Switch to qvla where it makes sense in rhi

For all of these we know in advance that the vast majority of usages
will not exceed a certain number of elements. Also, none of these are
copied or moved ever.

Change-Id: I48aedf143e221dc178d661e23454d1e4fb7a271b
Reviewed-by: Andy Nichols <andy.nichols@qt.io>

8 files changed, 43 insertions, 39 deletions

diff --git a/src/gui/rhi/qrhi_p_p.h b/src/gui/rhi/qrhi_p_p.h
index 552e2695ce..b5cf660409 100644
--- a/src/gui/rhi/qrhi_p_p.h
+++ b/src/gui/rhi/qrhi_p_p.h
@@ -228,7 +228,7 @@ private:
     QBitArray resUpdPoolMap;
     QSet<QRhiResource *> resources;
     QSet<QRhiResource *> pendingDeleteResources;
-    QList<QRhi::CleanupCallback> cleanupCallbacks;
+    QVarLengthArray<QRhi::CleanupCallback, 4> cleanupCallbacks;
 
     friend class QRhi;
     friend class QRhiResourceUpdateBatchPrivate;
diff --git a/src/gui/rhi/qrhid3d11.cpp b/src/gui/rhi/qrhid3d11.cpp
index 6157381acb..e5b03e1d0e 100644
--- a/src/gui/rhi/qrhid3d11.cpp
+++ b/src/gui/rhi/qrhid3d11.cpp
@@ -1641,7 +1641,7 @@ void QRhiD3D11::finishActiveReadbacks()
         if (readback.result->completed)
             completedCallbacks.append(readback.result->completed);
 
-        activeTextureReadbacks.removeAt(i);
+        activeTextureReadbacks.removeLast();
     }
 
     for (int i = activeBufferReadbacks.count() - 1; i >= 0; --i) {
@@ -1663,7 +1663,7 @@ void QRhiD3D11::finishActiveReadbacks()
         if (readback.result->completed)
             completedCallbacks.append(readback.result->completed);
 
-        activeBufferReadbacks.removeAt(i);
+        activeBufferReadbacks.removeLast();
     }
 
     for (auto f : completedCallbacks)
diff --git a/src/gui/rhi/qrhid3d11_p_p.h b/src/gui/rhi/qrhid3d11_p_p.h
index baecc2fe21..c6890ca353 100644
--- a/src/gui/rhi/qrhid3d11_p_p.h
+++ b/src/gui/rhi/qrhid3d11_p_p.h
@@ -469,17 +469,17 @@ struct QD3D11CommandBuffer : public QRhiCommandBuffer
     ID3D11Buffer *currentVertexBuffers[D3D11_IA_VERTEX_INPUT_RESOURCE_SLOT_COUNT];
     quint32 currentVertexOffsets[D3D11_IA_VERTEX_INPUT_RESOURCE_SLOT_COUNT];
 
-    QList<QByteArray> dataRetainPool;
-    QList<QImage> imageRetainPool;
+    QVarLengthArray<QByteArray, 4> dataRetainPool;
+    QVarLengthArray<QImage, 4> imageRetainPool;
 
     // relies heavily on implicit sharing (no copies of the actual data will be made)
     const uchar *retainData(const QByteArray &data) {
         dataRetainPool.append(data);
-        return reinterpret_cast<const uchar *>(dataRetainPool.constLast().constData());
+        return reinterpret_cast<const uchar *>(dataRetainPool.last().constData());
     }
     const uchar *retainImage(const QImage &image) {
         imageRetainPool.append(image);
-        return imageRetainPool.constLast().constBits();
+        return imageRetainPool.last().constBits();
     }
     void resetCommands() {
         commands.clear();
@@ -707,13 +707,13 @@ public:
         QSize pixelSize;
         QRhiTexture::Format format;
     };
-    QList<TextureReadback> activeTextureReadbacks;
+    QVarLengthArray<TextureReadback, 2> activeTextureReadbacks;
     struct BufferReadback {
         QRhiBufferReadbackResult *result;
         quint32 byteSize;
         ID3D11Buffer *stagingBuf;
     };
-    QList<BufferReadback> activeBufferReadbacks;
+    QVarLengthArray<BufferReadback, 2> activeBufferReadbacks;
 
