https://github.com/llvmbot updated
https://github.com/llvm/llvm-project/pull/129762
>From 03fdc56648c828794749d6d9e8a7a0d28e26a4c6 Mon Sep 17 00:00:00 2001
From: Nick Fitzgerald
Date: Tue, 4 Mar 2025 09:39:30 -0800
Subject: [PATCH] [lld][WebAssembly] Support for the custom-page-sizes
WebAssembly proposal (#128942)
This commit adds support for WebAssembly's custom-page-sizes proposal to
`wasm-ld`. An overview of the proposal can be found
[here](https://github.com/WebAssembly/custom-page-sizes/blob/main/proposals/custom-page-sizes/Overview.md).
In a sentence, it allows customizing a Wasm memory's page size, enabling
Wasm to target environments with less than 64KiB of memory (the default
Wasm page size) available for Wasm memories.
This commit contains the following:
* Adds a `--page-size=N` CLI flag to `wasm-ld` for configuring the
linked Wasm binary's linear memory's page size.
* When the page size is configured to a non-default value, then the
final Wasm binary will use the encodings defined in the
custom-page-sizes proposal to declare the linear memory's page size.
* Defines a `__wasm_first_page_end` symbol, whose address points to the
first page in the Wasm linear memory, a.k.a. is the Wasm memory's page
size. This allows writing code that is compatible with any page size,
and doesn't require re-compiling its object code. At the same time,
because it just lowers to a constant rather than a memory access or
something, it enables link-time optimization.
* Adds tests for these new features.
r? @sbc100
cc @sunfishcode
(cherry picked from commit 6018930ef1fa62315c3e02b8b8b775056bd5224d)
---
lld/test/wasm/initial-heap.test | 2 +-
lld/test/wasm/mutable-global-exports.s| 4 +-
lld/test/wasm/page-size.s | 43 +++
lld/test/wasm/shared-memory.yaml | 2 +-
lld/wasm/Config.h | 1 +
lld/wasm/Driver.cpp | 10 -
lld/wasm/Options.td | 3 ++
lld/wasm/SymbolTable.cpp | 4 +-
lld/wasm/Symbols.cpp | 1 +
lld/wasm/Symbols.h| 4 ++
lld/wasm/SyntheticSections.cpp| 4 ++
lld/wasm/Writer.cpp | 23 +-
lld/wasm/WriterUtils.cpp | 4 ++
llvm/include/llvm/BinaryFormat/Wasm.h | 12 --
llvm/include/llvm/BinaryFormat/WasmTraits.h | 4 +-
llvm/include/llvm/MC/MCSymbolWasm.h | 2 +-
llvm/include/llvm/ObjectYAML/WasmYAML.h | 1 +
llvm/lib/MC/WasmObjectWriter.cpp | 3 +-
llvm/lib/Object/WasmObjectFile.cpp| 6 +++
llvm/lib/ObjectYAML/WasmYAML.cpp | 3 ++
.../AsmParser/WebAssemblyAsmParser.cpp| 2 +-
.../WebAssembly/WebAssemblyUtilities.cpp | 2 +-
llvm/tools/obj2yaml/wasm2yaml.cpp | 1 +
23 files changed, 116 insertions(+), 25 deletions(-)
create mode 100644 lld/test/wasm/page-size.s
diff --git a/lld/test/wasm/initial-heap.test b/lld/test/wasm/initial-heap.test
index 3e8bbd36535d3..5129ff4d09d7b 100644
--- a/lld/test/wasm/initial-heap.test
+++ b/lld/test/wasm/initial-heap.test
@@ -20,7 +20,7 @@ RUN: not wasm-ld %t.o -o %t5.wasm --stack-first -z
stack-size=131072 --initial-h
RUN: not wasm-ld %t.o -o %t6.wasm --stack-first -z stack-size=65536
--initial-heap=131072 --initial-memory=131072 2>&1 | FileCheck %s
--check-prefix INITIAL-MEMORY-TOO-SMALL
RUN: not wasm-ld %t.o -o %t7.wasm --stack-first -z stack-size=65536
--initial-heap=131072 --max-memory=131072 2>&1 | FileCheck %s --check-prefix
MAX-MEMORY-TOO-SMALL
-NOT-PAGE-MULTIPLE: initial heap must be 65536-byte aligned
+NOT-PAGE-MULTIPLE: initial heap must be aligned to the page size (65536 bytes)
TOO-LARGE-BY-ITSELF: initial heap too large, cannot be greater than 4294901760
TOO-LARGE-WITH-STACK: initial heap too large, cannot be greater than 4294836224
INITIAL-MEMORY-TOO-SMALL: initial memory too small, 196608 bytes needed
diff --git a/lld/test/wasm/mutable-global-exports.s
b/lld/test/wasm/mutable-global-exports.s
index 135559d5249bc..59308496ab4cc 100644
--- a/lld/test/wasm/mutable-global-exports.s
+++ b/lld/test/wasm/mutable-global-exports.s
@@ -101,6 +101,9 @@ _start:
# CHECK-ALL-NEXT: - Name:__table_base
# CHECK-ALL-NEXT:Kind:GLOBAL
# CHECK-ALL-NEXT:Index: 10
+# CHECK-ALL-NEXT: - Name:__wasm_first_page_end
+# CHECK-ALL-NEXT:Kind:GLOBAL
+# CHECK-ALL-NEXT:Index: 11
# CHECK-ALL-NEXT: - Type:CODE
# CHECK-ALL: Name:target_features
@@ -110,4 +113,3 @@ _start:
# CHECK-ALL-NEXT: - Prefix: USED
# CHECK-ALL-NEXT:Name:mutable-globals
# CHECK-ALL-NEXT: ...
-
diff --git a/lld/test/wasm/page-size.s b/lld/test/wasm/page-size.s
new file mode 100644
index 0..9f5826109d27c
--- /
