Revert "[WebAssembly] MC layer writes table symbols to object files"

This reverts commit d806618636f8a82bfc3f620e1fad83af4d2a2575.
Review: https://reviews.llvm.org/D92215

We had issues where older versions of wasm-ld were crashing on object
files containing a table symbol.  We decided that the best strategy
going forward is to only generate these symbol if refernece types is
enabled.  Without reference types enabled we should never geneate a
table symbol or a TABLE_NUMBER relocation.

This revert is in addition to the one already reverted in
https://reviews.llvm.org/D95005.

The plan is to re-land these in updated form after the llvm 12 branch.

Differential Revision: https://reviews.llvm.org/D95420

diff --git a/llvm/lib/MC/WasmObjectWriter.cpp b/llvm/lib/MC/WasmObjectWriter.cpp
index 6cdfe1c..930413e 100644 (file)
--- a/llvm/lib/MC/WasmObjectWriter.cpp
+++ b/llvm/lib/MC/WasmObjectWriter.cpp
@@ -519,13 +519,6 @@ void WasmObjectWriter::recordRelocation(MCAssembler &Asm,
       Sym->setUndefined();
     }
     Sym->setUsedInReloc();
-    // Any time we have a TABLE_INDEX relocation against a function symbol, we
-    // need to ensure that table itself is part of the final output too.  In the
-    // future we may want to define a new kind of reloc against both the
-    // function and the table, so that the linker can see that the function
-    // symbol keeps the table alive, but for now manually mark the table as
-    // live.
-    Sym->setNoStrip();
     Asm.registerSymbol(*Sym);
   }
 
@@ -1678,6 +1671,10 @@ uint64_t WasmObjectWriter::writeOneObject(MCAssembler &Asm,
       WS.setIndex(InvalidIndex);
       continue;
     }
+    if (WS.isTable() && WS.getName() == "__indirect_function_table") {
+      // For the moment, don't emit table symbols -- wasm-ld can't handle them.
+      continue;
+    }
     LLVM_DEBUG(dbgs() << "adding to symtab: " << WS << "\n");
 
     uint32_t Flags = 0;

diff --git a/llvm/test/MC/WebAssembly/debug-info.ll b/llvm/test/MC/WebAssembly/debug-info.ll
index 88d19d9..167d912 100644 (file)
--- a/llvm/test/MC/WebAssembly/debug-info.ll
+++ b/llvm/test/MC/WebAssembly/debug-info.ll
@@ -89,44 +89,44 @@
 ; CHECK-NEXT:  }
 ; CHECK-NEXT:  Section {
 ; CHECK-NEXT:    Type: CUSTOM (0x0)
-; CHECK-NEXT:    Size: 95
+; CHECK-NEXT:    Size: 91
 ; CHECK-NEXT:    Offset: 731
 ; CHECK-NEXT:    Name: linking
 ; CHECK-NEXT:  }
 ; CHECK-NEXT:  Section {
 ; CHECK-NEXT:    Type: CUSTOM (0x0)
 ; CHECK-NEXT:    Size: 9
-; CHECK-NEXT:    Offset: 840
+; CHECK-NEXT:    Offset: 836
 ; CHECK-NEXT:    Name: reloc.DATA
 ; CHECK-NEXT:  }
 ; CHECK-NEXT:  Section {
 ; CHECK-NEXT:    Type: CUSTOM (0x0)
 ; CHECK-NEXT:    Size: 61
-; CHECK-NEXT:    Offset: 866
+; CHECK-NEXT:    Offset: 862
 ; CHECK-NEXT:    Name: reloc..debug_info
 ; CHECK-NEXT:  }
 ; CHECK-NEXT:  Section {
 ; CHECK-NEXT:    Type: CUSTOM (0x0)
 ; CHECK-NEXT:    Size: 6
-; CHECK-NEXT:    Offset: 951
+; CHECK-NEXT:    Offset: 947
 ; CHECK-NEXT:    Name: reloc..debug_pubnames
 ; CHECK-NEXT:  }
 ; CHECK-NEXT:  Section {
 ; CHECK-NEXT:    Type: CUSTOM (0x0)
 ; CHECK-NEXT:    Size: 6
-; CHECK-NEXT:    Offset: 985
+; CHECK-NEXT:    Offset: 981
 ; CHECK-NEXT:    Name: reloc..debug_pubtypes
 ; CHECK-NEXT:  }
 ; CHECK-NEXT:  Section {
 ; CHECK-NEXT:    Type: CUSTOM (0x0)
 ; CHECK-NEXT:    Size: 6
-; CHECK-NEXT:    Offset: 1019
+; CHECK-NEXT:    Offset: 1015
 ; CHECK-NEXT:    Name: reloc..debug_line
 ; CHECK-NEXT:  }
 ; CHECK-NEXT:  Section {
 ; CHECK-NEXT:    Type: CUSTOM (0x0)
 ; CHECK-NEXT:    Size: 77
-; CHECK-NEXT:    Offset: 1049
+; CHECK-NEXT:    Offset: 1045
 ; CHECK-NEXT:    Name: producers
 ; CHECK-NEXT:  }
 ; CHECK-NEXT:]
@@ -238,16 +238,6 @@
 ; CHECK-NEXT:    ]
 ; CHECK-NEXT:    ElementIndex: 0xC
 ; CHECK-NEXT:  }
-; CHECK-NEXT:  Symbol {
-; CHECK-NEXT:    Name: __indirect_function_table
-; CHECK-NEXT:    Type: TABLE (0x5)
-; CHECK-NEXT:    Flags [ (0x90)
-; CHECK-NEXT:      NO_STRIP (0x80)
-; CHECK-NEXT:      UNDEFINED (0x10)
-; CHECK-NEXT:    ]
-; CHECK-NEXT:    ImportModule: env
-; CHECK-NEXT:    ElementIndex: 0x0
-; CHECK-NEXT:  }
 ; CHECK-NEXT:]
 