     struct Shader {
         Shader() = default;
diff --git a/src/gui/rhi/qrhigles2.cpp b/src/gui/rhi/qrhigles2.cpp
index 9a311101e1..9196a88199 100644
--- a/src/gui/rhi/qrhigles2.cpp
+++ b/src/gui/rhi/qrhigles2.cpp
@@ -2746,8 +2746,8 @@ void QRhiGles2::bindShaderResources(QRhiGraphicsPipeline *maybeGraphicsPs, QRhiC
             QGles2Buffer *bufD = QRHI_RES(QGles2Buffer, b->u.ubuf.buf);
             const QByteArray bufView = QByteArray::fromRawData(bufD->ubuf.constData() + viewOffset,
                                                                b->u.ubuf.maybeSize ? b->u.ubuf.maybeSize : bufD->m_size);
-            QVector<QGles2UniformDescription> &uniforms(maybeGraphicsPs ? QRHI_RES(QGles2GraphicsPipeline, maybeGraphicsPs)->uniforms
-                                                                        : QRHI_RES(QGles2ComputePipeline, maybeComputePs)->uniforms);
+            QGles2UniformDescriptionVector &uniforms(maybeGraphicsPs ? QRHI_RES(QGles2GraphicsPipeline, maybeGraphicsPs)->uniforms
+                                                     : QRHI_RES(QGles2ComputePipeline, maybeComputePs)->uniforms);
             for (QGles2UniformDescription &uniform : uniforms) {
                 if (uniform.binding == b->binding) {
                     // in a uniform buffer everything is at least 4 byte aligned
@@ -2877,8 +2877,8 @@ void QRhiGles2::bindShaderResources(QRhiGraphicsPipeline *maybeGraphicsPs, QRhiC
             break;
         case QRhiShaderResourceBinding::SampledTexture:
         {
-            QVector<QGles2SamplerDescription> &samplers(maybeGraphicsPs ? QRHI_RES(QGles2GraphicsPipeline, maybeGraphicsPs)->samplers
-                                                                        : QRHI_RES(QGles2ComputePipeline, maybeComputePs)->samplers);
+            QGles2SamplerDescriptionVector &samplers(maybeGraphicsPs ? QRHI_RES(QGles2GraphicsPipeline, maybeGraphicsPs)->samplers
+                                                     : QRHI_RES(QGles2ComputePipeline, maybeComputePs)->samplers);
             for (int elem = 0; elem < b->u.stex.count; ++elem) {
                 QGles2Texture *texD = QRHI_RES(QGles2Texture, b->u.stex.texSamplers[elem].tex);
                 QGles2Sampler *samplerD = QRHI_RES(QGles2Sampler, b->u.stex.texSamplers[elem].sampler);
@@ -3404,7 +3404,7 @@ void QRhiGles2::registerUniformIfActive(const QShaderDescription::BlockVariable
                                         int binding,
                                         int baseOffset,
                                         GLuint program,
-                                        QVector<QGles2UniformDescription> *dst)
+                                        QGles2UniformDescriptionVector *dst)
 {
     if (var.type == QShaderDescription::Struct) {
         qWarning("Nested structs are not supported at the moment. '%s' ignored.",
@@ -3431,7 +3431,7 @@ void QRhiGles2::registerUniformIfActive(const QShaderDescription::BlockVariable
 
 void QRhiGles2::gatherUniforms(GLuint program,
                                const QShaderDescription::UniformBlock &ub,
-                               QVector<QGles2UniformDescription> *dst)
+                               QGles2UniformDescriptionVector *dst)
 {
     QByteArray prefix = ub.structName + '.';
     for (const QShaderDescription::BlockVariable &blockMember : ub.members) {
@@ -3464,8 +3464,9 @@ void QRhiGles2::gatherUniforms(GLuint program,
     }
 }
 
-void QRhiGles2::gatherSamplers(GLuint program, const QShaderDescription::InOutVariable &v,
-                               QVector<QGles2SamplerDescription> *dst)
+void QRhiGles2::gatherSamplers(GLuint program,
+                               const QShaderDescription::InOutVariable &v,
+                               QGles2SamplerDescriptionVector *dst)
 {
     QGles2SamplerDescription sampler;
     sampler.glslLocation = f->glGetUniformLocation(program, v.name.constData());
diff --git a/src/gui/rhi/qrhigles2_p_p.h b/src/gui/rhi/qrhigles2_p_p.h
index 26a0925dee..32e7d1185d 100644
--- a/src/gui/rhi/qrhigles2_p_p.h
+++ b/src/gui/rhi/qrhigles2_p_p.h
@@ -266,6 +266,9 @@ struct QGles2SamplerDescription
 
