[DWARF] Use ULEB128 and not just one byte for directory indices #109067

drodriguez · 2024-09-17T23:59:42Z

According to the standard DW_LNCT_directory_index can be data1, data2, or udata (see 6.2.4.1). The code was using data1, but this limits the number of directories to 256, even if the variable holding the directory index is a uint64_t. dsymutil was hitting an assertion when trying to write directory indices higher than 255.

Modify the classic and the parallel DWARF linkers to use udata and encode the directory indices as ULEB128 and provide a test that has more than 256 directories to check the changes are working as expected.

For people that were using dsymutil with CUs that had between 128-256 directories, this will mean that for those indices 2 bytes will be used now, instead of just one.

According to the standard `DW_LNCT_directory_index` can be `data1`, `data2`, or `udata` (see 6.2.4.1). The code was using `data1`, but this limits the number of directories to 256, even if the variable holding the directory index is a `uint64_t`. `dsymutil` was hitting an assertion when trying to write directory indices higher than 255. Modify the classic and the parallel DWARF linkers to use `udata` and encode the directory indices as ULEB128 and provide a test that has more than 256 directories to check the changes are working as expected. For people that were using `dsymutil` with CUs that had between 128-256 directories, this will mean that for those indices 2 bytes will be used now, instead of just one.

llvmbot · 2024-09-18T00:00:16Z

@llvm/pr-subscribers-debuginfo

Author: Daniel Rodríguez Troitiño (drodriguez)

Changes

According to the standard DW_LNCT_directory_index can be data1, data2, or udata (see 6.2.4.1). The code was using data1, but this limits the number of directories to 256, even if the variable holding the directory index is a uint64_t. dsymutil was hitting an assertion when trying to write directory indices higher than 255.

Modify the classic and the parallel DWARF linkers to use udata and encode the directory indices as ULEB128 and provide a test that has more than 256 directories to check the changes are working as expected.

For people that were using dsymutil with CUs that had between 128-256 directories, this will mean that for those indices 2 bytes will be used now, instead of just one.

Patch is 144.49 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/109067.diff

4 Files Affected:

(modified) llvm/lib/DWARFLinker/Classic/DWARFStreamer.cpp (+2-3)
(modified) llvm/lib/DWARFLinker/Parallel/DebugLineSectionEmitter.h (+2-2)
(added) llvm/test/tools/dsymutil/X86/dwarf5-many-include-directories.ll (+2631)
(modified) llvm/test/tools/dsymutil/X86/lit.local.cfg (+1-1)

diff --git a/llvm/lib/DWARFLinker/Classic/DWARFStreamer.cpp b/llvm/lib/DWARFLinker/Classic/DWARFStreamer.cpp
index bca31253683530..947db9cbcd92d0 100644
--- a/llvm/lib/DWARFLinker/Classic/DWARFStreamer.cpp
+++ b/llvm/lib/DWARFLinker/Classic/DWARFStreamer.cpp
@@ -933,7 +933,7 @@ void DwarfStreamer::emitLineTablePrologueV5IncludeAndFileTable(
     LineSectionSize += MS->emitULEB128IntValue(StrForm);
 
     LineSectionSize += MS->emitULEB128IntValue(dwarf::DW_LNCT_directory_index);
-    LineSectionSize += MS->emitULEB128IntValue(dwarf::DW_FORM_data1);
+    LineSectionSize += MS->emitULEB128IntValue(dwarf::DW_FORM_udata);
 
     if (HasChecksums) {
       LineSectionSize += MS->emitULEB128IntValue(dwarf::DW_LNCT_MD5);
@@ -952,8 +952,7 @@ void DwarfStreamer::emitLineTablePrologueV5IncludeAndFileTable(
   // file_names (sequence of file name entries).
   for (auto File : P.FileNames) {
     emitLineTableString(P, File.Name, DebugStrPool, DebugLineStrPool);
-    MS->emitInt8(File.DirIdx);
-    LineSectionSize += 1;
+    LineSectionSize += MS->emitULEB128IntValue(File.DirIdx);
     if (HasChecksums) {
       MS->emitBinaryData(
           StringRef(reinterpret_cast<const char *>(File.Checksum.data()),
diff --git a/llvm/lib/DWARFLinker/Parallel/DebugLineSectionEmitter.h b/llvm/lib/DWARFLinker/Parallel/DebugLineSectionEmitter.h
index 38357c7f97314c..b035c4b1d6c30d 100644
--- a/llvm/lib/DWARFLinker/Parallel/DebugLineSectionEmitter.h
+++ b/llvm/lib/DWARFLinker/Parallel/DebugLineSectionEmitter.h
@@ -215,7 +215,7 @@ class DebugLineSectionEmitter {
       encodeULEB128(FileNameForm, Section.OS);
 
