[llvm] r340878 - [codeview] Emit labels for .cv_loc immediately

Reid Kleckner via llvm-commits llvm-commits at lists.llvm.org
Tue Aug 28 15:29:12 PDT 2018


Author: rnk
Date: Tue Aug 28 15:29:12 2018
New Revision: 340878

URL: http://llvm.org/viewvc/llvm-project?rev=340878&view=rev
Log:
[codeview] Emit labels for .cv_loc immediately

Previously we followed the DWARF implementation, which waits until the
next instruction or data to emit the label to use in the .debug_loc
section. We might want to consider re-evaluating that design choice as
well, since it means the .loc skips alignment padding, for better or
worse.

This was the most minimal fix I could come up with, but we should be
able to do a lot of cleanups now that we don't need to save a pending CV
location on the CodeViewContext. I plan to do those next, but this
immediately fixes an assertion for some of our users.

Added:
    llvm/trunk/test/MC/COFF/cv-loc-unreachable-2.s
Modified:
    llvm/trunk/lib/MC/MCObjectStreamer.cpp
    llvm/trunk/test/MC/COFF/cv-loc-unreachable.s

Modified: llvm/trunk/lib/MC/MCObjectStreamer.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCObjectStreamer.cpp?rev=340878&r1=340877&r2=340878&view=diff
==============================================================================
--- llvm/trunk/lib/MC/MCObjectStreamer.cpp (original)
+++ llvm/trunk/lib/MC/MCObjectStreamer.cpp Tue Aug 28 15:29:12 2018
@@ -446,12 +446,12 @@ void MCObjectStreamer::EmitCVLocDirectiv
                                           unsigned Line, unsigned Column,
                                           bool PrologueEnd, bool IsStmt,
                                           StringRef FileName, SMLoc Loc) {
-  // In case we see two .cv_loc directives in a row, make sure the
-  // first one gets a line entry.
-  MCCVLineEntry::Make(this);
-
+  // Unlike dwarf locations, we don't save the MCCVLineEntry until the next
+  // instruction. We create the label exactly where the directive appears in the
+  // assembly.
   this->MCStreamer::EmitCVLocDirective(FunctionId, FileNo, Line, Column,
                                        PrologueEnd, IsStmt, FileName, Loc);
+  MCCVLineEntry::Make(this);
 }
 