 Q_DECLARE_TYPEINFO(QGles2SamplerDescription, Q_MOVABLE_TYPE);
 
+using QGles2UniformDescriptionVector = QVarLengthArray<QGles2UniformDescription, 8>;
+using QGles2SamplerDescriptionVector = QVarLengthArray<QGles2SamplerDescription, 4>;
+
 struct QGles2GraphicsPipeline : public QRhiGraphicsPipeline
 {
     QGles2GraphicsPipeline(QRhiImplementation *rhi);
@@ -275,8 +278,8 @@ struct QGles2GraphicsPipeline : public QRhiGraphicsPipeline
 
     GLuint program = 0;
     GLenum drawMode = GL_TRIANGLES;
-    QList<QGles2UniformDescription> uniforms;
-    QList<QGles2SamplerDescription> samplers;
+    QGles2UniformDescriptionVector uniforms;
+    QGles2SamplerDescriptionVector samplers;
     uint generation = 0;
     friend class QRhiGles2;
 };
@@ -289,8 +292,8 @@ struct QGles2ComputePipeline : public QRhiComputePipeline
     bool create() override;
 
     GLuint program = 0;
-    QList<QGles2UniformDescription> uniforms;
-    QList<QGles2SamplerDescription> samplers;
+    QGles2UniformDescriptionVector uniforms;
+    QGles2SamplerDescriptionVector samplers;
     uint generation = 0;
     friend class QRhiGles2;
 };
@@ -574,17 +577,17 @@ struct QGles2CommandBuffer : public QRhiCommandBuffer
         }
     } computePassState;
 
-    QList<QByteArray> dataRetainPool;
-    QList<QImage> imageRetainPool;
+    QVarLengthArray<QByteArray, 4> dataRetainPool;
+    QVarLengthArray<QImage, 4> imageRetainPool;
 
     // relies heavily on implicit sharing (no copies of the actual data will be made)
     const void *retainData(const QByteArray &data) {
         dataRetainPool.append(data);
-        return dataRetainPool.constLast().constData();
+        return dataRetainPool.last().constData();
     }
     const void *retainImage(const QImage &image) {
         imageRetainPool.append(image);
-        return imageRetainPool.constLast().constBits();
+        return imageRetainPool.last().constBits();
     }
     void resetCommands() {
         commands.clear();
@@ -810,11 +813,11 @@ public:
     bool linkProgram(GLuint program);
     void registerUniformIfActive(const QShaderDescription::BlockVariable &var,
                                  const QByteArray &namePrefix, int binding, int baseOffset,
-                                 GLuint program, QList<QGles2UniformDescription> *dst);
+                                 GLuint program, QGles2UniformDescriptionVector *dst);
     void gatherUniforms(GLuint program, const QShaderDescription::UniformBlock &ub,
-                        QList<QGles2UniformDescription> *dst);
+                        QGles2UniformDescriptionVector *dst);
     void gatherSamplers(GLuint program, const QShaderDescription::InOutVariable &v,
-                        QList<QGles2SamplerDescription> *dst);
+                        QGles2SamplerDescriptionVector *dst);
     bool isProgramBinaryDiskCacheEnabled() const;
 
     enum DiskCacheResult {
diff --git a/src/gui/rhi/qrhimetal.mm b/src/gui/rhi/qrhimetal.mm
index 357e9e792d..6998c55bf9 100644
--- a/src/gui/rhi/qrhimetal.mm
+++ b/src/gui/rhi/qrhimetal.mm
@@ -203,7 +203,7 @@ struct QRhiMetalData
         QSize pixelSize;
         QRhiTexture::Format format;
     };
-    QVector<TextureReadback> activeTextureReadbacks;
+    QVarLengthArray<TextureReadback, 2> activeTextureReadbacks;
 