       encodeULEB128(dwarf::DW_LNCT_directory_index, Section.OS);
-      encodeULEB128(dwarf::DW_FORM_data1, Section.OS);
+      encodeULEB128(dwarf::DW_FORM_udata, Section.OS);
 
       if (HasChecksums) {
         encodeULEB128(dwarf::DW_LNCT_MD5, Section.OS);
@@ -242,7 +242,7 @@ class DebugLineSectionEmitter {
       // A null-terminated string containing the full or relative path name of a
       // source file.
       Section.emitString(FileNameForm, *FileNameStr);
-      Section.emitIntVal(File.DirIdx, 1);
+      encodeULEB128(File.DirIdx, Section.OS);
 
       if (HasChecksums) {
         assert((File.Checksum.size() == 16) &&
diff --git a/llvm/test/tools/dsymutil/X86/dwarf5-many-include-directories.ll b/llvm/test/tools/dsymutil/X86/dwarf5-many-include-directories.ll
new file mode 100644
index 00000000000000..74e84e22c03219
--- /dev/null
+++ b/llvm/test/tools/dsymutil/X86/dwarf5-many-include-directories.ll
@@ -0,0 +1,2631 @@
+; RUN: rm -rf %t && mkdir -p %t
+; RUN: %llc_dwarf -o %t/all.o -filetype=obj %s
+; Dummy debug map to get the results. Bare object doesn't seem to work
+; RUN: echo "---" > %t/debug.map
+; RUN: echo "triple: 'x86_64-apple-darwin'" >> %t/debug.map
+; RUN: echo "objects:" >> %t/debug.map
+; RUN: echo "  - filename: %t/all.o" >> %t/debug.map
+; RUN: echo "    symbols:" >> %t/debug.map
+; RUN: echo "      - { sym: _all, objAddr: 0x0, binAddr: 0x0, size: 0x0 }" >> %t/debug.map
+; RUN: echo "..." >> %t/debug.map
+; RUN: dsymutil -f -y %t/debug.map -o - | llvm-dwarfdump -debug-line - | FileCheck %s
+; RUN: dsymutil --linker parallel -f -y %t/debug.map -o - | llvm-dwarfdump -debug-line - | tee %t/output.txt | FileCheck %s
+
+; CHECK:      include_directories[255] = "/tmp/tmp.0HPkdttdoU/d254"
+; CHECK-NEXT: include_directories[256] = "/tmp/tmp.0HPkdttdoU/d255"
+; CHECK-NEXT: include_directories[257] = "/tmp/tmp.0HPkdttdoU/d256"
+
+; CHECK: dir_index: 255
+; CHECK: dir_index: 256
+; CHECK: dir_index: 257
+
+; ---
+; Generated doing (fish shell):
+; - for cnt in (seq 0 256); mkdir -p d$cnt ; printf "void func$cnd() {}\n#define FUNC$cnt func$cnt()\n" >> d$cnt/f$cnt.c ; end
+; - for cnt in (seq 0 256); printf "#include \"f$cnt.c\"" >> all.c ; end
+; - printf "void all() {\n" >> all.c
+; - for cnt in (seq 0 256); printf "FUNC$cnt;\n" >> all.c ; end
+; - printf "}\n" >> all.c
+; - clang -target x86_64-apple-macos -S -emit-llvm -gdwarf-5 -o all.ll all.c (for cnt in (seq 0 256); echo "-Id$cnt"; end)
+; - Edit all.ll manually and change all DIFile so the directory in filename is
+;   moved into the directory field.
+; ---
+; ModuleID = 'all.c'
+source_filename = "all.c"
+target datalayout = "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.4.0"
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func0() #0 !dbg !9 {
+  ret void, !dbg !13
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func1() #0 !dbg !14 {
+  ret void, !dbg !16
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func2() #0 !dbg !17 {
+  ret void, !dbg !19
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func3() #0 !dbg !20 {
+  ret void, !dbg !22
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func4() #0 !dbg !23 {
+  ret void, !dbg !25
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func5() #0 !dbg !26 {
+  ret void, !dbg !28
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func6() #0 !dbg !29 {
+  ret void, !dbg !31
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func7() #0 !dbg !32 {
+  ret void, !dbg !34
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func8() #0 !dbg !35 {
+  ret void, !dbg !37
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func9() #0 !dbg !38 {
+  ret void, !dbg !40
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func10() #0 !dbg !41 {
+  ret void, !dbg !43
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func11() #0 !dbg !44 {
+  ret void, !dbg !46
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func12() #0 !dbg !47 {
+  ret void, !dbg !49
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func13() #0 !dbg !50 {
+  ret void, !dbg !52
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func14() #0 !dbg !53 {
+  ret void, !dbg !55
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func15() #0 !dbg !56 {
+  ret void, !dbg !58
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func16() #0 !dbg !59 {
+  ret void, !dbg !61
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func17() #0 !dbg !62 {
+  ret void, !dbg !64
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func18() #0 !dbg !65 {
+  ret void, !dbg !67
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func19() #0 !dbg !68 {
+  ret void, !dbg !70
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func20() #0 !dbg !71 {
+  ret void, !dbg !73
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func21() #0 !dbg !74 {
+  ret void, !dbg !76
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func22() #0 !dbg !77 {
+  ret void, !dbg !79
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func23() #0 !dbg !80 {
+  ret void, !dbg !82
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func24() #0 !dbg !83 {
+  ret void, !dbg !85
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func25() #0 !dbg !86 {
+  ret void, !dbg !88
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func26() #0 !dbg !89 {
+  ret void, !dbg !91
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func27() #0 !dbg !92 {
