From c8b082a3abe44138fff4ef824300270dd6e8bc77 Mon Sep 17 00:00:00 2001
From: Fangrui Song <maskray@google.com>
Date: Wed, 17 Jun 2020 10:17:15 -0700
Subject: [PATCH] [llvm-cov gcov] Support clang<11 fake 4.2 format

Test cases are restored from a3bed4bd3743b5fee1e66116a63089df742bcae1
---
 llvm/lib/ProfileData/GCOV.cpp                 |  16 +++++--
 .../tools/llvm-cov/Inputs/gcov-fake-4.2.gcda  | Bin 0 -> 904 bytes
 .../tools/llvm-cov/Inputs/gcov-fake-4.2.gcno  | Bin 0 -> 3552 bytes
 llvm/test/tools/llvm-cov/gcov-fake-4.2.c      |  39 ++++++++++++++++++
 4 files changed, 51 insertions(+), 4 deletions(-)
 create mode 100644 llvm/test/tools/llvm-cov/Inputs/gcov-fake-4.2.gcda
 create mode 100644 llvm/test/tools/llvm-cov/Inputs/gcov-fake-4.2.gcno
 create mode 100644 llvm/test/tools/llvm-cov/gcov-fake-4.2.c

diff --git a/llvm/lib/ProfileData/GCOV.cpp b/llvm/lib/ProfileData/GCOV.cpp
index 35d40db11716..71ea44a1a722 100644
--- a/llvm/lib/ProfileData/GCOV.cpp
+++ b/llvm/lib/ProfileData/GCOV.cpp
@@ -175,16 +175,24 @@ bool GCOVFile::readGCDA(GCOVBuffer &buf) {
     if (tag == GCOV_TAG_OBJECT_SUMMARY) {
       buf.readInt(RunCount);
       buf.readInt(dummy);
+      // clang<11 uses a fake 4.2 format which sets length to 9.
+      if (length == 9)
+        buf.readInt(RunCount);
     } else if (tag == GCOV_TAG_PROGRAM_SUMMARY) {
-      buf.readInt(dummy);
-      buf.readInt(dummy);
-      buf.readInt(RunCount);
+      // clang<11 uses a fake 4.2 format which sets length to 0.
+      if (length > 0) {
+        buf.readInt(dummy);
+        buf.readInt(dummy);
+        buf.readInt(RunCount);
+      }
       ++ProgramCount;
     } else if (tag == GCOV_TAG_FUNCTION) {
       if (length == 0) // Placeholder
         continue;
       // As of GCC 10, GCOV_TAG_FUNCTION_LENGTH has never been larger than 3.
-      if ((length != 2 && length != 3) || !buf.readInt(ident))
+      // However, clang<11 uses a fake 4.2 format which may set length larger
+      // than 3.
+      if (length < 2 || !buf.readInt(ident))
         return false;
       auto It = IdentToFunction.find(ident);
       uint32_t linenoChecksum, cfgChecksum = 0;
diff --git a/llvm/test/tools/llvm-cov/Inputs/gcov-fake-4.2.gcda b/llvm/test/tools/llvm-cov/Inputs/gcov-fake-4.2.gcda
new file mode 100644
index 0000000000000000000000000000000000000000..613e3a85c02678566e12df9cf0487adea393c222
GIT binary patch
literal 904
zcmYdHNlw=?GB7cSb5LYpU|?he5+ERVLR^CxNXJL{89Ev|xt4)N7c#PdX$A%+R2r<0
z5h!+iWA-A5KJ(Jz)ST4fVvtURKBzVr#mE6<fy|nuFMWm;NXJJR8s+8}rN$%a#-|^o
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z4VFR@N9T(`1z_sY-GHthmd4QC1`~(rhnWkbVdjI(1F_NhSj55c1~PBj;fILy>}-gV
oo?+&|XrOYiK2Y2p{!%jso)4Uj2<cl0(gOoX=D~!J>BYz#0O(&w6aWAK

