Add a new attribute called 'jumptable' that creates jump-instruction tables for functions marked with this attribute.
It includes a pass that rewrites all indirect calls to jumptable functions to pass through these tables.
This also adds backend support for generating the jump-instruction tables on ARM and X86.
Note that since the jumptable attribute creates a second function pointer for a
function, any function marked with jumptable must also be marked with unnamed_addr.
llvm-svn: 210280
diff --git a/llvm/test/CodeGen/X86/jump_table_bitcast.ll b/llvm/test/CodeGen/X86/jump_table_bitcast.ll
new file mode 100644
index 0000000..33a798f
--- /dev/null
+++ b/llvm/test/CodeGen/X86/jump_table_bitcast.ll
@@ -0,0 +1,46 @@
+; RUN: llc <%s -jump-table-type=single | FileCheck %s
+target triple = "x86_64-unknown-linux-gnu"
+define i32 @f() unnamed_addr jumptable {
+ ret i32 0
+}
+
+define i32 @g(i8* %a) unnamed_addr jumptable {
+ ret i32 0
+}
+
+define void @h(void ()* %func) unnamed_addr jumptable {
+ ret void
+}
+
+define i32 @main() {
+ %g = alloca i32 (...)*, align 8
+ store i32 (...)* bitcast (i32 ()* @f to i32 (...)*), i32 (...)** %g, align 8
+; CHECK: movq $__llvm_jump_instr_table_0_[[ENTRY:1|2|3]], (%rsp)
+; CHECK: movl $__llvm_jump_instr_table_0_[[ENTRY]], %ecx
+ %1 = load i32 (...)** %g, align 8
+ %call = call i32 (...)* %1()
+ call void (void ()*)* @h(void ()* bitcast (void (void ()*)* @h to void ()*))
+; CHECK: movl $__llvm_jump_instr_table_0_{{1|2|3}}, %edi
+; CHECK: callq h
+
+ %a = call i32 (i32*)* bitcast (i32 (i8*)* @g to i32(i32*)*)(i32* null)
+; CHECK: callq g
+ ret i32 %a
+}
+
+; CHECK: .globl __llvm_jump_instr_table_0_1
+; CHECK: .align 8, 0x90
+; CHECK: .type __llvm_jump_instr_table_0_1,@function
+; CHECK: __llvm_jump_instr_table_0_1:
+; CHECK: jmp {{f|g|h}}@PLT
+; CHECK: .globl __llvm_jump_instr_table_0_2
+; CHECK: .align 8, 0x90
+; CHECK: .type __llvm_jump_instr_table_0_2,@function
+; CHECK: __llvm_jump_instr_table_0_2:
+; CHECK: jmp {{f|g|h}}@PLT
+; CHECK: .globl __llvm_jump_instr_table_0_3
+; CHECK: .align 8, 0x90
+; CHECK: .type __llvm_jump_instr_table_0_3,@function
+; CHECK: __llvm_jump_instr_table_0_3:
+; CHECK: jmp {{f|g|h}}@PLT
+