+  ret void, !dbg !94
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func28() #0 !dbg !95 {
+  ret void, !dbg !97
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func29() #0 !dbg !98 {
+  ret void, !dbg !100
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func30() #0 !dbg !101 {
+  ret void, !dbg !103
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func31() #0 !dbg !104 {
+  ret void, !dbg !106
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func32() #0 !dbg !107 {
+  ret void, !dbg !109
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func33() #0 !dbg !110 {
+  ret void, !dbg !112
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func34() #0 !dbg !113 {
+  ret void, !dbg !115
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func35() #0 !dbg !116 {
+  ret void, !dbg !118
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func36() #0 !dbg !119 {
+  ret void, !dbg !121
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func37() #0 !dbg !122 {
+  ret void, !dbg !124
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func38() #0 !dbg !125 {
+  ret void, !dbg !127
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func39() #0 !dbg !128 {
+  ret void, !dbg !130
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func40() #0 !dbg !131 {
+  ret void, !dbg !133
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func41() #0 !dbg !134 {
+  ret void, !dbg !136
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func42() #0 !dbg !137 {
+  ret void, !dbg !139
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func43() #0 !dbg !140 {
+  ret void, !dbg !142
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func44() #0 !dbg !143 {
+  ret void, !dbg !145
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func45() #0 !dbg !146 {
+  ret void, !dbg !148
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func46() #0 !dbg !149 {
+  ret void, !dbg !151
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func47() #0 !dbg !152 {
+  ret void, !dbg !154
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func48() #0 !dbg !155 {
+  ret void, !dbg !157
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func49() #0 !dbg !158 {
+  ret void, !dbg !160
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func50() #0 !dbg !161 {
+  ret void, !dbg !163
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func51() #0 !dbg !164 {
+  ret void, !dbg !166
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func52() #0 !dbg !167 {
+  ret void, !dbg !169
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func53() #0 !dbg !170 {
+  ret void, !dbg !172
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func54() #0 !dbg !173 {
+  ret void, !dbg !175
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func55() #0 !dbg !176 {
+  ret void, !dbg !178
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func56() #0 !dbg !179 {
+  ret void, !dbg !181
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func57() #0 !dbg !182 {
+  ret void, !dbg !184
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func58() #0 !dbg !185 {
+  ret void, !dbg !187
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func59() #0 !dbg !188 {
+  ret void, !dbg !190
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func60() #0 !dbg !191 {
+  ret void, !dbg !193
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func61() #0 !dbg !194 {
+  ret void, !dbg !196
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func62() #0 !dbg !197 {
+  ret void, !dbg !199
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func63() #0 !dbg !200 {
+  ret void, !dbg !202
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func64() #0 !dbg !203 {
+  ret void, !dbg !205
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func65() #0 !dbg !206 {
+  ret void, !dbg !208
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func66() #0 !dbg !209 {
+  ret void, !dbg !211
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func67() #0 !dbg !212 {
+  ret void, !dbg !214
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func68() #0 !dbg !215 {
+  ret void, !dbg !217
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func69() #0 !dbg !218 {
+  ret void, !dbg !220
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func70() #0 !dbg !221 {
+  ret void, !dbg !223
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func71() #0 !dbg !224 {
+  ret void, !dbg !226
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func72() #0 !dbg !227 {
+  ret void, !dbg !229
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func73() #0 !dbg !230 {
+  ret void, !dbg !232
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func74() #0 !dbg !233 {
+  ret void, !dbg !235
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func75() #0 !dbg !236 {
+  ret void, !dbg !238
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func76() #0 !dbg !239 {
+  ret void, !dbg !241
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func77() #0 !dbg !242 {
+  ret void, !dbg !244
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func78() #0 !dbg !245 {
+  ret void, !dbg !247
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func79() #0 !dbg !248 {
+  ret void, !dbg !250
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func80() #0 !dbg !251 {
+  ret void, !dbg !253
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func81() #0 !dbg !254 {
+  ret void, !dbg !256