     API_AVAILABLE(macos(10.13), ios(11.0)) MTLCaptureManager *captureMgr;
     API_AVAILABLE(macos(10.13), ios(11.0)) id<MTLCaptureScope> captureScope = nil;
@@ -2123,7 +2123,7 @@ void QRhiMetal::finishActiveReadbacks(bool forced)
             if (readback.result->completed)
                 completedCallbacks.append(readback.result->completed);
 
-            d->activeTextureReadbacks.removeAt(i);
+            d->activeTextureReadbacks.removeLast();
         }
     }
 
diff --git a/src/gui/rhi/qrhivulkan.cpp b/src/gui/rhi/qrhivulkan.cpp
index 06fd6dc719..919f4f039f 100644
--- a/src/gui/rhi/qrhivulkan.cpp
+++ b/src/gui/rhi/qrhivulkan.cpp
@@ -3525,7 +3525,7 @@ void QRhiVulkan::finishActiveReadbacks(bool forced)
             if (readback.result->completed)
                 completedCallbacks.append(readback.result->completed);
 
-            activeTextureReadbacks.removeAt(i);
+            activeTextureReadbacks.removeLast();
         }
     }
 
@@ -3549,7 +3549,7 @@ void QRhiVulkan::finishActiveReadbacks(bool forced)
             if (readback.result->completed)
                 completedCallbacks.append(readback.result->completed);
 
-            activeBufferReadbacks.removeAt(i);
+            activeBufferReadbacks.removeLast();
         }
     }
 
@@ -6719,9 +6719,9 @@ bool QVkSwapChain::ensureSurface()
 
     quint32 presModeCount = 0;
     rhiD->vkGetPhysicalDeviceSurfacePresentModesKHR(rhiD->physDev, surface, &presModeCount, nullptr);
-    QVector<VkPresentModeKHR> presModes(presModeCount);
-    rhiD->vkGetPhysicalDeviceSurfacePresentModesKHR(rhiD->physDev, surface, &presModeCount, presModes.data());
-    supportedPresentationModes = presModes;
+    supportedPresentationModes.resize(presModeCount);
+    rhiD->vkGetPhysicalDeviceSurfacePresentModesKHR(rhiD->physDev, surface, &presModeCount,
+                                                    supportedPresentationModes.data());
 
     return true;
 }
diff --git a/src/gui/rhi/qrhivulkan_p_p.h b/src/gui/rhi/qrhivulkan_p_p.h
index 3d02806033..cb21945301 100644
--- a/src/gui/rhi/qrhivulkan_p_p.h
+++ b/src/gui/rhi/qrhivulkan_p_p.h
@@ -601,7 +601,7 @@ struct QVkSwapChain : public QRhiSwapChain
     VkColorSpaceKHR colorSpace = VK_COLOR_SPACE_SRGB_NONLINEAR_KHR;
     QVkRenderBuffer *ds = nullptr;
     VkSampleCountFlagBits samples = VK_SAMPLE_COUNT_1_BIT;
-    QList<VkPresentModeKHR> supportedPresentationModes;
+    QVarLengthArray<VkPresentModeKHR, 8> supportedPresentationModes;
     VkDeviceMemory msaaImageMem = VK_NULL_HANDLE;
     QVkReferenceRenderTarget rtWrapper;
     QVkCommandBuffer cbWrapper;
@@ -865,7 +865,7 @@ public:
         int refCount = 0;
         int allocedDescSets = 0;
     };
-    QList<DescriptorPoolData> descriptorPools;
+    QVarLengthArray<DescriptorPoolData, 8> descriptorPools;
 
     VkQueryPool timestampQueryPool = VK_NULL_HANDLE;
     QBitArray timestampQueryPoolMap;
@@ -894,7 +894,7 @@ public:
         QSize pixelSize;
         QRhiTexture::Format format;
     };
-    QList<TextureReadback> activeTextureReadbacks;
+    QVarLengthArray<TextureReadback, 2> activeTextureReadbacks;
     struct BufferReadback {
         int activeFrameSlot = -1;
         QRhiBufferReadbackResult *result;
@@ -902,7 +902,7 @@ public:
         VkBuffer stagingBuf;
         QVkAlloc stagingAlloc;
     };
-    QList<BufferReadback> activeBufferReadbacks;
+    QVarLengthArray<BufferReadback, 2> activeBufferReadbacks;
 
     struct DeferredReleaseEntry {
         enum Type {