Update this a bit more to represent how the prologue should work:

a) frame setup instructions define the prologue
b) we shouldn't change our location mid-stream

Add a test to make sure that the stack adjustment stays within
the prologue.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165250 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 39 insertions, 5 deletions

diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index f79854dc44..fd2fd24331 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -1355,9 +1355,10 @@ void DwarfDebug::beginFunction(const MachineFunction *MF) {
         if (!MI->isLabel())
           AtBlockEntry = false;
 
-        // First known non DBG_VALUE location marks beginning of function
-        // body.
-        if (PrologEndLoc.isUnknown() && !MI->getDebugLoc().isUnknown())
+        // First known non-DBG_VALUE and non-frame setup location marks
+        // the beginning of the function body.
+        if (!MI->getFlag(MachineInstr::FrameSetup) &&
+            (PrologEndLoc.isUnknown() && !MI->getDebugLoc().isUnknown()))
           PrologEndLoc = MI->getDebugLoc();
 
         // Check if the instruction clobbers any registers with debug vars.
diff --git a/lib/Target/X86/X86FrameLowering.cpp b/lib/Target/X86/X86FrameLowering.cpp
index ce53c5a4ef..944dbc9519 100644
--- a/lib/Target/X86/X86FrameLowering.cpp
+++ b/lib/Target/X86/X86FrameLowering.cpp
@@ -836,8 +836,6 @@ void X86FrameLowering::emitPrologue(MachineFunction &MF) const {
     MI->getOperand(3).setIsDead();
   }
 
-  DL = MBB.findDebugLoc(MBBI);
-
   // If there is an SUB32ri of ESP immediately before this instruction, merge
   // the two. This can be the case when tail call elimination is enabled and
   // the callee has more arguments then the caller.
diff --git a/test/DebugInfo/X86/prologue-stack.ll b/test/DebugInfo/X86/prologue-stack.ll
new file mode 100644
index 0000000000..929db51902
--- /dev/null
+++ b/test/DebugInfo/X86/prologue-stack.ll
@@ -0,0 +1,35 @@
+; RUN: llc -disable-fp-elim -O0 %s -mtriple x86_64-unknown-linux-gnu -o - | FileCheck %s
+
+; int callme(int);
+; int isel_line_test2() {
+;   callme(400);
+;   return 0;
+; }
+
+define i32 @isel_line_test2() nounwind uwtable {
+  ; The stack adjustment should be part of the prologue.
+  ; CHECK: isel_line_test2:
+  ; CHECK: {{subq|leaq}} {{.*}}, %rsp
+  ; CHECK: .loc 1 5 3 prologue_end
+entry:
+  %call = call i32 @callme(i32 400), !dbg !10
+  ret i32 0, !dbg !12
+}
+
+declare i32 @callme(i32)
+
+!llvm.dbg.cu = !{!0}
+
+!0 = metadata !{i32 786449, i32 0, i32 12, metadata !"bar.c", metadata !"/usr/local/google/home/echristo/tmp", metadata !"clang version 3.2 (trunk 164980) (llvm/trunk 164979)", i1 true, i1 false, metadata !"", i32 0, metadata !1, metadata !1, metadata !3, metadata !1} ; [ DW_TAG_compile_unit ] [/usr/local/google/home/echristo/tmp/bar.c] [DW_LANG_C99]
+!1 = metadata !{metadata !2}
+!2 = metadata !{i32 0}
+!3 = metadata !{metadata !4}
+!4 = metadata !{metadata !5}
+!5 = metadata !{i32 786478, i32 0, metadata !6, metadata !"isel_line_test2", metadata !"isel_line_test2", metadata !"", metadata !6, i32 3, metadata !7, i1 false, i1 true, i32 0, i32 0, null, i32 0, i1 false, i32 ()* @isel_line_test2, null, null, metadata !1, i32 4} ; [ DW_TAG_subprogram ] [line 3] [def] [scope 4] [isel_line_test2]
+!6 = metadata !{i32 786473, metadata !"bar.c", metadata !"/usr/local/google/home/echristo/tmp", null} ; [ DW_TAG_file_type ]
+!7 = metadata !{i32 786453, i32 0, metadata !"", i32 0, i32 0, i64 0, i64 0, i64 0, i32 0, null, metadata !8, i32 0, i32 0} ; [ DW_TAG_subroutine_type ] [line 0, size 0, align 0, offset 0] [from ]
+!8 = metadata !{metadata !9}
+!9 = metadata !{i32 786468, null, metadata !"int", null, i32 0, i64 32, i64 32, i64 0, i32 0, i32 5} ; [ DW_TAG_base_type ] [int] [line 0, size 32, align 32, offset 0, enc DW_ATE_signed]
+!10 = metadata !{i32 5, i32 3, metadata !11, null}
+!11 = metadata !{i32 786443, metadata !5, i32 4, i32 1, metadata !6, i32 0} ; [ DW_TAG_lexical_block ] [/usr/local/google/home/echristo/tmp/bar.c]
+!12 = metadata !{i32 6, i32 3, metadata !11, null}