@"
+config.target_triple            = "@TARGET_TRIPLE@"
 
 # Let the main config do the real work.
 lit_config.load_config(config, "@LIBCXXABI_SOURCE_DIR@/test/lit.cfg")
Index: test/lit.cfg
===================================================================
--- test/lit.cfg
+++ test/lit.cfg
@@ -18,7 +18,7 @@
 config.name = 'libc++abi'
 
 # suffixes: A list of file extensions to treat as test files.
-config.suffixes = ['.cpp']
+config.suffixes = ['.cpp', '.s']
 
 # test_source_root: The root path where tests are located.
 config.test_source_root = os.path.dirname(__file__)
Index: src/cxa_personality.cpp
===================================================================
--- src/cxa_personality.cpp
+++ src/cxa_personality.cpp
@@ -348,7 +348,18 @@
         call_terminate(native_exception, unwind_exception);
     }
 
-    assert(ttypeEncoding == DW_EH_PE_absptr && "Unexpected TTypeEncoding");
+    // Assume each type_info takes sizeof(uintptr_t) bytes.  This assumption
+    // should be valid in ARM EHABI implementations.  ARM EHABI 9.2 demands
+    // type_infos are relocated by R_ARM_TARGET2, and 4.4.2 specifies that
+    // R_ARM_TARGET2 is a 32-bit relocation.
+    //
+    // NOTE: GCC 4.7 (or newer) emits 0x90 (DW_EH_PE_pcrel | DW_EH_PE_indirect)
+    // for arm-linux-gnueabi* and 0x10 (DW_EH_PE_pcrel) for baremetal.  OTOH,
+    // LLVM and GCC 4.6 (or older) emit 0x00 (DW_EH_PE_absptr).  Thus, we have
+    // to mask ttypeEncoding with 0x0f.
+    assert(((ttypeEncoding & 0x0f) == DW_EH_PE_absptr ||
+            (ttypeEncoding & 0x0f) == DW_EH_PE_udata4) &&
+           "Unexpected TTypeEncoding");
     (void)ttypeEncoding;
 
     const uint8_t* ttypePtr = classInfo - ttypeIndex * sizeof(uintptr_t);
@@ -415,7 +426,18 @@
         call_terminate(false, unwind_exception);
     }
 
-    assert(ttypeEncoding == DW_EH_PE_absptr && "Unexpected TTypeEncoding");
+    // Assume each type_info takes sizeof(uintptr_t) bytes.  This assumption
+    // should be valid in ARM EHABI implementations.  ARM EHABI 9.2 demands
+    // type_infos are relocated by R_ARM_TARGET2, and 4.4.2 specifies that
+    // R_ARM_TARGET2 is a 32-bit relocation.
+    //
+    // NOTE: GCC 4.7 (or newer) emits 0x90 (DW_EH_PE_pcrel | DW_EH_PE_indirect)
+    // for arm-linux-gnueabi* and 0x10 (DW_EH_PE_pcrel) for baremetal.  OTOH,
+    // LLVM and GCC 4.6 (or older) emit 0x00 (DW_EH_PE_absptr).  Thus, we have
+    // to mask ttypeEncoding with 0x0f.
+    assert(((ttypeEncoding & 0x0f) == DW_EH_PE_absptr ||
+            (ttypeEncoding & 0x0f) == DW_EH_PE_udata4) &&
+           "Unexpected TTypeEncoding");
     (void)ttypeEncoding;
 
     // specIndex is negative of 1-based byte offset into classInfo;
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