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lld-link: Store comdat selection in SectionChunk, reject more invalid associated comdats

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I need the comdat selection for PR40094. To keep the patch for that smaller,
I'm adding it here, and as a first application I'm using it to reject
associative comdats referring to earlier associative comdats. Depends on
D56929; together with that all associative comdats referring to other
associative comdats are now rejected.

Differential Revision: https://reviews.llvm.org/D56931

llvm-svn: 352254
This commit is contained in:
Nico Weber 2019-01-26 00:14:52 +00:00
parent e9cac31dac
commit 6bb3a1aa75
3 changed files with 32 additions and 12 deletions
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3
lld/COFF/Chunks.h
View File

@ -223,6 +223,9 @@ public:
// The COMDAT leader symbol if this is a COMDAT chunk.
DefinedRegular *Sym = nullptr;
// The COMDAT selection if this is a COMDAT chunk.
llvm::COFF::COMDATType Selection;
ArrayRef<coff_relocation> Relocs;
// Used by the garbage collector.

21
lld/COFF/InputFiles.cpp
View File

@ -226,10 +226,7 @@ void ObjFile::readAssociativeDefinition(COFFSymbolRef Sym,
uint32_t ParentIndex) {
SectionChunk *Parent = SparseChunks[ParentIndex];
if (Parent == PendingComdat) {
// This can happen if an associative comdat refers to another associative
// comdat that appears after it (invalid per COFF spec) or to a section
// without any symbols.
auto Diag = [&]() {
StringRef Name, ParentName;
COFFObj->getSymbolName(Sym, Name);
@ -238,6 +235,13 @@ void ObjFile::readAssociativeDefinition(COFFSymbolRef Sym,
COFFObj->getSectionName(ParentSec, ParentName);
error(toString(this) + ": associative comdat " + Name +
" has invalid reference to section " + ParentName);
};
if (Parent == PendingComdat) {
// This can happen if an associative comdat refers to another associative
// comdat that appears after it (invalid per COFF spec) or to a section
// without any symbols.
Diag();
return;
}
@ -245,7 +249,14 @@ void ObjFile::readAssociativeDefinition(COFFSymbolRef Sym,
// the section; otherwise mark it as discarded.
int32_t SectionNumber = Sym.getSectionNumber();
if (Parent) {
SparseChunks[SectionNumber] = readSection(SectionNumber, Def, "");
if (Parent->Selection == IMAGE_COMDAT_SELECT_ASSOCIATIVE) {
Diag();
return;
}
SectionChunk *C = readSection(SectionNumber, Def, "");
C->Selection = IMAGE_COMDAT_SELECT_ASSOCIATIVE;
SparseChunks[SectionNumber] = C;
if (SparseChunks[SectionNumber])
Parent->addAssociative(SparseChunks[SectionNumber]);
} else {

20
lld/test/COFF/associative-comdat-order.test
View File

@ -1,10 +1,16 @@
# RUN: yaml2obj < %s > %t.obj
# RUN: not lld-link /include:symbol /dll /noentry /nodefaultlib %t.obj /out:%t.exe 2>&1 | FileCheck %s
# Tests that an associative comdat being associated with another
# associated comdat later in the file produces an error.
# CHECK: lld-link: error: {{.*}}: associative comdat .text$ac1 has invalid reference to section .text$ac2
# CHECK-NOT: lld-link: error:
# RUN: sed -e s/ASSOC1/2/ -e s/ASSOC2/3/ %s | yaml2obj > %t.obj
# RUN: not lld-link /include:symbol /dll /noentry /nodefaultlib %t.obj /out:%t.exe 2>&1 | FileCheck --check-prefix=FORWARD %s
# FORWARD: lld-link: error: {{.*}}: associative comdat .text$ac1 has invalid reference to section .text$ac2
# FORWARD-NOT: lld-link: error:
# Tests that an associative comdat being associated with another
# associated comdat earlier in the file produces an error.
# RUN: sed -e s/ASSOC1/3/ -e s/ASSOC2/1/ %s | yaml2obj > %t.obj
# RUN: not lld-link /include:symbol /dll /noentry /nodefaultlib %t.obj /out:%t.exe 2>&1 | FileCheck --check-prefix=BACKWARD %s
# BACKWARD: lld-link: error: {{.*}}: associative comdat .text$ac2 has invalid reference to section .text$ac1
# BACKWARD-NOT: lld-link: error:
--- !COFF
header:
@ -35,7 +41,7 @@ symbols:
NumberOfRelocations: 0
NumberOfLinenumbers: 0
CheckSum: 3099354981
Number: 2
Number: ASSOC1
Selection: IMAGE_COMDAT_SELECT_ASSOCIATIVE
- Name: '.text$ac2'
Value: 0
@ -48,7 +54,7 @@ symbols:
NumberOfRelocations: 0
NumberOfLinenumbers: 0
CheckSum: 3099354981
Number: 3
Number: ASSOC2
Selection: IMAGE_COMDAT_SELECT_ASSOCIATIVE
- Name: '.text$nm'
Value: 0