Fix a few issues with comdat handling on COFF.

* Section association cannot use just the section name as many
sections can have the same name. With this patch, the comdat symbol in
an assoc section is interpreted to mean a symbol in the associated
section and the mapping is discovered from it.

* Comdat symbols were not being set correctly. Instead we were getting
whatever was output first for that section.

A consequence is that associative sections now must use .section to
set the association. Using .linkonce would not work since it is not
possible to change a sections comdat symbol (it is used to decide if
we should create a new section or reuse an existing one).

This includes r210298, which was reverted because it was asserting
on an associated section having the same comdat as the associated
section.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210367 91177308-0d34-0410-b5e6-96231b3b80d8

6 files changed, 50 insertions, 69 deletions

diff --git a/test/MC/COFF/global_ctors_dtors.ll b/test/MC/COFF/global_ctors_dtors.ll
index 735c493683..ca17f24a68 100644
--- a/test/MC/COFF/global_ctors_dtors.ll
+++ b/test/MC/COFF/global_ctors_dtors.ll
@@ -51,14 +51,14 @@ define i32 @main() nounwind {
 
 ; WIN32: .section .CRT$XCU,"rd"
 ; WIN32: a_global_ctor
-; WIN32: .section .CRT$XCU,"rd",associative .bss,{{_?}}b
+; WIN32: .section .CRT$XCU,"rd",associative,{{_?}}b
 ; WIN32: b_global_ctor
 ; WIN32-NOT: c_global_ctor
 ; WIN32: .section .CRT$XTX,"rd"
 ; WIN32: a_global_dtor
 ; MINGW32: .section .ctors,"wd"
 ; MINGW32: a_global_ctor
-; MINGW32: .section .ctors,"wd",associative .bss,{{_?}}b
+; MINGW32: .section .ctors,"wd",associative,{{_?}}b
 ; MINGW32: b_global_ctor
 ; MINGW32-NOT: c_global_ctor
 ; MINGW32: .section .dtors,"wd"
diff --git a/test/MC/COFF/linkonce-invalid.s b/test/MC/COFF/linkonce-invalid.s
index 90ce4a7ad3..cc3a27c903 100644
--- a/test/MC/COFF/linkonce-invalid.s
+++ b/test/MC/COFF/linkonce-invalid.s
@@ -19,21 +19,9 @@
 // CHECK: error: unexpected token in directive
 .linkonce discard foo
 
-// CHECK: error: expected associated section name
+// CHECK: error: cannot make section associative with .linkonce
 .linkonce associative
 
-// CHECK: error: cannot associate unknown section 'unknown'
-.linkonce associative unknown
-
-// CHECK: error: cannot associate a section with itself
-.linkonce associative invalid
-
-// CHECK: error: associated section must be a COMDAT section
-.linkonce associative non_comdat
-
-// CHECK: error: associated section cannot be itself associative
-.linkonce associative assoc
-
 // CHECK: error: section 'multi' is already linkonce
 .section multi
 .linkonce discard
diff --git a/test/MC/COFF/linkonce.s b/test/MC/COFF/linkonce.s
index e7b7f475a3..b6e81ad4b6 100644
--- a/test/MC/COFF/linkonce.s
+++ b/test/MC/COFF/linkonce.s
@@ -24,7 +24,6 @@
 .long 1
 
 .section s6
-.linkonce associative s1
 .long 1
 
 .section s7
@@ -39,11 +38,6 @@
 .linkonce discard
 .long 1
 
-// Check that valid '.section' names can be associated.
-.section multi
-.linkonce associative .foo$bar
-.long 1
-
 
 // CHECK: Sections [
 // CHECK:   Section {
@@ -79,7 +73,6 @@
 // CHECK:   Section {
 // CHECK:     Name: s6
 // CHECK:     Characteristics [
-// CHECK:       IMAGE_SCN_LNK_COMDAT
 // CHECK:     ]
 // CHECK:   }
 // CHECK:   Section {
@@ -94,12 +87,6 @@
 // CHECK:       IMAGE_SCN_LNK_COMDAT
 // CHECK:     ]
 // CHECK:   }
-// CHECK:   Section {
-// CHECK:     Name: multi
-// CHECK:     Characteristics [
-// CHECK:       IMAGE_SCN_LNK_COMDAT
-// CHECK:     ]
-// CHECK:   }
 // CHECK: ]
 // CHECK: Symbols [
 // CHECK:   Symbol {
@@ -144,12 +131,6 @@
 // CHECK:   }
 // CHECK:   Symbol {
 // CHECK:     Name: s6
-// CHECK:     Section: s6 (6)
-// CHECK:     AuxSectionDef {
-// CHECK:       Number: 1
-// CHECK:       Selection: Associative (0x5)
-// CHECK:       AssocSection: s1
-// CHECK:     }
 // CHECK:   }
 // CHECK:   Symbol {
 // CHECK:     Name: s7
@@ -167,13 +148,3 @@
 // CHECK:       Selection: Newest (0x7)
 // CHECK:     }
 // CHECK:   }
-// CHECK:   Symbol {
-// CHECK:     Name: multi
-// CHECK:     Value: 0
-// CHECK:     Section: multi (10)
-// CHECK:     AuxSectionDef {
-// CHECK:       Number: 9
-// CHECK:       Selection: Associative (0x5)
-// CHECK:       AssocSection: .foo$bar
-// CHECK:     }
-// CHECK:   }
diff --git a/test/MC/COFF/section-comdat-conflict.s b/test/MC/COFF/section-comdat-conflict.s
new file mode 100644
index 0000000000..7ed452a5cd
--- /dev/null
+++ b/test/MC/COFF/section-comdat-conflict.s
@@ -0,0 +1,13 @@
+// RUN: not llvm-mc -triple i386-pc-win32 -filetype=obj < %s 2>&1 |  FileCheck %s
+
+// CHECK: conflicting sections for symbol
+
+        .section .xyz
+        .global bar
+bar:
+        .long 42
+
+        .section        .abcd,"xr",discard,bar
+        .global foo
+foo:
+        .long 42
diff --git a/test/MC/COFF/section-comdat-conflict2.s b/test/MC/COFF/section-comdat-conflict2.s
new file mode 100644
index 0000000000..e2dfc2d68b
--- /dev/null
+++ b/test/MC/COFF/section-comdat-conflict2.s
@@ -0,0 +1,6 @@
+// RUN: not llvm-mc -triple i386-pc-win32 -filetype=obj < %s 2>&1 |  FileCheck %s
+
+// CHECK: two sections have the same comdat
+
+        .section        .xyz,"xr",discard,bar
+        .section        .abcd,"xr",discard,bar
diff --git a/test/MC/COFF/section-comdat.s b/test/MC/COFF/section-comdat.s
index dd5be871b0..a0ea7d0928 100644
--- a/test/MC/COFF/section-comdat.s
+++ b/test/MC/COFF/section-comdat.s
@@ -1,8 +1,7 @@
 // RUN: llvm-mc -triple i386-pc-win32 -filetype=obj %s | llvm-readobj -s -t | FileCheck %s
 // RUN: llvm-mc -triple x86_64-pc-win32 -filetype=obj %s | llvm-readobj -s -t | FileCheck %s
 