 ; generated from the following C code using: clang --target=wasm32 -g -O0 -S -emit-llvm test.c

diff --git a/llvm/test/MC/WebAssembly/debug-info64.ll b/llvm/test/MC/WebAssembly/debug-info64.ll
index 1755f2b..acba8aa 100644 (file)
--- a/llvm/test/MC/WebAssembly/debug-info64.ll
+++ b/llvm/test/MC/WebAssembly/debug-info64.ll
@@ -89,44 +89,44 @@
 ; CHECK-NEXT:   }
 ; CHECK-NEXT:   Section {
 ; CHECK-NEXT:     Type: CUSTOM (0x0)
-; CHECK-NEXT:     Size: 95
+; CHECK-NEXT:     Size: 91
 ; CHECK-NEXT:     Offset: 759
 ; CHECK-NEXT:     Name: linking
 ; CHECK-NEXT:   }
 ; CHECK-NEXT:   Section {
 ; CHECK-NEXT:     Type: CUSTOM (0x0)
 ; CHECK-NEXT:     Size: 9
-; CHECK-NEXT:     Offset: 868
+; CHECK-NEXT:     Offset: 864
 ; CHECK-NEXT:     Name: reloc.DATA
 ; CHECK-NEXT:   }
 ; CHECK-NEXT:   Section {
 ; CHECK-NEXT:     Type: CUSTOM (0x0)
 ; CHECK-NEXT:     Size: 61
-; CHECK-NEXT:     Offset: 894
+; CHECK-NEXT:     Offset: 890
 ; CHECK-NEXT:     Name: reloc..debug_info
 ; CHECK-NEXT:   }
 ; CHECK-NEXT:   Section {
 ; CHECK-NEXT:     Type: CUSTOM (0x0)
 ; CHECK-NEXT:     Size: 6
-; CHECK-NEXT:     Offset: 979
+; CHECK-NEXT:     Offset: 975
 ; CHECK-NEXT:     Name: reloc..debug_pubnames
 ; CHECK-NEXT:   }
 ; CHECK-NEXT:   Section {
 ; CHECK-NEXT:     Type: CUSTOM (0x0)
 ; CHECK-NEXT:     Size: 6
-; CHECK-NEXT:     Offset: 1013
+; CHECK-NEXT:     Offset: 1009
 ; CHECK-NEXT:     Name: reloc..debug_pubtypes
 ; CHECK-NEXT:   }
 ; CHECK-NEXT:   Section {
 ; CHECK-NEXT:     Type: CUSTOM (0x0)
 ; CHECK-NEXT:     Size: 6
-; CHECK-NEXT:     Offset: 1047
+; CHECK-NEXT:     Offset: 1043
 ; CHECK-NEXT:     Name: reloc..debug_line
 ; CHECK-NEXT:   }
 ; CHECK-NEXT:   Section {
 ; CHECK-NEXT:     Type: CUSTOM (0x0)
 ; CHECK-NEXT:     Size: 77
-; CHECK-NEXT:     Offset: 1077
+; CHECK-NEXT:     Offset: 1073
 ; CHECK-NEXT:     Name: producers
 ; CHECK-NEXT:   }
 ; CHECK-NEXT: ]
@@ -238,16 +238,6 @@
 ; CHECK-NEXT:     ]
 ; CHECK-NEXT:     ElementIndex: 0xC
 ; CHECK-NEXT:   }
-; CHECK-NEXT:   Symbol {
-; CHECK-NEXT:     Name: __indirect_function_table
-; CHECK-NEXT:     Type: TABLE (0x5)
-; CHECK-NEXT:     Flags [ (0x90)
-; CHECK-NEXT:       NO_STRIP (0x80)
-; CHECK-NEXT:       UNDEFINED (0x10)
-; CHECK-NEXT:     ]
-; CHECK-NEXT:     ImportModule: env
-; CHECK-NEXT:     ElementIndex: 0x0
-; CHECK-NEXT:   }
 ; CHECK-NEXT: ]
 
