[ARM][Debug Info] Restore emitting of .cfi_def_cfa_offset for functions without stack frame

Sergey Dmitrouk · Sergey Dmitrouk · commit 3cc62b371502 · 2015-04-08T10:10:12.000Z
Summary: Looks like new code from [[ http://reviews.llvm.org/rL222057 | rL222057 ]] doesn't account for early `return` in `ARMFrameLowering::emitPrologue`, which leads to loosing `.cfi_def_cfa_offset` directive for functions without stack frame. Reviewers: echristo, rengolin, asl, t.p.northover Reviewed By: t.p.northover Subscribers: llvm-commits, rengolin, aemerson Differential Revision: http://reviews.llvm.org/D8606 llvm-svn: 234399
diff --git a/llvm/lib/Target/ARM/ARMFrameLowering.cpp b/llvm/lib/Target/ARM/ARMFrameLowering.cpp
@@ -311,6 +311,7 @@ void ARMFrameLowering::emitPrologue(MachineFunction &MF) const {
     return;
 
   StackAdjustingInsts DefCFAOffsetCandidates;
+  bool HasFP = hasFP(MF);
 
   // Allocate the vararg register save area.
   if (ArgRegsSaveSize) {
@@ -327,6 +328,7 @@ void ARMFrameLowering::emitPrologue(MachineFunction &MF) const {
       DefCFAOffsetCandidates.addInst(std::prev(MBBI),
                                      NumBytes - ArgRegsSaveSize, true);
     }
+    DefCFAOffsetCandidates.emitDefCFAOffsets(MMI, MBB, dl, TII, HasFP);
     return;
   }
 
@@ -375,7 +377,6 @@ void ARMFrameLowering::emitPrologue(MachineFunction &MF) const {
   }
 
   // Determine starting offsets of spill areas.
-  bool HasFP = hasFP(MF);
   unsigned GPRCS1Offset = NumBytes - ArgRegsSaveSize - GPRCS1Size;
   unsigned GPRCS2Offset = GPRCS1Offset - GPRCS2Size;
   unsigned DPRAlign = DPRCSSize ? std::min(8U, Align) : 4U;
diff --git a/llvm/test/CodeGen/ARM/debug-info-no-frame.ll b/llvm/test/CodeGen/ARM/debug-info-no-frame.ll
@@ -0,0 +1,36 @@
+; RUN: llc -mtriple=armv7-none-linux-gnueabihf < %s -o - | FileCheck %s
+
+; Function Attrs: nounwind
+define void @need_cfi_def_cfa_offset() #0 {
+; CHECK-LABEL: need_cfi_def_cfa_offset:
+; CHECK: sub	sp, sp, #4
+; CHECK: .cfi_def_cfa_offset 4
+entry:
+  %Depth = alloca i32, align 4
+  call void @llvm.dbg.declare(metadata i32* %Depth, metadata !9, metadata !10), !dbg !11
+  store i32 2, i32* %Depth, align 4, !dbg !11
+  ret void, !dbg !12
+}
+
+; Function Attrs: nounwind readnone
+declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
+
+attributes #0 = { nounwind }
+attributes #1 = { nounwind readnone }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!7, !8}
+
+!0 = !MDCompileUnit(language: DW_LANG_C99, file: !1, producer: "", isOptimized: false)
+!1 = !MDFile(filename: "file.c", directory: "/dir")
+!2 = !{}
+!3 = !MDSubprogram(name: "need_cfi_def_cfa_offset", scope: !1, file: !1, line: 1, type: !4, isLocal: false, isDefinition: true, scopeLine: 2, isOptimized: false, function: void ()* @need_cfi_def_cfa_offset, variables: !2)
+!4 = !MDSubroutineType(types: !5)
+!5 = !{null}
+!6 = !MDBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
+!7 = !{i32 2, !"Dwarf Version", i32 4}
+!8 = !{i32 2, !"Debug Info Version", i32 3}
+!9 = !MDLocalVariable(tag: DW_TAG_auto_variable, name: "Depth", scope: !3, file: !1, line: 3, type: !6)
+!10 = !MDExpression()
+!11 = !MDLocation(line: 3, column: 9, scope: !3)
+!12 = !MDLocation(line: 7, column: 5, scope: !3)

Original file line number	Diff line number	Diff line change
`@@ -311,6 +311,7 @@ void ARMFrameLowering::emitPrologue(MachineFunction &MF) const {`
`311`	`311`	`return;`
`312`	`312`
`313`	`313`	`StackAdjustingInsts DefCFAOffsetCandidates;`
	`314`	`+ bool HasFP = hasFP(MF);`
`314`	`315`
`315`	`316`	`// Allocate the vararg register save area.`
`316`	`317`	`if (ArgRegsSaveSize) {`
`@@ -327,6 +328,7 @@ void ARMFrameLowering::emitPrologue(MachineFunction &MF) const {`
`327`	`328`	`DefCFAOffsetCandidates.addInst(std::prev(MBBI),`
`328`	`329`	`NumBytes - ArgRegsSaveSize, true);`
`329`	`330`	`}`
	`331`	`+ DefCFAOffsetCandidates.emitDefCFAOffsets(MMI, MBB, dl, TII, HasFP);`
`330`	`332`	`return;`
`331`	`333`	`}`
`332`	`334`
`@@ -375,7 +377,6 @@ void ARMFrameLowering::emitPrologue(MachineFunction &MF) const {`
`375`	`377`	`}`
`376`	`378`
`377`	`379`	`// Determine starting offsets of spill areas.`
`378`		`- bool HasFP = hasFP(MF);`
`379`	`380`	`unsigned GPRCS1Offset = NumBytes - ArgRegsSaveSize - GPRCS1Size;`
`380`	`381`	`unsigned GPRCS2Offset = GPRCS1Offset - GPRCS2Size;`
`381`	`382`	`unsigned DPRAlign = DPRCSSize ? std::min(8U, Align) : 4U;`