-.section assocSec
-.linkonce
+.section assocSec, "dr", discard, "assocSym"
 .long 1
 
 .section secName, "dr", discard, "Symbol1"
@@ -25,7 +24,7 @@ Symbol3:
 Symbol4:
 .long 1
 
-.section SecName, "dr", associative assocSec, "Symbol5"
+.section SecName, "dr", associative, "assocSym"
 .globl Symbol5
 Symbol5:
 .long 1
@@ -107,6 +106,10 @@ Symbol7:
 // CHECK:     }
 // CHECK:   }
 // CHECK:   Symbol {
+// CHECK:     Name: assocSym
+// CHECK:     Section: assocSec
+// CHECK:   }
+// CHECK:   Symbol {
 // CHECK:     Name: secName
 // CHECK:     Section: secName (2)
 // CHECK:     AuxSectionDef {
@@ -114,6 +117,10 @@ Symbol7:
 // CHECK:     }
 // CHECK:   }
 // CHECK:   Symbol {
+// CHECK:     Name: Symbol1
+// CHECK:     Section: secName (2)
+// CHECK:   }
+// CHECK:   Symbol {
 // CHECK:     Name: secName
 // CHECK:     Section: secName (3)
 // CHECK:     AuxSectionDef {
@@ -121,6 +128,10 @@ Symbol7:
 // CHECK:     }
 // CHECK:   }
 // CHECK:   Symbol {
+// CHECK:     Name: Symbol2
+// CHECK:     Section: secName (3)
+// CHECK:   }
+// CHECK:   Symbol {
 // CHECK:     Name: SecName
 // CHECK:     Section: SecName (4)
 // CHECK:     AuxSectionDef {
@@ -128,6 +139,10 @@ Symbol7:
 // CHECK:     }
 // CHECK:   }
 // CHECK:   Symbol {
+// CHECK:     Name: Symbol3
+// CHECK:     Section: SecName (4)
+// CHECK:   }
+// CHECK:   Symbol {
 // CHECK:     Name: SecName
 // CHECK:     Section: SecName (5)
 // CHECK:     AuxSymbolCount: 1
@@ -136,6 +151,10 @@ Symbol7:
 // CHECK:     }
 // CHECK:   }
 // CHECK:   Symbol {
+// CHECK:     Name: Symbol4
+// CHECK:     Section: SecName (5)
+// CHECK:   }
+// CHECK:   Symbol {
 // CHECK:     Name: SecName
 // CHECK:     Section: SecName (6)
 // CHECK:     AuxSectionDef {
@@ -151,6 +170,10 @@ Symbol7:
 // CHECK:     }
 // CHECK:   }
 // CHECK:   Symbol {
+// CHECK:     Name: Symbol6
+// CHECK:     Section: SecName (7)
+// CHECK:   }
+// CHECK:   Symbol {
 // CHECK:     Name: SecName
 // CHECK:     Section: SecName (8)
 // CHECK:     AuxSectionDef {
@@ -158,31 +181,11 @@ Symbol7:
 // CHECK:     }
 // CHECK:   }
 // CHECK:   Symbol {
-// CHECK:     Name: Symbol1
-// CHECK:     Section: secName (2)
-// CHECK:   }
-// CHECK:   Symbol {
-// CHECK:     Name: Symbol2
-// CHECK:     Section: secName (3)
-// CHECK:   }
-// CHECK:   Symbol {
-// CHECK:     Name: Symbol3
-// CHECK:     Section: SecName (4)
-// CHECK:   }
-// CHECK:   Symbol {
-// CHECK:     Name: Symbol4
-// CHECK:     Section: SecName (5)
+// CHECK:     Name: Symbol7
+// CHECK:     Section: SecName (8)
 // CHECK:   }
 // CHECK:   Symbol {
 // CHECK:     Name: Symbol5
 // CHECK:     Section: SecName (6)
 // CHECK:   }
-// CHECK:   Symbol {
-// CHECK:     Name: Symbol6
-// CHECK:     Section: SecName (7)
-// CHECK:   }
-// CHECK:   Symbol {
-// CHECK:     Name: Symbol7
-// CHECK:     Section: SecName (8)
-// CHECK:   }
 // CHECK: ]