 ; generated from the following C code using: clang --target=wasm64 -g -O0 -S -emit-llvm test.c

diff --git a/llvm/test/MC/WebAssembly/function-alias.ll b/llvm/test/MC/WebAssembly/function-alias.ll
index 8cd4252..ec57108 100644 (file)
--- a/llvm/test/MC/WebAssembly/function-alias.ll
+++ b/llvm/test/MC/WebAssembly/function-alias.ll
@@ -41,14 +41,4 @@ define i8* @func() {
 ; CHECK-NEXT:     ]
 ; CHECK-NEXT:     ElementIndex: 0x0
 ; CHECK-NEXT:   }
-; CHECK-NEXT:   Symbol {
-; CHECK-NEXT:     Name: __indirect_function_table
-; CHECK-NEXT:     Type: TABLE (0x5)
-; CHECK-NEXT:     Flags [ (0x90)
-; CHECK-NEXT:       NO_STRIP (0x80)
-; CHECK-NEXT:       UNDEFINED (0x10)
-; CHECK-NEXT:     ]
-; CHECK-NEXT:     ImportModule: env
-; CHECK-NEXT:     ElementIndex: 0x0
-; CHECK-NEXT:   }
 ; CHECK-NEXT: ]

diff --git a/llvm/test/MC/WebAssembly/global-ctor-dtor.ll b/llvm/test/MC/WebAssembly/global-ctor-dtor.ll
index 0de7cfc..5f56cb6 100644 (file)
--- a/llvm/test/MC/WebAssembly/global-ctor-dtor.ll
+++ b/llvm/test/MC/WebAssembly/global-ctor-dtor.ll
@@ -170,11 +170,6 @@ declare void @func3()
 ; CHECK-NEXT:         Name:            func0
 ; CHECK-NEXT:         Flags:           [ UNDEFINED ]
 ; CHECK-NEXT:         Function:        4
-; CHECK-NEXT:       - Index:           11
-; CHECK-NEXT:         Kind:            TABLE
-; CHECK-NEXT:         Name:            __indirect_function_table
-; CHECK-NEXT:         Flags:           [ UNDEFINED, NO_STRIP ]
-; CHECK-NEXT:         Table:           0
 ; CHECK-NEXT:     SegmentInfo:
 ; CHECK-NEXT:       - Index:           0
 ; CHECK-NEXT:         Name:            .data.global1

diff --git a/llvm/test/MC/WebAssembly/reloc-pic.s b/llvm/test/MC/WebAssembly/reloc-pic.s
index 1842e92..b7995eb 100644 (file)
--- a/llvm/test/MC/WebAssembly/reloc-pic.s
+++ b/llvm/test/MC/WebAssembly/reloc-pic.s
@@ -190,11 +190,6 @@ hidden_func:
 # CHECK-NEXT:         Name:            hidden_func
 # CHECK-NEXT:         Flags:           [ BINDING_LOCAL ]
 # CHECK-NEXT:         Function:        5
-# CHECK-NEXT:       - Index:           10
-# CHECK-NEXT:         Kind:            TABLE
-# CHECK-NEXT:         Name:            __indirect_function_table
-# CHECK-NEXT:         Flags:           [ UNDEFINED, NO_STRIP ]
-# CHECK-NEXT:         Table:           0
 # CHECK-NEXT:     SegmentInfo:
 # CHECK-NEXT:       - Index:           0
 # CHECK-NEXT:         Name:            .rodata.hidden_data

diff --git a/llvm/test/MC/WebAssembly/type-index.s b/llvm/test/MC/WebAssembly/type-index.s
index dfaaad5..298e5e2 100644 (file)
--- a/llvm/test/MC/WebAssembly/type-index.s
+++ b/llvm/test/MC/WebAssembly/type-index.s
@@ -66,9 +66,4 @@ test0:
 # BIN-NEXT:         Name:            test0
 # BIN-NEXT:         Flags:           [ BINDING_LOCAL ]
 # BIN-NEXT:         Function:        0
-# BIN-NEXT:       - Index:           1
-# BIN-NEXT:         Kind:            TABLE
-# BIN-NEXT:         Name:            __indirect_function_table
-# BIN-NEXT:         Flags:           [ UNDEFINED, NO_STRIP ]
-# BIN-NEXT:         Table:           0
 # BIN-NEXT: ...

diff --git a/llvm/test/MC/WebAssembly/weak-alias.s b/llvm/test/MC/WebAssembly/weak-alias.s
index 139a681..4590e00 100644 (file)
--- a/llvm/test/MC/WebAssembly/weak-alias.s
+++ b/llvm/test/MC/WebAssembly/weak-alias.s
@@ -227,11 +227,6 @@ alias_address:
 # CHECK-NEXT:         Flags:           [ BINDING_WEAK, VISIBILITY_HIDDEN, NO_STRIP ]
 # CHECK-NEXT:         Segment:         0
 # CHECK-NEXT:         Size:            4
-# CHECK-NEXT:       - Index:           10
-# CHECK-NEXT:         Kind:            TABLE
-# CHECK-NEXT:         Name:            __indirect_function_table
-# CHECK-NEXT:         Flags:           [ UNDEFINED, NO_STRIP ]
-# CHECK-NEXT:         Table:           0
 # CHECK-NEXT:     SegmentInfo:
 # CHECK-NEXT:       - Index:           0
 # CHECK-NEXT:         Name:            .data.bar