Mercurial > hg > orthanc
comparison OrthancFramework/Resources/WebAssembly.txt @ 4063:e00f3d089991 framework
shared library of orthanc framework
| author | Sebastien Jodogne <s.jodogne@gmail.com> |
|---|---|
| date | Thu, 11 Jun 2020 16:40:34 +0200 |
| parents | |
| children | e62bd014ae5c |
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| 4062:0953b3dc3261 | 4063:e00f3d089991 |
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| 1 | |
| 2 ====================================== | |
| 3 == Notes about WebAssembly =========== | |
| 4 ====================================== | |
| 5 | |
| 6 | |
| 7 | |
| 8 Trap mode | |
| 9 ========= | |
| 10 | |
| 11 The BINARYEN_TRAP_MODE specifies what to do when divisions per zero | |
| 12 (and similar conditions like integer overflows) are encountered. This | |
| 13 can be set through the option "EMSCRIPTEN_TRAP_MODE" in Orthanc. | |
| 14 | |
| 15 | |
| 16 | |
| 17 Previous versions (<= 1.7.1) | |
| 18 ---------------------------- | |
| 19 | |
| 20 The "clamp" mode avoids throwing errors, as they cannot be properly | |
| 21 catched by "try {} catch (...)" constructions. HOWEVER, the "upstream" | |
| 22 backend of Emscripten (which is now the default) doesn't support this | |
| 23 option. | |
| 24 | |
| 25 In Orthanc <= 1.7.1, the "clamp" mode was used by default. As a | |
| 26 consequence, there was an old flag "EMSCRIPTEN_SET_LLVM_WASM_BACKEND" | |
| 27 to setting BINARYEN_TRAP_MODE. | |
| 28 | |
| 29 Here is the definition of the parameter that was in | |
| 30 "OrthancFrameworkParameters.cmake": | |
| 31 | |
| 32 >>>>> | |
| 33 set(EMSCRIPTEN_SET_LLVM_WASM_BACKEND OFF CACHE BOOL "Sets the compiler flags required to use the LLVM Web Assembly backend in emscripten") | |
| 34 <<<<< | |
| 35 | |
| 36 Setting this option to "ON" fixes error: "shared:ERROR: | |
| 37 BINARYEN_TRAP_MODE is not supported by the LLVM wasm backend" if using | |
| 38 the "upstream" backend of Emscripten. Here is the corresponding | |
| 39 implementation that was in "Compiler.cmake": | |
| 40 | |
| 41 >>>>> | |
| 42 if (NOT EMSCRIPTEN_SET_LLVM_WASM_BACKEND) | |
| 43 set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -s BINARYEN_TRAP_MODE='\"clamp\"'") | |
| 44 endif() | |
| 45 <<<<< | |
| 46 | |
| 47 | |
| 48 | |
| 49 | |
| 50 Linker flags | |
| 51 ============ | |
| 52 | |
| 53 Since Orthanc 1.7.2, "Compiler.cmake" doesn't set any linking option | |
| 54 for Emscripten. In Orthanc <= 1.7.1, the following was done: | |
| 55 | |
| 56 >>>>> | |
| 57 set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -s EXTRA_EXPORTED_RUNTIME_METHODS='[\"ccall\", \"cwrap\"]'") | |
| 58 <<<<< |