[PATCH] D77437: [lld][WebAssembly] Handle 4gb max memories

[Thomas Lively via Phabricator via llvm-commits]

tlively created this revision.
tlively added a reviewer: sbc100.
Herald added subscribers: llvm-commits, sunfish, aheejin, jgravelle-google, dschuff.
Herald added a project: LLVM.

A previous change (53211a) had updated the argument parsing to handle
large max memories, but 4294967296 would still wrap to zero after the
options were parsed. This change updates the configuration to use a
64-bit integer to store the max memory to avoid that overflow.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D77437

Files:
  lld/test/wasm/large-memory.test
  lld/wasm/Config.h
  lld/wasm/Writer.cpp


Index: lld/wasm/Writer.cpp
===================================================================
--- lld/wasm/Writer.cpp
+++ lld/wasm/Writer.cpp
@@ -201,7 +201,7 @@
 // rather than overwriting global data, but also increases code size since all
 // static data loads and stores requires larger offsets.
 void Writer::layoutMemory() {
-  uint32_t memoryPtr = 0;
+  uint64_t memoryPtr = 0;
 
   auto placeStack = [&]() {
     if (config->relocatable || config->isPic)
@@ -227,7 +227,7 @@
   if (WasmSym::globalBase)
     WasmSym::globalBase->setVirtualAddress(memoryPtr);
 
-  uint32_t dataStart = memoryPtr;
+  uint64_t dataStart = memoryPtr;
 
   // Arbitrarily set __dso_handle handle to point to the start of the data
   // segments.
Index: lld/wasm/Config.h
===================================================================
--- lld/wasm/Config.h
+++ lld/wasm/Config.h
@@ -46,9 +46,9 @@
   bool stripDebug;
   bool stackFirst;
   bool trace;
-  uint32_t globalBase;
-  uint32_t initialMemory;
-  uint32_t maxMemory;
+  uint64_t globalBase;
+  uint64_t initialMemory;
+  uint64_t maxMemory;
   uint32_t zStackSize;
   unsigned ltoPartitions;
   unsigned ltoo;
Index: lld/test/wasm/large-memory.test
===================================================================
--- lld/test/wasm/large-memory.test
+++ lld/test/wasm/large-memory.test
@@ -2,4 +2,16 @@
 
 ; Verify we can parse large integers such as when we ask for 2G of total
 ; memory.
-RUN: wasm-ld %t.o -o %t.wasm --max-memory=2147483648
+RUN: wasm-ld %t.o -o %t1.wasm --max-memory=2147483648
+RUN: obj2yaml %t1.wasm | FileCheck %s --check-prefixes=CHECK,CHECK-2G
+
+; And also 4G of total memory
+RUN: wasm-ld %t.o -o %t2.wasm --max-memory=4294967296
+RUN: obj2yaml %t2.wasm | FileCheck %s --check-prefixes=CHECK,CHECK-4G
+
+CHECK:      - Type:            MEMORY
+CHECK-NEXT:   Memories:
+CHECK-NEXT:     - Flags:           [ HAS_MAX ]
+CHECK-NEXT:       Initial:         0x00000002
+CHECK-2G-NEXT:    Maximum:         0x00008000
+CHECK-4G-NEXT:    Maximum:         0x00010000


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