 void MCObjectStreamer::EmitCVLinetableDirective(unsigned FunctionId,

Added: llvm/trunk/test/MC/COFF/cv-loc-unreachable-2.s
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/COFF/cv-loc-unreachable-2.s?rev=340878&view=auto
==============================================================================
--- llvm/trunk/test/MC/COFF/cv-loc-unreachable-2.s (added)
+++ llvm/trunk/test/MC/COFF/cv-loc-unreachable-2.s Tue Aug 28 15:29:12 2018
@@ -0,0 +1,175 @@
+# RUN: llvm-mc < %s -triple=i686-pc-win32 -filetype=obj | llvm-readobj - -codeview | FileCheck %s
+
+# Based on the other cv-loc-unreachable-2.s, but with other code in the same
+# section afterwards. We had negative label difference assertions when .cv_loc
+# bound tightly to the next instruction.
+
+# CHECK-LABEL: InlineeSourceLine {
+# CHECK:   Inlinee: do_exit (0x1002)
+# CHECK:   FileID: C:\src\llvm-project\build\t.cpp (0x0)
+# CHECK:   SourceLineNum: 3
+# CHECK: }
+
+# CHECK-LABEL: InlineSiteSym {
+# CHECK:   Kind: S_INLINESITE (0x114D)
+# CHECK:   Inlinee: do_exit (0x1002)
+# CHECK:   BinaryAnnotations [
+# CHECK-NEXT:     ChangeLineOffset: 1
+# CHECK-NEXT:     ChangeCodeLength: 0x9
+# CHECK-NEXT:     ChangeCodeOffsetAndLineOffset: {CodeOffset: 0x1, LineOffset: 1}
+# CHECK-NEXT:     ChangeCodeOffsetAndLineOffset: {CodeOffset: 0x8, LineOffset: 1}
+# CHECK-NEXT:     ChangeCodeLength: 0x0
+# CHECK-NEXT:   ]
+# CHECK: }
+
+	.text
+	.def	 _callit; .scl	2; .type	32; .endef
+	.globl	_callit                 # -- Begin function callit
+_callit:                                # @callit
+Lfunc_begin0:
+	.cv_func_id 0
+	.cv_fpo_proc	_callit 0
+# %bb.0:                                # %entry
+	.cv_file	1 "C:\\src\\llvm-project\\build\\t.cpp" "0BC092F354CE14FDC2FA78F8EDE7426E" 1
+	.cv_inline_site_id 1 within 0 inlined_at 1 9 0
+	.cv_loc	1 1 4 0 is_stmt 0       # t.cpp:4:0
+	calll	_unlikely
+	testl	%eax, %eax
+	jne	LBB0_1
+Ltmp0:
+# %bb.2:                                # %do_exit.exit
+	.cv_loc	0 1 10 0                # t.cpp:10:0
+	retl
+LBB0_1:                                 # %if.then.i
+Ltmp1:
+	.cv_loc	1 1 5 0                 # t.cpp:5:0
+	pushl	$32
+	calll	*__imp__exit
+	# EXTRA
+	.cv_loc	1 1 6 0                 # t.cpp:6:0
+Ltmp2:
+	.cv_fpo_endproc
+Lfunc_end0:
+                                        # -- End function
+
+	.text
+	.align 32
+	retl
+
+	.section	.debug$S,"dr"
+	.p2align	2
+	.long	4                       # Debug section magic
+	.long	241
+	.long	Ltmp4-Ltmp3             # Subsection size
+Ltmp3:
+	.short	Ltmp6-Ltmp5             # Record length
+Ltmp5:
+	.short	4412                    # Record kind: S_COMPILE3
+	.long	0                       # Flags and language
+	.short	7                       # CPUType
+	.short	7                       # Frontend version
+	.short	0
+	.short	0
+	.short	0
+	.short	7000                    # Backend version
+	.short	0
+	.short	0
+	.short	0
+	.asciz	"clang version 7.0.0 "  # Null-terminated compiler version string
+Ltmp6:
+Ltmp4:
+	.p2align	2
+	.long	246                     # Inlinee lines subsection
+	.long	Ltmp8-Ltmp7             # Subsection size
+Ltmp7:
+	.long	0                       # Inlinee lines signature
+
+                                        # Inlined function do_exit starts at t.cpp:3
+	.long	4098                    # Type index of inlined function
+	.cv_filechecksumoffset	1       # Offset into filechecksum table
+	.long	3                       # Starting line number
+Ltmp8:
+	.p2align	2
+	.cv_fpo_data	_callit
+	.long	241                     # Symbol subsection for callit
+	.long	Ltmp10-Ltmp9            # Subsection size
+Ltmp9:
+	.short	Ltmp12-Ltmp11           # Record length
+Ltmp11:
+	.short	4423                    # Record kind: S_GPROC32_ID
+	.long	0                       # PtrParent
+	.long	0                       # PtrEnd
+	.long	0                       # PtrNext
+	.long	Lfunc_end0-_callit      # Code size
+	.long	0                       # Offset after prologue
+	.long	0                       # Offset before epilogue
+	.long	4099                    # Function type index
+	.secrel32	_callit         # Function section relative address
+	.secidx	_callit                 # Function section index
+	.byte	0                       # Flags
+	.asciz	"callit"                # Function name
+Ltmp12:
+	.short	Ltmp14-Ltmp13           # Record length
+Ltmp13:
+	.short	4429                    # Record kind: S_INLINESITE
+	.long	0                       # PtrParent
+	.long	0                       # PtrEnd
+	.long	4098                    # Inlinee type index
+	.cv_inline_linetable	1 1 3 Lfunc_begin0 Lfunc_end0
+Ltmp14:
+	.short	2                       # Record length
+	.short	4430                    # Record kind: S_INLINESITE_END
+	.short	2                       # Record length
+	.short	4431                    # Record kind: S_PROC_ID_END
+Ltmp10:
+	.p2align	2
+	.cv_linetable	0, _callit, Lfunc_end0
+	.cv_filechecksums               # File index to string table offset subsection
+	.cv_stringtable                 # String table
+	.section	.debug$T,"dr"
+	.p2align	2
+	.long	4                       # Debug section magic
+	# ArgList (0x1000) {
+	#   TypeLeafKind: LF_ARGLIST (0x1201)
+	#   NumArgs: 0
+	#   Arguments [
+	#   ]
+	# }
+	.byte	0x06, 0x00, 0x01, 0x12
+	.byte	0x00, 0x00, 0x00, 0x00
+	# Procedure (0x1001) {
+	#   TypeLeafKind: LF_PROCEDURE (0x1008)
+	#   ReturnType: void (0x3)
+	#   CallingConvention: NearC (0x0)
+	#   FunctionOptions [ (0x0)
+	#   ]
+	#   NumParameters: 0
+	#   ArgListType: () (0x1000)
+	# }
+	.byte	0x0e, 0x00, 0x08, 0x10
+	.byte	0x03, 0x00, 0x00, 0x00
+	.byte	0x00, 0x00, 0x00, 0x00
+	.byte	0x00, 0x10, 0x00, 0x00
+	# FuncId (0x1002) {
+	#   TypeLeafKind: LF_FUNC_ID (0x1601)
+	#   ParentScope: 0x0
+	#   FunctionType: void () (0x1001)
+	#   Name: do_exit
+	# }
+	.byte	0x12, 0x00, 0x01, 0x16
+	.byte	0x00, 0x00, 0x00, 0x00
+	.byte	0x01, 0x10, 0x00, 0x00
+	.byte	0x64, 0x6f, 0x5f, 0x65
+	.byte	0x78, 0x69, 0x74, 0x00
+	# FuncId (0x1003) {
+	#   TypeLeafKind: LF_FUNC_ID (0x1601)
+	#   ParentScope: 0x0
+	#   FunctionType: void () (0x1001)
+	#   Name: callit
+	# }
+	.byte	0x12, 0x00, 0x01, 0x16
+	.byte	0x00, 0x00, 0x00, 0x00
+	.byte	0x01, 0x10, 0x00, 0x00
+	.byte	0x63, 0x61, 0x6c, 0x6c
+	.byte	0x69, 0x74, 0x00, 0xf1
+