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func82() #0 !dbg !257 {
+  ret void, !dbg !259
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func83() #0 !dbg !260 {
+  ret void, !dbg !262
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func84() #0 !dbg !263 {
+  ret void, !dbg !265
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func85() #0 !dbg !266 {
+  ret void, !dbg !268
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func86() #0 !dbg !269 {
+  ret void, !dbg !271
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func87() #0 !dbg !272 {
+  ret void, !dbg !274
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func88() #0 !dbg !275 {
+  ret void, !dbg !277
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func89() #0 !dbg !278 {
+  ret void, !dbg !280
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func90() #0 !dbg !281 {
+  ret void, !dbg !283
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func91() #0 !dbg !284 {
+  ret void, !dbg !286
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func92() #0 !dbg !287 {
+  ret void, !dbg !289
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func93() #0 !dbg !290 {
+  ret void, !dbg !292
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func94() #0 !dbg !293 {
+  ret void, !dbg !295
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func95() #0 !dbg !296 {
+  ret void, !dbg !298
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func96() #0 !dbg !299 {
+  ret void, !dbg !301
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func97() #0 !dbg !302 {
+  ret void, !dbg !304
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func98() #0 !dbg !305 {
+  ret void, !dbg !307
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func99() #0 !dbg !308 {
+  ret void, !dbg !310
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func100() #0 !dbg !311 {
+  ret void, !dbg !313
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func101() #0 !dbg !314 {
+  ret void, !dbg !316
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func102() #0 !dbg !317 {
+  ret void, !dbg !319
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func103() #0 !dbg !320 {
+  ret void, !dbg !322
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func104() #0 !dbg !323 {
+  ret void, !dbg !325
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func105() #0 !dbg !326 {
+  ret void, !dbg !328
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func106() #0 !dbg !329 {
+  ret void, !dbg !331
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func107() #0 !dbg !332 {
+  ret void, !dbg !334
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func108() #0 !dbg !335 {
+  ret void, !dbg !337
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func109() #0 !dbg !338 {
+  ret void, !dbg !340
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func110() #0 !dbg !341 {
+  ret void, !dbg !343
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func111() #0 !dbg !344 {
+  ret void, !dbg !346
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func112() #0 !dbg !347 {
+  ret void, !dbg !349
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func113() #0 !dbg !350 {
+  ret void, !dbg !352
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func114() #0 !dbg !353 {
+  ret void, !dbg !355
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func115() #0 !dbg !356 {
+  ret void, !dbg !358
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func116() #0 !dbg !359 {
+  ret void, !dbg !361
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func117() #0 !dbg !362 {
+  ret void, !dbg !364
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func118() #0 !dbg !365 {
+  ret void, !dbg !367
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func119() #0 !dbg !368 {
+  ret void, !dbg !370
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func120() #0 !dbg !371 {
+  ret void, !dbg !373
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func121() #0 !dbg !374 {
+  ret void, !dbg !376
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func122() #0 !dbg !377 {
+  ret void, !dbg !379
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func123() #0 !dbg !380 {
+  ret void, !dbg !382
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func124() #0 !dbg !383 {
+  ret void, !dbg !385
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func125() #0 !dbg !386 {
+  ret void, !dbg !388
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func126() #0 !dbg !389 {
+  ret void, !dbg !391
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func127() #0 !dbg !392 {
+  ret void, !dbg !394
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func128() #0 !dbg !395 {
+  ret void, !dbg !397
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func129() #0 !dbg !398 {
+  ret void, !dbg !400
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func130() #0 !dbg !401 {
+  ret void, !dbg !403
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func131() #0 !dbg !404 {
+  ret void, !dbg !406
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func132() #0 !dbg !407 {
+  ret void, !dbg !409
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func133() #0 !dbg !410 {
+  ret void, !dbg !412
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define void @func134() #0 !dbg !413 {
+  ret void, !dbg !415
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define v...
[truncated]

