[ELF] Add .eh_frame pieces to map file

This patch is a simplified version of https://reviews.llvm.org/D42960 written by Andrew Ng. Differential Revision: https://reviews.llvm.org/D44168 llvm-svn: 327574
llvm · Mar 14, 2018 · a5c1ed3 · a5c1ed3
1 parent 6366efe
commit a5c1ed3
Show file tree

Hide file tree

Showing 4 changed files with 52 additions and 3 deletions.
diff --git a/lld/ELF/MapFile.cpp b/lld/ELF/MapFile.cpp
@@ -112,6 +112,43 @@ getSymbolStrings(ArrayRef<Symbol *> Syms) {
   return Ret;
 }
 
+// Print .eh_frame contents. Since the section consists of EhSectionPieces,
+// we need a specialized printer for that section.
+//
+// .eh_frame tend to contain a lot of section pieces that are contiguous
+// both in input file and output file. Such pieces are squashed before
+// being displayed to make output compact.
+static void printEhFrame(raw_ostream &OS, OutputSection *OSec) {
+  std::vector<EhSectionPiece> Pieces;
+
+  auto Add = [&](const EhSectionPiece &P) {
+    // If P is adjacent to Last, squash the two.
+    if (!Pieces.empty()) {
+      EhSectionPiece &Last = Pieces.back();
+      if (Last.Sec == P.Sec && Last.InputOff + Last.Size == P.InputOff &&
+          Last.OutputOff + Last.Size == P.OutputOff) {
+        Last.Size += P.Size;
+        return;
+      }
+    }
+    Pieces.push_back(P);
+  };
+
+  // Gather section pieces.
+  for (const CieRecord *Rec : InX::EhFrame->getCieRecords()) {
+    Add(*Rec->Cie);
+    for (const EhSectionPiece *Fde : Rec->Fdes)
+      Add(*Fde);
+  }
+
+  // Print out section pieces.
+  for (EhSectionPiece &P : Pieces) {
+    writeHeader(OS, OSec->Addr + P.OutputOff, P.Size, 0);
+    OS << Indent8 << toString(P.Sec->File) << ":(" << P.Sec->Name << "+0x"
+       << Twine::utohexstr(P.InputOff) + ")\n";
+  }
+}
+
 void elf::writeMapFile() {
   if (Config->MapFile.empty())
     return;
@@ -141,6 +178,11 @@ void elf::writeMapFile() {
 
     // Dump symbols for each input section.
     for (InputSection *IS : getInputSections(OSec)) {
+      if (IS == InX::EhFrame) {
+        printEhFrame(OS, OSec);
+        continue;
+      }
+
       writeHeader(OS, OSec->Addr + IS->OutSecOff, IS->getSize(), IS->Alignment);
       OS << Indent8 << toString(IS) << '\n';
       for (Symbol *Sym : SectionSyms[IS])

diff --git a/lld/ELF/SyntheticSections.h b/lld/ELF/SyntheticSections.h
@@ -83,6 +83,7 @@ class EhFrameSection final : public SyntheticSection {
   };
 
   std::vector<FdeData> getFdeData() const;
+  ArrayRef<CieRecord *> getCieRecords() const { return CieRecords; }
 
 private:
   uint64_t Size = 0;

diff --git a/lld/test/ELF/Inputs/map-file2.s b/lld/test/ELF/Inputs/map-file2.s
@@ -1,5 +1,7 @@
 foo:
+.cfi_startproc
 nop
+.cfi_endproc
 .global bar
 bar:
 nop

diff --git a/lld/test/ELF/map-file.s b/lld/test/ELF/map-file.s
@@ -15,6 +15,8 @@
 
 .global _start
 _start:
+.cfi_startproc
+.cfi_endproc
  .quad sharedFoo
  .quad sharedBar
  .byte 0xe8
@@ -26,8 +28,8 @@ _start:
 .global _Z1fi
 _Z1fi:
 .cfi_startproc
-.cfi_endproc
 nop
+.cfi_endproc
 .weak bar
 bar:
 .long bar - .
@@ -51,8 +53,10 @@ labs = 0x1AB5
 // CHECK-NEXT: 00000000002002d0 0000000000000030     8         <internal>:(.rela.dyn)
 // CHECK-NEXT: 0000000000200300 0000000000000030     8 .rela.plt
 // CHECK-NEXT: 0000000000200300 0000000000000030     8         <internal>:(.rela.plt)
-// CHECK-NEXT: 0000000000200330 0000000000000030     8 .eh_frame
-// CHECK-NEXT: 0000000000200330 0000000000000030     8         <internal>:(.eh_frame)
+// CHECK-NEXT: 0000000000200330 0000000000000060     8 .eh_frame
+// CHECK-NEXT: 0000000000200330 000000000000002c     0         {{.*}}{{/|\\}}map-file.s.tmp1.o:(.eh_frame+0x0)
+// CHECK-NEXT: 0000000000200360 0000000000000014     0         {{.*}}{{/|\\}}map-file.s.tmp1.o:(.eh_frame+0x2c)
+// CHECK-NEXT: 0000000000200378 0000000000000018     0         {{.*}}{{/|\\}}map-file.s.tmp2.o:(.eh_frame+0x18)
 // CHECK-NEXT: 0000000000201000 000000000000002d     4 .text
 // CHECK-NEXT: 0000000000201000 0000000000000028     4         {{.*}}{{/|\\}}map-file.s.tmp1.o:(.text)
 // CHECK-NEXT: 0000000000201000 0000000000000000     0                 _start