From 3d381a710220100722465ead9c64874621edead4 Mon Sep 17 00:00:00 2001
From: Francis Visoiu Mistrih <francisvm@yahoo.com>
Date: Fri, 4 Dec 2020 20:10:06 -0800
Subject: [PATCH] [llvm-nm][MachO] Don't call getFlags on redacted symbols

Avoid calling getFlags on a non-existent symbol.

The way this is triggered is by calling strip -N on a binary, which sets
the MH_NLIST_OUTOFSYNC_WITH_DYLDINFO header flag. Then, in the
LC_FUNCTION_STARTS command, nm is trying to print the stripped symbols
and needs the proper checks.
---
 .../Inputs/redacted-function.macho-aarch64      | Bin 0 -> 32820 bytes
 .../AArch64/macho-redacted-function.test        |  16 ++++++++++++++++
 llvm/tools/llvm-nm/llvm-nm.cpp                  |  14 ++++++++------
 3 files changed, 24 insertions(+), 6 deletions(-)
 create mode 100755 llvm/test/tools/llvm-nm/AArch64/Inputs/redacted-function.macho-aarch64
 create mode 100644 llvm/test/tools/llvm-nm/AArch64/macho-redacted-function.test

diff --git a/llvm/test/tools/llvm-nm/AArch64/Inputs/redacted-function.macho-aarch64 b/llvm/test/tools/llvm-nm/AArch64/Inputs/redacted-function.macho-aarch64
new file mode 100755
index 0000000000000000000000000000000000000000..eebb208b421cf20b4214f7a7ef6953350e1a5dd3
GIT binary patch
literal 32820
zcmeI*KWkG_7{~D^X^KUII&=^eP5p;TX+$~*I;3ilqG*X7#O08hD-ARe+5}rV7%=V@
zT%=GOEjZN8tpRtz#dqNw5Mup3xw$4*aB`CGf#;s{+<WfHIiH*T`TYIckE~fbWx6Pi
zDBf%E(sCKUcU2L>+|2Fbqhjg4lB5-q!Joaq*HMHpUwk+}^t_;PtDmbM)zHI#*INjU
zXtfcK<NWvc+q-6ydeDA8c&9fz^J`VD(X2nK)+?b}fAUlh_wQjxYs~5X&i*xe3&oeg
zx$n;2yHmV1o1CFzHtkbdaqsgyl6G28E+@&~`c`}nKld@kv~q7re@J8B<G*T$wa^KL
zzO&_<E6e$%>O#J<wp3AmT;Y3owVB&`bA9^E?!oTn*0qywujpP*kx`f(=!Ktk#8WG$
zFX?);H;ykCbar3Izs+!)P%`c}3jI*$`*25}AAkF-{syVR-n735Yb%YYHg#i4`>ZaQ
zo!4Cdy~&o@nEH$TJTX&BLjVB;5I_I{1Q0*~0R#|0009ILKmY**5I_I{1Q0*~0R#|0
z009ILKmY**5I_I{1Q0*~0R#|0009ILKmY**5I_I{1Q0*~0R#|0009ILKmY**5I_I{
z1Q0*~0R#|0009ILKmY**5I_I{1Q0*~0R#|0009ILKmY**5I_I{1Q0*~0R#|0009IL
zKmY**5I_I{1Q0*~f&V~Y?}dHouBW!UH*I6gTBUcNPJL9}_1E3?nQcAW=!}G~Dz9Gh
z-fOUXEq8Cjz1LCq+Us6d-Qz>Q4!e)NW_wnZ*2m*&>#4KK)%=x=rGkxGI@A_Jv>H8b
cHlnZ?l`GM*P1MTOx}A$>wfFSHy7XTC2@Aqy_5c6?

literal 0
HcmV?d00001

diff --git a/llvm/test/tools/llvm-nm/AArch64/macho-redacted-function.test b/llvm/test/tools/llvm-nm/AArch64/macho-redacted-function.test
new file mode 100644
index 00000000000000..c662f54c93b6cc
--- /dev/null
+++ b/llvm/test/tools/llvm-nm/AArch64/macho-redacted-function.test
@@ -0,0 +1,16 @@
+RUN: llvm-nm %p/Inputs/redacted-function.macho-aarch64 | FileCheck %s
+
+CHECK: <redacted function 1>
+
+# Generated with:
+# $ cat /tmp/a.c
+# static int i(void) {
+#   return 0;
+# }
+#
+# int main(void) {
+#   return i();
+# }
+#
+# $ xcrun -sdk watchos clang -arch arm64_32 /tmp/a.c -o /tmp/redacted-function.macho-aarch64
+# $ xcrun -sdk watchos strip -N /tmp/redacted-function.macho-aarch64
diff --git a/llvm/tools/llvm-nm/llvm-nm.cpp b/llvm/tools/llvm-nm/llvm-nm.cpp
index a34352d1512c5f..9680149d4f8cf3 100644
--- a/llvm/tools/llvm-nm/llvm-nm.cpp
+++ b/llvm/tools/llvm-nm/llvm-nm.cpp
@@ -316,18 +316,20 @@ struct NMSymbol {
 static bool compareSymbolAddress(const NMSymbol &A, const NMSymbol &B) {
   bool ADefined;
   // Symbol flags have been checked in the caller.
-  uint32_t AFlags = cantFail(A.Sym.getFlags());
-  if (A.Sym.getRawDataRefImpl().p)
+  if (A.Sym.getRawDataRefImpl().p) {
+    uint32_t AFlags = cantFail(A.Sym.getFlags());
     ADefined = !(AFlags & SymbolRef::SF_Undefined);
-  else
+  } else {
     ADefined = A.TypeChar != 'U';
+  }
   bool BDefined;
   // Symbol flags have been checked in the caller.
-  uint32_t BFlags = cantFail(B.Sym.getFlags());
-  if (B.Sym.getRawDataRefImpl().p)
+  if (B.Sym.getRawDataRefImpl().p) {
+    uint32_t BFlags = cantFail(B.Sym.getFlags());
     BDefined = !(BFlags & SymbolRef::SF_Undefined);
-  else
+  } else {
     BDefined = B.TypeChar != 'U';
+  }
   return std::make_tuple(ADefined, A.Address, A.Name, A.Size) <
          std::make_tuple(BDefined, B.Address, B.Name, B.Size);
 }