llvm/test/tools/dsymutil/X86/dwarf5-many-include-directories.ll

- Use `.test` as the extension. Remove `.ll` from test extensions. - The output generated by Python is the same, except for the checksum fields, which are constant, but does not seem to matter.

kyulee-com

The code looks good to me!
Thanks for creating a tricky test that requires large files from a script.
While I'm approving this, I would also like to give @JDevlieghere, a chance to review.

JDevlieghere

Given that we know the number of indices, we could always emit the most efficient encoding. That said, we're emitting this only once per line table, so I'm not particularly worried about the additional byte and simplifies the implementation. LGTM.

drodriguez · 2024-09-24T17:54:13Z

Given that we know the number of indices, we could always emit the most efficient encoding. That said, we're emitting this only once per line table, so I'm not particularly worried about the additional byte and simplifies the implementation. LGTM.

I was striving for implementation simplicity. I started to think about a better implementation with different formats, but I did not see clearly how it would be better.

| Range         | data1    | data2     | udata     |
| 0-127         | 1 byte * | 2 bytes   | 1 byte *  |
| 128-255       | 1 byte * | 2 bytes   | 2 bytes   |
| 255-16383     | NA       | 2 bytes * | 2 bytes * |
| 16384-65535   | NA       | 2 bytes * | 3 bytes   |
| 65536-2097151 | NA       | NA        | 3 bytes * |

One thing to notice is that one can use the range to choose a format, and that works for getting the best format for 0-16383, but for 16384-65536, one needs to calculate the distribution of indices to see if the udata encoding or the data2 encoding will be smaller.

…#109067) According to the standard `DW_LNCT_directory_index` can be `data1`, `data2`, or `udata` (see 6.2.4.1). The code was using `data1`, but this limits the number of directories to 256, even if the variable holding the directory index is a `uint64_t`. `dsymutil` was hitting an assertion when trying to write directory indices higher than 255. Modify the classic and the parallel DWARF linkers to use `udata` and encode the directory indices as ULEB128 and provide a test that has more than 256 directories to check the changes are working as expected. For people that were using `dsymutil` with CUs that had between 128-256 directories, this will mean that for those indices 2 bytes will be used now, instead of just one.

drodriguez requested a review from JDevlieghere as a code owner September 17, 2024 23:59

llvmbot added the debuginfo label Sep 17, 2024

ellishg reviewed Sep 18, 2024

View reviewed changes

llvm/test/tools/dsymutil/X86/dwarf5-many-include-directories.ll Outdated Show resolved Hide resolved

llvm/test/tools/dsymutil/X86/dwarf5-many-include-directories.ll Outdated Show resolved Hide resolved

drodriguez added 3 commits September 18, 2024 14:25

Remake the test in Python to avoid large test.

d3f62ef

- Use `.test` as the extension. Remove `.ll` from test extensions. - The output generated by Python is the same, except for the checksum fields, which are constant, but does not seem to matter.

Make sed regex compatible with Windows.

70f444d

Force use of Mach-O format for dsymutil, even on Windows

be20162

drodriguez requested review from clayborg and kyulee-com September 24, 2024 00:44

kyulee-com approved these changes Sep 24, 2024

View reviewed changes

JDevlieghere approved these changes Sep 24, 2024

View reviewed changes

drodriguez merged commit 12285cc into llvm:main Sep 24, 2024
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[DWARF] Use ULEB128 and not just one byte for directory indices #109067

[DWARF] Use ULEB128 and not just one byte for directory indices #109067

drodriguez commented Sep 17, 2024

llvmbot commented Sep 18, 2024

kyulee-com left a comment

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drodriguez commented Sep 24, 2024

[DWARF] Use ULEB128 and not just one byte for directory indices #109067

[DWARF] Use ULEB128 and not just one byte for directory indices #109067

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drodriguez commented Sep 17, 2024

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drodriguez commented Sep 24, 2024