[X86] Generate .cfi_adjust_cfa_offset correctly when pushing arguments

When push instructions are being used to pass function arguments on
the stack, and either EH or debugging are enabled, we need to generate
.cfi_adjust_cfa_offset directives appropriately. For (synch) EH, it is
enough for the CFA offset to be correct at every call site, while
for debugging we want to be correct after every push.

Darwin does not support this well, so don't use pushes whenever it
would be required.

Differential Revision: http://reviews.llvm.org/D13767

llvm-svn: 251904

1 files changed, 53 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/X86/push-cfi-debug.ll b/llvm/test/CodeGen/X86/push-cfi-debug.ll
new file mode 100644
index 00000000000..61110e566e6
--- /dev/null
+++ b/llvm/test/CodeGen/X86/push-cfi-debug.ll
@@ -0,0 +1,53 @@
+; RUN: llc < %s -mtriple=i686-pc-linux | FileCheck %s
+
+
+; Function Attrs: optsize
+declare void @foo(i32, i32) #0
+declare x86_stdcallcc void @stdfoo(i32, i32) #0
+
+; CHECK-LABEL: test1:
+; CHECK: subl $8, %esp
+; CHECK: .cfi_adjust_cfa_offset 8
+; CHECK: pushl $2
+; CHECK: .cfi_adjust_cfa_offset 4
+; CHECK: pushl $1
+; CHECK: .cfi_adjust_cfa_offset 4
+; CHECK: calll foo
+; CHECK: addl $16, %esp
+; CHECK: .cfi_adjust_cfa_offset -16
+; CHECK: subl $8, %esp
+; CHECK: .cfi_adjust_cfa_offset 8
+; CHECK: pushl $4
+; CHECK: .cfi_adjust_cfa_offset 4
+; CHECK: pushl $3
+; CHECK: .cfi_adjust_cfa_offset 4
+; CHECK: calll stdfoo
+; CHECK: .cfi_adjust_cfa_offset -8
+; CHECK: addl $8, %esp
+; CHECK: .cfi_adjust_cfa_offset -8
+define void @test1() #0 {
+entry:
+  tail call void @foo(i32 1, i32 2) #1, !dbg !10
+  tail call x86_stdcallcc void @stdfoo(i32 3, i32 4) #1, !dbg !11
+  ret void, !dbg !12
+}
+
+attributes #0 = { nounwind optsize }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!7, !8}
+!llvm.ident = !{!9}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 3.8.0 (trunk 250289)", isOptimized: true, runtimeVersion: 0, emissionKind: 1, enums: !2, subprograms: !3)
+!1 = !DIFile(filename: "foo.c", directory: "foo")
+!2 = !{}
+!3 = !{!4}
+!4 = distinct !DISubprogram(name: "test1", scope: !1, file: !1, line: 3, type: !5, isLocal: false, isDefinition: true, scopeLine: 3, isOptimized: true, function: void ()* @test1, variables: !2)
+!5 = !DISubroutineType(types: !6)
+!6 = !{null}
+!7 = !{i32 2, !"Dwarf Version", i32 4}
+!8 = !{i32 2, !"Debug Info Version", i32 3}
+!9 = !{!"clang version 3.8.0 (trunk 250289)"}
+!10 = !DILocation(line: 4, column: 3, scope: !4)
+!11 = !DILocation(line: 5, column: 3, scope: !4)
+!12 = !DILocation(line: 6, column: 1, scope: !4)