Modified: llvm/trunk/test/MC/COFF/cv-loc-unreachable.s
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/COFF/cv-loc-unreachable.s?rev=340878&r1=340877&r2=340878&view=diff
==============================================================================
--- llvm/trunk/test/MC/COFF/cv-loc-unreachable.s (original)
+++ llvm/trunk/test/MC/COFF/cv-loc-unreachable.s Tue Aug 28 15:29:12 2018
@@ -14,9 +14,6 @@
 #   do_exit();
 # }
 
-# We should *not* see t.cpp:6 in the inline line table because we change
-# sections before the next instruction. We should only see t.cpp:5.
-
 # CHECK-LABEL: InlineeSourceLine {
 # CHECK:   Inlinee: do_exit (0x1002)
 # CHECK:   FileID: C:\src\llvm-project\build\t.cpp (0x0)
@@ -30,7 +27,8 @@
 # CHECK-NEXT:     ChangeLineOffset: 1
 # CHECK-NEXT:     ChangeCodeLength: 0x9
 # CHECK-NEXT:     ChangeCodeOffsetAndLineOffset: {CodeOffset: 0x1, LineOffset: 1}
-# CHECK-NEXT:     ChangeCodeLength: 0x8
+# CHECK-NEXT:     ChangeCodeOffsetAndLineOffset: {CodeOffset: 0x8, LineOffset: 1}
+# CHECK-NEXT:     ChangeCodeLength: 0x0
 # CHECK-NEXT:   ]
 # CHECK: }
 




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