literal 0
HcmV?d00001

diff --git a/llvm/test/tools/llvm-cov/Inputs/gcov-fake-4.2.gcno b/llvm/test/tools/llvm-cov/Inputs/gcov-fake-4.2.gcno
new file mode 100644
index 0000000000000000000000000000000000000000..24f1c82476b2cc2cbab056e962a919771042cdd7
GIT binary patch
literal 3552
zcmd5<J8u&~5WeG0FmFUaKturX2;f(oMB=45<`5M>zy+2`j5(3mmd^wU@hd2(s3@qA
z5H%7_3Mlv!{D)Lfz<fKNz4P2!GLmI6((UcceLM5r?986sZml-wiuqFh@$#(adHw+!
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z51*m1{`*-t%g*{EpPLc`Jd$U%3oCii*b5H7@{XfmC4U-w(cxF}sj)5&vL71j@+<k*
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zm;DnPIBOep**o!@ta*I9SSqG(v3F9xvNw`<xl3*(E^u+r$GxF#Sf_1>rESpTZ!G(R
zo_r6yE4cG_lqUV0L6`5`QJ9Ue57>|NEy5jo(g*xv9e?uxcK0y&$bRWsxkAsb(KScc
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z*jK3^?RSx$EjjQ~UmAalu(us}sY8vwOW1o3ywtVEFB7(`@X1=$_!S3M>Q!TPzQI9y
zPGj%Wv%uk7>Qm!gSgC!Dec<pby`Zr!ztT$@`*6T7|JT4izTNs6|JSG#?0=1H&Q$y}
nEaUze|8E}bU9vaRF%jK}=||wVwqL))yP5w+mE!-(*O2}T!8-Aw

literal 0
HcmV?d00001

diff --git a/llvm/test/tools/llvm-cov/gcov-fake-4.2.c b/llvm/test/tools/llvm-cov/gcov-fake-4.2.c
new file mode 100644
index 000000000000..7e8eb2f2a5ff
--- /dev/null
+++ b/llvm/test/tools/llvm-cov/gcov-fake-4.2.c
@@ -0,0 +1,39 @@
+/// Test that llvm-cov supports a fake gcov 4.2 format used before clang 11.
+
+// RUN: rm -rf %t && mkdir %t && cd %t
+// RUN: llvm-cov gcov test. --gcno=%S/Inputs/gcov-fake-4.2.gcno --gcda=%S/Inputs/gcov-fake-4.2.gcda | FileCheck %s
+// RUN: FileCheck %s --check-prefix=C < test.cpp.gcov
+// RUN: FileCheck %s --check-prefix=H < test.h.gcov
+
+// CHECK:       File 'test.cpp'
+// CHECK-NEXT:  Lines executed:84.21% of 38
+// CHECK-NEXT:  Creating 'test.cpp.gcov'
+// CHECK-EMPTY:
+// CHECK-NEXT:  File './test.h'
+// CHECK-NEXT:  Lines executed:100.00% of 1
+// CHECK-NEXT:  Creating 'test.h.gcov'
+// CHECK-EMPTY:
+
+//      C:        -:    0:Source:test.cpp
+// C-NEXT:        -:    0:Graph:{{.*}}gcov-fake-4.2.gcno
+// C-NEXT:        -:    0:Data:{{.*}}gcov-fake-4.2.gcda
+/// `Runs` is stored in GCOV_TAG_OBJECT_SUMMARY with a length of 9.
+// C-NEXT:        -:    0:Runs:2
+// C-NEXT:        -:    0:Programs:1
+// C-NEXT:        -:    1:
+// C-NEXT:        -:    2:
+// C-NEXT:        -:    3:
+// C-NEXT:        -:    4:
+// C-NEXT:        -:    5:
+// C-NEXT:        -:    6:
+// C-NEXT:        -:    7:
+// C-NEXT:        -:    8:
+// C-NEXT:        -:    9:
+// C-NEXT:8589934592:   10:
+
+//      H:        -:    0:Source:./test.h
+// H-NEXT:        -:    0:Graph:{{.*}}gcov-fake-4.2.gcno
+// H-NEXT:        -:    0:Data:{{.*}}gcov-fake-4.2.gcda
+// H-NEXT:        -:    0:Runs:2
+// H-NEXT:        -:    0:Programs:1
+// H-NEXT:        4:    1: